Android How to Program Paul J Deitel Test Bank

Type:

Test Bank

Resource:

Android How to Program

Edition:

1st Edition

Author(s):

Paul J. Deitel Harvey Deitel

Chapter 1—Introduction to Android: Test-Item File

1

Chapter 1—Introduction to Android: Test-Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

1.2 Android Overview 1.1 The Android operating system was developed by Google in July 2005.

ANS: Android, Inc.

, which was acquired by

1.2 (Self Review) In November 2007, the —a 34-company consortium initially and many more now—was formed to develop Android, driving innovation in mobile technology and improving the user experience while reducing costs.

ANS: Open Handset Alliance.

Openness and Open Source 1.3 (Self Review) (True/False) One benefit of developing Android apps is that the operating system is proprietary to Google.

ANS: False. The operating system is open source and free.

Java 1.4 (Exercise) Android apps are developed with —the world’s most widely used programming language, a logical choice because it’s powerful, free and open source.

ANS: Java.

1.5 (Self Review) (True/False) The openness of the Android platform discourages innovation.

ANS: False. The openness of the platform spurs rapid innovation.

1.6 (True/False) Java is object oriented and has access to powerful class libraries that help you develop apps quickly.

ANS: True.

1.7 (Exercise) GUI programming in Java is -driven, you’ll write apps that respond to various user interactions such as screen touches and keystrokes.

ANS: event.

2

Chapter 1

1.8 (Self Review) Using Eclipse with the Plugin, you can create, run, test and debug Android apps quickly and conveniently, and you can visually design your user interfaces.

ANS: Android Development Tools (ADT).

Multitouch Screen 1.9 with

(Self Review) Multitouch screens allow you to control your Android device involving one touch or multiple simultaneous touches.

ANS: gestures.

1.10 a

(Exercise) Touching the screen and holding your finger in position is called .

ANS: long press.

1.11 (Exercise) Touching and quickly flicking your finger across the screen in the direction you’d like to move is called a .

ANS: fling.

1.12 (True/False) Using two fingers, you can zoom in (moving your fingers apart) and out (pinching your fingers together) on photos, videos and web pages.

ANS: True.

1.3 Android 2.2 (Froyo) 1.13 If you’re unable to find your Android device, the feature restores it to the factory settings (removing all personal data), thus protecting the privacy of your information—any data that you haven’t backed up will be lost.

ANS: Remote Wipe.

New Developer Features in Android 2.2 1.14 The Android (C2DM) service allows app developers to send data from their servers to their apps installed on Android devices, even when the apps are not currently running. The server notifies the apps to contact the server directly to receive updated app or user data.

ANS: Cloud to Device Messaging.

1.15 (Self Review) You can create , which enable you to rapidly develop apps by combining the complementary web services of several organizations, possibly with information feeds of various types (such as RSS, Atom, XML, JSON and others).

ANS: mashups.

1.16 (Self Review) The Andriod contains APIs for audio focus, auto-scanning files to the media database (e.g., audio and video files), detecting sound loading completion, auto-pause and auto-resume of audio playback, and more.

ANS: Media framework.

Chapter 1—Introduction to Android: Test-Item File

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1.4 Android 2.3 (Gingerbread) 1.17 is a short-range wireless connectivity standard that enables communication between two devices, or a device and a tag, within a few centimeters.

ANS: Near-field communication 1.18

(True/False) Android apps can access only front-facing cameras.

ANS: False. Android apps can access both rear-facing and front-facing cameras.

1.5 Android 3.0 (Honeycomb) 1.19 app.

(Exercise) Use the

framework to add drag-and-drop capabilities in an

ANS: DragEvent.

1.20 (True/False) The Renderscript 3D graphics- engine creates high-performance 3D graphics for apps, widgets, etc. and offloading calculations to the Graphics Processing Unit (GPU).

ANS: True.

1.6 Android 4.0 (Ice Cream Sandwich) 1.7 Downloading Apps from the Android Market 1.21 (Exercise) As a marketing strategy, many app developers offer basic versions of their apps for free so users can determine whether they like them, then purchase more feature-rich versions.This is called the “ ” strategy.

ANS: lite.

1.8 Packages 1.22 (Self Review) Android uses a collection of related, predefined classes.

ANS: packages.

1.23

(Self Review) The package ANS: android.provider.

, which are named groups of

gives access to Android content providers.

1.9 Android Software Development Kit (SDK) Eclipse Integrated Development Environment (IDE) 1.24 (Exercise) (True/False) Microsoft Visual Studio is the recommended integrated development environment for Android development, though developers may also use a text editor and command-line tools to create Android apps.

4

Chapter 1 ANS: False. Eclipse is the recommended integrated development environment for An-

droid development, though developers may also use a text editor and command-line tools to create Android apps.

1.25 (True/False) Eclipse supports many programming languages, including Java, C++, C, Python, Perl, Ruby on Rails and more.

ANS: True.

1.26

(Exercise) (True/False) The vast majority of Android development is done in C++.

ANS: False. The vast majority of Android development is done in Java.

Android Development Tools (ADT) Plugin for Eclipse 1.27 (Self Review) (True/False) The Android Development Tools (ADT) Plugin for Eclipse—an extension to the Eclipse IDE—allows you to create, run and debug Android apps, export them for distribution (e.g., upload them to Android Market), and more.

ANS: True.

The Android Emulator 1.28 (Self Review) The , included in the Android SDK, allows you to run Android apps in a simulated environment within Windows, Mac OS X or Linux.

ANS: Android emulator.

1.29 (Exercise) Before running an app in the emulator, you'll need to create an , which defines the characteristics of the device on which you want to test, including the hardware, system image, screen size, data storage and more.

ANS: Android Virtual Device.

1.30 (Exercise) (True/False) You can reproduce on the emulator most of the Android gestures and controls using your computer’s keyboard and mouse.

ANS: True.

1.31

1.10

To test GPS apps in the emulator, you’ll need to create files that ANS: simulate GPS readings.

.

Object Technology: A Quick Refresher

1.32 (Exercise) (True/False) Objects, or more precisely the classes objects come from, are essentially reusable software components.

ANS: True.

1.33 (Self Review) Almost any noun can be reasonably represented as a software object in terms of (e.g., name, color and size) and behaviors (e.g., calculating, moving and communicating).

ANS: attributes.

1.34 (True/False) Software developers are discovering that using a modular, structured programming approach can make software development groups much more productive than was possible with earlier popular techniques like object-oriented programming.

ANS: False. Software developers are discovering that using a modular, object-oriented programming design and implementation approach can make software development groups much more productive than was possible with earlier popular

Chapter 1—Introduction to Android: Test-Item File

5

techniques like structured programming—object-oriented programs are often eas-ier to understand, correct and modify.

Methods and Classes 1.35 (Exercise) Performing a task in a program requires a program statements that actually perform its tasks.

ANS: method.

1.36 (Self Review) A program unit called a its tasks.

ANS: class.

which houses the

houses the methods that perform

Instantiation 1.37 (Exercise) You must build an object of a class before a program can perform the tasks that the class’s methods define. The process of doing this is called .

ANS: instantiation.

1.38

An object is referred to as an ANS: instance.

of its class.

Reuse 1.39 (Self Review) (True/False) You can reuse a class many times to build many objects.

Reuse of existing classes when building new classes and programs saves time and effort.

ANS: True.

1.40 (Exercise) helps you build more reliable and effective systems, because existing classes and components often have gone through extensive testing, debugging and performance tuning.

ANS: Reuse.

Messages and Methods Calls 1.41 (Self Review) You send messages to an object. Each message is a tells a method of the object to perform its task.

ANS: method call.

that

Attributes and Instance Variables 1.42 A car, besides having capabilities to accomplish tasks, also has , such as its color, its number of doors, the amount of gas in its tank, its current speed and its record of total miles driven (i.e., its odometer reading).

ANS: attributes.

1.43

(Self Review) (True/False) Attributes are specified by the class’s methods.

ANS: False. Attributes are specified by the class’s instance variables.

Encapsulation 1.44 (Exercise) Classes (i.e., wrap) attributes and methods into objects—an object’s attributes and methods are intimately related.

ANS: encapsulate.

6

Chapter 1

1.45 (Self Review) (True/False) Objects may communicate with one another, but they’re normally not allowed to know how other objects are implemented—implementation details are hidden within the objects themselves.

ANS: True.

Inheritance 1.46 (Exercise) A new class of objects can be created quickly and conveniently by —the new class absorbs the characteristics of an existing one, possibly customizing them and adding unique characteristics of its own.

ANS: inheritance.

Object-Oriented Analysis and Design (OOAD) 1.47 do.

A software development project’s ANS:

define what the system is supposed to

requirements.

1.11 Test-Driving the Doodlz App in an Android Virtual Device (AVD) 1.48 (Exercise) Unlike actual buttons on a device, vice’s touch screen.

ANS: soft.

buttons appear on the de-

1.49 (Exercise) Colors are defined using the RGBA color scheme in which the red, green, blue and components are specified by integers in the range 0–255.

ANS: alpha.

Running the Doodlz App on an Android Device 1.50 (True/False) When you build apps for distribution via the Android Market, you should test the apps only on AVDs. ANS: False. When you build apps for distribution via the Android Market, you should test the apps on as many actual devices as you can.

1.51

(True/False) Some Android features can be tested only on AVDs. ANS: False. Some features can be tested only on real devices.

Chapter 2--Android Market and App Business Issues: Test Item File

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Chapter 2--Android Market and App Business Issues: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

2.3 Android Best Practices 2.3.1 Compatibility 2.1 The elements listed in your app's manifest file describe the app’s feature needs, allowing Android Market to filter the app so that only users with compatible devices can view and download it.

ANS: <uses-feature>.

2.3.2 Supporting Multiple Screens 2.2 (Exercise) (True/False) You must design your app for every possible screen size and density.

ANS: False. You do not need (nor would you want to try) to design your app for every possible screen size and density.

2.3 (Self Review) (True/False) Android provides four generalized screen sizes (small, normal, large and extra large) and densities (low, medium, high and extra high), making it easier for you to design apps that work on multiple screens.

ANS: True.

2.3.3 Android User Interface Guidelines Icon Design Guidelines 2.4 In the , you’ll find templates for creating your own Android app icons in Adobe Photoshop and Adobe Illustrator.

ANS: Android Icon Templates Pack.

2

Chapter 2

Widget Design Guidelines 2.5 (Exercise) are displays of timely information on the user’s Home screen, such as the current weather, stock prices and news.

ANS: Widgets.

Activity and Task Design Guidelines 2.6 (Exercise) are reusable components used to build an app’s user interface. They perform actions such as searching, viewing information and dialing a phone number. A separate one is often associated with each different screen of an app.

ANS: Activities.

2.7 (Self Review) The is a reverse chronological history of all of the activities, allowing the user to navigate to the previous activity using the Back button.

ANS: activity stack.

2.8 An Android is a series of activities that enables the user to complete an objective within an app or across multiple apps.

ANS: task.

Menu Design Guidelines 2.9 (Exercise) The menu—accessed through the device’s ton—provides actions and operations for the app’s current screen.

ANS: Options.

Menu

but-

2.10 (Self Review) Selecting the Context menu from within a message in the Messaging app (by touching and holding—also called —within the message on a touchscreen) brings up a menu of options specific to that message, including Select all, Select text, Cut all, Copy all, Paste and Input method.

ANS: long pressing.

2.11 (Exercise) If your app takes a while to load, use a —an image that will be displayed when the icon is tapped on the screen so that the user sees an immediate response while waiting for the app to load.

ANS: splash screen.

2.12 (Self Review) (True/False) A splash screen usually resembles the app’s user interface—often just an image of the background elements of the GUI. ANS: True.

2.13 (Exercise) (True/False) Use a BroadcastReceiver to easily share data from your app with other apps on the device.

ANS: False. Use a ContentProvider to easily share data from your app with other apps on the device.

Designing for Accessibility 2.14 Android includes built-in tools to help you design apps that are accessible to people with disabilities such as low vision or blindness. The speech synthesis capability (available in English, Spanish, French, German and Italian) allows apps to “speak” text strings.

ANS: Text-to-Speech (TTS).

Chapter 2--Android Market and App Business Issues: Test Item File

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2.4 Registering at Android Market 2.15

(True/False) Android Market has a careful approval process for uploading apps.

ANS: False. Unlike with other popular mobile platforms, Android Market has no approval process for uploading apps.

2.5 Setting Up a Google Checkout Merchant Account 2.16 (Self Review) To sell your apps on Android Market, you’ll need a chant account.

ANS: Google Checkout

mer-

2.6 AndroidManifest.xml File 2.17 (Exercise) The file, referred to as the manifest, provides information needed to run your app in Android and to filter it properly in Android Market.

ANS: AndroidManifest.xml.

2.18 The ADT Plugin for Eclipse includes an , which enables you to easily edit the manifest file rather than updating the code directly in the XML file.

ANS: Android Manifest Editor.

2.7 Preparing Your Apps for Publication Testing Your App 2.19 (Self Review) (True/False) When an app works perfectly using the emulator on your computer, it will run on your Android device.

ANS: False. Although the app might work perfectly using the emulator on your computer, problems could arise when running it on a particular Android device.

2.20 (Exercise) (True/False) The functionality of these sensors—accelerometer, barometer, compass, light sensor and proximity sensor—is not available on the emulator.

ANS: True.

End User License Agreement 2.21 (Exercise) An is an agreement through which you license your software to the user. It typically stipulates terms of use, limitations on redistribution and reverse engineering, product liability, compliance with applicable laws and more.

ANS: End User License Agreement (EULA).

Shrinking, Optimizing and Obfuscating Your App Code 2.22 The Android Market access to your paid apps.

ANS: licensing service.

allows you to create licensing policies to control

4

Chapter 2

2.23 (Self Review) (True/False) You might use a licensing policy to limit how often the app checks in with the server, how many simultaneous device installs are allowed, and what happens when an unlicensed app is identified.

ANS: True.

2.24 (Exercise) (True/False) You should “obfuscate” any apps you upload to Android Market to encourage reverse engineering of your code.

ANS: False. You should “obfuscate” any apps you upload to Android Market to prevent reverse engineering of your code and further protect your apps. The ProGuard tool—which runs when you build your app in release mode—shrinks the size of your .apk file and optimizes and obfuscates the code.

Getting a Private Key for Digitally Signing Your App 2.25 (Self Review) Before uploading your app to a device, to Android Market or to other app marketplaces, you must digitally sign the .apk file (Android app package file) using a that identifies you as the author of the app.

ANS: digital certificate.

2.26 (True/False) A digital certificate includes your name or company name, contact information, etc. It can be self-signed using a private key (i.e., a secure password used to encrypt the certificate).

ANS: True.

2.27 (True/False) During development, Eclipse automatically digitally signs your app so that you can run it on test devices. That digital certificate is valid for use with the Android Market.

ANS: False. That digital certificate is not valid for use with the Android Market.

2.28 (Exercise) The , which is installed with the ADT Plugin for Eclipse, helps you debug your apps running on actual devices.

ANS: Dalvik Debug Monitor Service (DDMS).

2.29

(True/False) The DDMS also enables you to capture screenshots on your device.

ANS: True.

2.8 Uploading Your Apps to Android Market Listing Details 2.30 (Self Review) (True/False) The title of your app as it will appear in Android Market must be unique among all Android apps.

ANS: False. The title of your app as it will appear in Android Market does not need to be unique among all Android apps.

2.9 Other Android App Marketplaces 2.31 (True/False) In addition to Android Market, you may choose to make your apps available through other Android app marketplaces, or even through your own website using services such as AndroidLicenser.

ANS: True.

Chapter 2--Android Market and App Business Issues: Test Item File

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2.10 Pricing Your App: Free or Fee Paid Apps 2.32 (Self Review) (True/False) According to a study by app store analytics firm Distimo (www.distimo.com/), the average price of paid Android apps is around $36.20.

ANS: False. According to the study, the average price of paid Android apps is around $3.62 (the median is $2.72).

2.33 (Exercise) (True/False) According to AdMob (www.admob.com/), Android users who purchase apps download an average of five apps per month.

ANS: True.

2.34 (True/False) All financial transactions for paid apps in Android Market are handled

by Google Checkout.

ANS: False. Financial transactions for paid apps in Android Market are handled by Google Checkout (checkout.google.com), though customers of some mobile carriers (such as AT&T, Sprint and T-Mobile) can opt to use carrier billing to charge paid apps to their wireless bill.

Free Apps 2.35

(Exercise) (True/False) There are now more free apps for Android than iPhone.

ANS: True.

2.36 (Exercise) (True/False) Approximately 90% of apps on Android Market are free, and they comprise the vast majority of downloads.

ANS: False. Approximately 57% of apps on Android Market are free, and they comprise the vast majority of downloads.

2.37 (Exercise) According to a recent study by AdMob, reason why users purchase a paid app.

ANS: upgrading from the “lite” version.

2.11

is the number one

Monetizing Apps with In-App Advertising

2.38 (True/False) Unless your app is widely downloaded and used, it will generate minimal advertising revenue.

ANS: True.

2.12 Monetizing Apps: Using In-App Billing to Sell Virtual Goods in Your Apps 2.39 The Android Market In-app Billing service enables you to sell ital content) through apps on devices running Android 2.3 or higher.

ANS: virtual goods.

(e.g., dig-

2.40 (Self Review) (True/False) According to Google, apps that use in-app billing earn profoundly more revenue than paid apps alone.

ANS: True.

6

Chapter 2

In-app Purchase for Apps Sold Through Other App Marketplaces 2.41 (Self Review) (True/False) If you choose to sell your apps through other app marketplaces, several third-party mobile payment providers can enable you to build in-app purchase into your apps using APIs from mobile payment providers.

ANS: True.

2.13 Managing Your Apps in Android Market 2.42 (Self Review) The Android Market allows you to manage your account and your apps, check users’ star ratings for your apps (0 to 5 stars), track the overall number of installs of each app and the number of active installs (installs minus uninstalls).

ANS: Developer Console.

2.14 Marketing Your App 2.43 (Exercise) (True/False) According to comScore, YouTube and Facebook each account for 10% of all time spent online worldwide.

ANS: False. According to comScore, YouTube accounts for 10% of all time spent online worldwide and Facebook accounts for a remarkable 17%.

Chapter 3—Welcome App: Test Item File

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Chapter 3—Welcome App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

3.1 Introduction 3.1 (Self Review) (True/False) The Eclipse IDE and the ADT (Android Development Tools) Plugin are the most popular tools for creating and testing Android apps.

ANS: True.

3.2 (Exercise) The ADT’s techniques.

ANS: Visual Layout Editor.

allows you to build GUIs using drag-and-drop

3.5 Building the Welcome App’s GUI with the ADT’s Visual Layout Editor 3.3 (Exercise) For an Android app that you create with Eclipse, the GUI layout is stored in an XML file called , by default.

ANS: main.xml.

3.4 (True/False) Defining the GUI in XML prevents you from separating your app’s logic from its presentation.

ANS: False. Defining the GUI in XML allows you to easily separate your app’s logic from its presentation.

3.5 ject’s

(Self Review) Layout files are considered app resources and are stored in the profolder. GUI layouts are placed within that folder’s layout subfolder.

ANS: res.

The Default GUI 3.6 (Exercise) The default GUI for a new Android app consists of a with a black background.

ANS: LinearLayout.

(layout)

3.7 (Self Review) (True/False) A LinearLayout always arranges GUI components in a line horizontally.

2

Chapter 3 ANS: False. LinearLayout arranges GUI components in a line horizontally or verti-

cally.

3.8 (Exercise) The (layout) allocates space for a single component. You can add more than one component to this layout, but each will be displayed from the layout’s upper-left corner. The last component added will appear on top.

ANS: FrameLayout.

3.9 The layout one column.

arranges components horizontally in one row or vertically in

ANS: LinearLayout.

3.10 (Self Review) (True/False) The layout RelativeLayout arranges components relative to one another or relative to their parent container.

ANS: True.

3.11 (True/False) The layout TableLayout arranges components into a table of columns.

You can then use the TableRow layout (a subclass of LinearLayout) to organize the columns.

ANS: False. The layout TableLayout arranges components into a table of rows. You can then use the TableRow layout (a subclass of LinearLayout) to organize the columns.

Configuring the Visual Layout Editor’s Size and Resolution 3.12 be

(Self Review) When designing an Android GUI, you typically want it to so that it displays properly on various devices.

ANS: scalable.

Images and Screen Sizes/Resolutions 3.13 (True/False) Because Android devices have various screen sizes, resolutions and pixel densities (that is, dots per inch or DPI), Android allows you to provide separate images (and other resources) that the operating system chooses based on the actual device’s pixel density.

ANS: True.

3.14 (Exercise) Your project’s res folder contains three subfolders for images—drawable-hdpi (high density), drawable-mdpi (medium density) and drawable-ldpi (low density). These folders store images with different densities.

ANS: pixel.

3.15 (Self Review) The Android pixel density not be scaled regardless of screen density.

ANS: nodpi.

indicates that a resource should

3.16 (Exercise) (True/False) For images to render nicely, a high-pixel-density device needs lower-resolution images than a low-pixel-density device.

ANS: False. For images to render nicely, a high-pixel-density device needs higher-resolution images than a low-pixel-density device.

3.17

(True/False) Low-resolution images do not scale well.

ANS: True.

Chapter 3—Welcome App: Test Item File

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Step 3: Changing the Background Property of the RelativeLayout 3.18 (Exercise) (True/False) Every color can be created from a combination of red, green and blue components called RGB values—each is an integer in the range 0–256.

ANS: False. Every color can be created from a combination of red, green and blue components called RGB values—each is an integer in the range 0–255.

3.19 (Self Review) To change the background color to white, locate the Background property in the Properties window and set its value to .

ANS: #FFFFFF. 3.20 (Self Review) (True/False) Android also supports alpha (transparency) values in the range 0–100, where 0 represents completely transparent and 100 represents completely opaque.

ANS: False. Android also supports alpha (transparency) values in the range 0–255, where 0 represents completely transparent and 255 represents completely opaque.

3.21 mat

(Exercise) If you wish to use alpha values, you can specify the color in the for, where the first two hexadecimal digits represent the alpha value.

ANS: #AARRGGBB.

3.22 For cases in which both digits of each component of the color are the same, you can use the formats #RGB or #ARGB. For example, #FFF will be treated as .

ANS: #FFFFFF.

Step 5: Configuring the TextView’s Text Property Using a String Resource 3.23 (Exercise) (True/False) It’s considered a good practice to “externalize” strings, string arrays, images, colors, font sizes, dimensions and other app resources so that you, or someone else on your team, can manage them separately from your application’s code.

ANS: True.

3.24 (True/False) If you externalize color values, all components that use the same color can be updated to a new color simply by changing the color value in a central resource file.

ANS: True.

3.25 If you wish to localize your app in several different languages, storing the strings separately from the app’s code allows you to change them easily. In your project’s res folder, the subfolder values contains a file that’s used to store strings. To provide localized strings for other languages, you can create separate values folders for each language.

ANS: strings.xml.

3.26 (Self Review) You can easily your app by creating additional XML resource files for string resources in other languages.

ANS: localize.

Step 6: Configuring the TextView’s Text size and Padding top Properties—Scaled Pixels and Density-Independent Pixels 3.27 (Exercise) The documentation for supporting multiple screen sizes recommends that you use density-independent pixels for the dimensions of GUI components and other screen elements and for font sizes.

ANS: scale-independent pixels

4

Chapter 3

3.28 (True/False) Defining your GUIs with density-dependent pixels enables the Android platform to automatically scale the GUI, based on the pixel density of the actual device’s screen.

ANS: False. Defining your GUIs with density-independent pixels enables the Android platform to automatically scale the GUI, based on the pixel density of the actual device’s screen.

3.29 are

(Self Review) The two measurement units for density independent pixels and .

ANS: dp and dip.

3.30 (Exercise) One density-independent pixel is equivalent to one pixel on a screen with 160 dpi (dots per inch). On a screen with 240 dpi, each density-independent pixel will be scaled by a factor of .

ANS: 240/160 (i.e., 1.5).

3.31 (Exercise) On a screen with 120 dpi, each density-independent pixel is scaled by a factor of . So, the same component that’s 100 density-independent pixels wide will be 75 actual pixels wide.

ANS: 120/160 (i.e., .75).

3.32 (True/False) Scale-independent pixels are scaled like density-independent pixels, and they’re also scaled by the user’s preferred font size specified on the device.

ANS: True.

3.6 Examining the main.xml File welcomeRelativeLayout

3.33 (Exercise) Specifying the value match_parent for both the android:layout_width and android:layout_height attributes, causes the layout to occupy the entire width and height of layout’s element—that is, the one in which this layout is nested.

ANS: parent. welcomeTextView

3.34 (Self Review) Setting the android:layout_width and android:layout_height attributes to indicates that the view should be just large enough to fit its content, including its padding values that specify the spacing around the content.

ANS: wrap_content.

3.35 (Self Review) (True/False) Setting the android-:lay-out_centerHorizontal attribute to "yes" centers the component horizontally in the layout.

ANS: False. Setting the android-:lay-out_centerHorizontal attribute to "true" centers the component horizontally in the layout.

3.36

(Exercise) Setting the

attribute to "center" centers the text in the

TextView.

ANS: android:gravity.

3.37 The android:gravity attribute specifies how the text should be positioned with respect to the width and height of the TextView if the text is larger than the TextView.

Chapter 3—Welcome App: Test Item File

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ANS: False. The android:gravity attribute specifies how the text should be positioned with respect to the width and height of the TextView if the text is smaller than the TextView.

3.7 Running the Welcome App 3.38 (Self Review) To run an app in an Android Virtual Device (AVD), right click the app’s root node in Eclipse in the window and select Run As > Android Application.

ANS: Package Explorer.

3.8 Wrap-Up 3.39 (Exercise) (True/False) You can use the Visual Layout Editor to create a working Android app without writing any code.

ANS: True.

3.40 and

(Exercise) Android development and XML coding.

ANS: Java.

is

a

combination

of

GUI

design,

Instructor Note

1

Chapter 4--Tip Calculator App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

4.1 Introduction Select a Custom Tip Percentage 4.1 255.

(Exercise) (True/False) By default, a Seekbar allows you to select values from 0 to ANS: False. By default, a Seekbar allows you to select values from 0 to 100.

4.3 Technologies Overview 4.2 (Self Review) An —often called a text box or text field in other GUI technologies—is a subclass of Text-View that can display text and accept text input from the user.

ANS: EditText.

4.3 A —often called a slider in other GUI technologies—represents an integer in the range 0–100 by default and allows the user to select a number in that range.

ANS: SeekBar.

4.4 Building the App’s GUI 4.4.1 TableLayout Introduction 4.4

(Self Review) Use a

to arrange GUI components into rows and columns.

ANS: TableLayout.

4.5

(Exercise) (True/False) A GUI component can span multiple columns in a Table-

Layout.

ANS: True.

4.6 (True/False) When you use TableRow objects, each row’s height is determined by the tallest component in that row, the width of a column is defined by the widest element in that

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Chapter 4

column—unless you allow the table’s columns to stretch to fill the width of the screen, in which case the columns could be wider.

ANS: True.

4.7 (Self Review) (True/False) Android requires that you use the GUI component’s class name in each component’s Id property in the XML layout and in each component’s variable name in the Java code.

ANS: True.

4.4.2 Creating the Project and Adding the TableLayout and Components 4.8 (Exercise) String literals should be placed in the strings.xml file in the app’s folder—especially if you intend to localize your app for use with multiple languages.

ANS: res/values.

4.9 (Self Review) When working with more complex layouts like TableLayouts, it’s difficult to see the nested structure of the layout and to place components in the correct nested locations using the Visual Layout Editor. The window makes these tasks easier because it shows the nested structure of the GUI. So, in a TableLayout, you can select the appropriate row and add a GUI component to it.

ANS: Outline.

Step 1: Creating the TipCalculator Project 4.10

(True/False) Eclipse allows several projects with a given name per workspace.

ANS: False. Eclipse allows only one project with a given name per workspace.

Step 3: Configuring the Visual Layout Editor to Use the Appropriate Android SDK 4.11 (Exercise) (True/False) If you’ve installed multiple Android SDKs, the ADT Plugin selects the oldest one as the default for design purposes in the Graphical Layout tab—regardless of the SDK you selected when you created the project.

ANS: False. If you’ve installed multiple Android SDKs, the ADT Plugin selects the most recent one as the default for design purposes in the Graphical Layout tab—regardless of the SDK you selected when you created the project.

4.4.3 Customizing the Components to Complete the Design Step 13: Change the Text color Property of All the TextViews 4.12 (True/False) In the Outline window, you can select multiple components at the same time by holding the Ctrl (or Control) key as you click each component that you wish to select.

When you do this, the Properties window shows you only the properties that the selected components have in common. If you change a property value with multiple components selected, that property’s value is changed for every selected component.

ANS: True.

Instructor Note

3

Step 19: Setting the customSeekBar’s Progress Property and Padding 4.13 (True/False) When you move the thumb to the far left or far right of the SeekBar (representing 0 and 100, respectively), the thumb becomes hard for the user to grab if there is not enough space between the SeekBar and the components to its left and right.

ANS: True.

Step 20: Preventing the User from Manipulating Text in the EditTexts That Show Calculation Results 4.14 (Exercise) You can control whether or not the user can give the focus to an EditText by setting its property.

ANS: Focusable.

4.15 (Self Review) (True/False) You can force an EditText to display a cursor so that the user can’t manipulate the text.

ANS: False. You can prevent an EditText from displaying a cursor so that the user can’t manipulate the text.

Step 22: Set the Layout Weights of Various Components 4.16 (Exercise) A component’s to other components.

specifies its relative importance with respect

ANS: Layout weight.

4.17

By default, all components have a Layout weight of ANS: 0.

.

4.18 (Self Review) (True/False) Each component’s Relative weight determines how it should be sized relative to other components.

ANS: False. Each component’s Layout weight determines how it should be sized relative to other components.

4.5 Adding Functionality to the App The package and import Statements 4.19 (Exercise) Class methods of an app.

ANS: Activity.

4.20 (Self Review) Class information.

ANS: Bundle.

of package android.app provides the basic lifecycle

of package android.os represents an app’s state

4.21 (True/False) An app can save its state when it’s sent to the background by the operating system—for example, when the user launches another app or a phone call is received.

ANS: True.

4.22 (Exercise) Interface content and markup of text in a GUI. ANS: Editable.

of package android.text allows you to change the

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Chapter 4

4.23 (Self Review) You implement interface of package android.text to respond to events when the user interacts with an EditText component.

ANS: TextWatcher.

4.24 Package contains the widgets (i.e., GUI components) and layouts that are used in Android GUIs, such as EditText, SeekBar and TextView.

ANS: android.widget.

4.25 (Exercise) You implement interface respond to the user moving the SeekBar’s thumb.

of package android.widget to

ANS: SeekBar.OnSeekBarChangeListener

Tip Calculator App Activity and the Activity Lifecycle 4.26 (Self Review) (True/False) As with all Java programs, Android apps have a main method.

ANS: False. Android apps don’t have a main method.

4.27 (Exercise) Android apps have four types of components—activities, services, content providers and .

ANS: broadcast receivers.

4.28

(True/False) Users interact with activities through views—that is, GUI components.

ANS: True.

4.29 app.

(Self Review) A separate

is typically associated with each screen of an

ANS: activity.

4.30 (Exercise) (True/False) Every Activity subclass must override the Construct method.

ANS: False. Every Activity subclass must override the onCreate method.

4.31 (Exercise) Throughout its life an activity can be in one of several states—active (or running), paused or . The activity transitions between these states in response to various events.

ANS: stopped.

4.32 (Self Review) (True/False) An active (or running) activity is visible on the screen and “has the focus”—that is, it’s in the background. This is the activity the user is interacting with.

ANS: False. An active (or running) activity is visible on the screen and “has the focus”—that is, it’s in the foreground. This is the activity the user is interacting with.

4.33

(Exercise) (True/False) A paused activity is visible on the screen and has the focus.

ANS: False. A paused activity is visible on the screen but doesn’t have the focus.

4.34 (True/False) A stopped activity can be killed when its memory is needed by the operating system (perhaps to run another app), but paused activities are killed first.

ANS: False. A paused activity can be killed when its memory is needed by the operating system (perhaps to run another app), but stopped activities are killed first.

4.35 (Self Review) (True/False) A stopped activity is visible on the screen and is likely to be killed by the system when its memory is needed.

ANS: False. A stopped activity is not visible on the screen and is likely to be killed by the system when its memory is needed.

Instructor Note

5

4.36 (Self Review) The method is called by the system when an Activity is starting—that is, when its GUI is about to be displayed so that the user can interact with the Activity.

ANS: onCreate.

4.37 (Exercise) The method is called by the system when the configuration of the device changes during the app’s execution—for example, when the user rotates the device or slides out a keyboard on a device with a hard keyboard.

ANS: onSaveInstanceState.

4.38 (True/False) When an app is simply placed into the background, perhaps so the user can answer a phone call or when the user starts another app, the app’s GUI components will automatically save their contents for when the app is brought back to the foreground (provided that the system does not kill the app).

ANS: True.

Overriding Method OnCreate of Class Activity 4.39 The method—which is auto-generated when you create the app’s project—is called by the system when an Activity is started.

ANS: onCreate.

4.40 (Self Review) (True/False) Method onCreate typically initializes the Activity’s instance variables and GUI components. This method should be as simple as possible so that the app loads quickly. In fact, if the app takes longer than five seconds to load, the operating system will display an ANR (Application Not Responding) dialog—giving the user the option to forcibly terminate the app.

ANS: True.

4.41 (Exercise) (True/False) Time-consuming initializations should be done in a onCreate method instead of the background process.

ANS: False. Time-consuming initializations should be done in a background process instead of the onCreate method.

(Self Review) As you build your app’s GUI and add resources (such as strings in the strings.xml file or GUI components in the main.xml file) to your app, the ADT Plugin tools generate a class named that contains nested static classes representing each type of resource in your project’s res folder.

ANS: R. 4.42

4.43

(Self Review) Class (nested in class R)—contains constants for any drawable items, such as images, that you put in the various drawable folders in your app’s res folder.

ANS: R.drawable.

4.44 (Exercise) Class (nested in class R)—contains constants for the GUI components in your XML layout files.

ANS: R.id.

4.45 Class (nested in class R)—contains constants that represent each layout file in your project (such as, main.xml).

ANS: R.layout

4.46

(Self Review) Class

String in the strings.xml file.

(nested in class R)—contains constants for each

6

Chapter 4 ANS: R.string

4.47 (Exercise) Method setContentView uses a received constant to load the corresponding XML document, which is then parsed and converted into the app’s GUI. This process is known as the GUI. ANS: inflating.

4.48 (Self Review) Once the layout is inflated, you can get references to the individual widgets using Activity’s method. This method takes an int constant for a specific view (that is, a GUI component) and returns a reference to it.

ANS: findViewById. 4.49 (True/False) The name of each GUI component’s constant in the R.id class is determined by the GUI component’s android:name attribute in the main.xml file.

ANS: False. The name of each GUI component’s constant in the R.id class is determined by the GUI component’s android:id attribute in the main.xml file.

Overriding Method onSaveInstanceState of Class Activity

4.6 Wrap-Up 4.50 to

(Self Review) You use a TableLayout to arrange the GUI components inand .

ANS: rows, columns.

4.51

(Exercise) (True/False) You use TableRows to create the rows in a TableLayout.

ANS: True.

4.52 the

The number of columns in a TableLayout is defined by the TableRow that contains components.

ANS: most.

4.53 (Exercise) (True/False) You override the onStart method to initialize the app when it’s launched.

ANS: False. You override the onCreate method to initialize the app when it’s launched.

4.54 (True/False) You override the onSaveAppState method to save app state when the device’s configuration changes.

ANS: False. You override the onSaveInstanceState method to save app state when the device’s configuration changes.

4.55 In the onCreate method, you use Activity method to get references to each of the GUI components that the app interacts with programmatically. findViewById.

Chapter 5—Favorite Twitter® Searches App: Test Item File

1

Chapter 5—Favorite Twitter® Searches App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

5.3 Technologies Overview 5.1 (Exercise) A is a ViewGroup that can contain other Views (like a layout) and that lets users scroll through content too large to display on the screen.

ANS: ScrollView.

SharedPreferences

5.2 the

When

an app is launched, which handles the GUI. ANS: UI thread.

Android

creates

a

main

thread

called

5.3 (Self Review) (True/False) Extensive input/output should be performed on the UI thread, otherwise that would affect your app’s responsiveness.

ANS: False. Extensive input/output should not be performed on the UI thread, since that would affect your app’s responsiveness.

Intents

5.4 (Self Review) are typically used to launch activities—they indicate an action to be performed and the data on which that action is to be performed.

ANS: Intents.

LayoutInflater

5.5 (Exercise) The nents specified in the XML.

inflates an XML layout file, thus creating the compo-

ANS: Layout-Inflater.

AndroidManifest.xml

5.6 (True/False) The AndroidManifest.xml file is created for you when you create an app using the ADT Plugin in Eclipse.

ANS: True.

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Chapter 5

5.4 Building the App’s GUI and Resource Files 5.4.1 Creating the Resource Files colors.xml

5.7 Each XML document that represents resources must contain a which you specify the resources.

ANS: resources.

element in

dimen.xml

5.8 (Self Review) (True/False) A benefit of defining dimensions as resources is that you can use density-independent pixel (dp or dip) and scale-independent pixel (sp) values, which Android automatically converts to the appropriate pixel values for a given device.

ANS: True.

5.4.2 Adding the TableLayout and Components Step 4: Configuring the TableLayout 5.9 (Exercise) A layout fills the entire screen if the Layout width and Layout height properties have the value .

ANS: match_parent.

5.5 Building the App The package and import Statements 5.10 (Self Review) We implement interface when the user touches a button on an AlertDialog.

ANS: OnClickListener.

to handle the events that occur

5.11 (Exercise) (True/False) An Algorithm specifies an action to be performed and the data to be acted upon—Android uses Algorithms to launch the appropriate activities.

ANS: False. An Intent specifies an action to be performed and the data to be acted upon—Android uses Intents to launch the appropriate activities.

5.12 Class of package android-.widget represents a simple push button that the user touches to get the app to perform a specific action.

ANS: Button.

5.13 (Exercise) (True/False) You implement interface View.OnClickListener of package android.view to specify the code that should execute when the user touches a Button.

ANS: True.

Chapter 5—Favorite Twitter® Searches App: Test Item File

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Overridden Method OnCreate of Class Activity 5.14 (Exercise) The method is called by the system when the app loads, if the app’s process was killed by the operating system while the app was in the background, and the app is then restored, each time the configuration changes, such as when the user rotates the device or opens/closes a physical keyboard.

ANS: onCreate.

5.15 (Self Review) Lengthy data access should never be done in the UI thread; otherwise, the app will display an dialog—typically after five seconds of inactivity.

ANS: Application Not Responding (ANR). refreshButtons Method of Class FavoriteTwitterSearches

5.16 SharedPreferences method pairs.

ANS: getAll.

returns a Map containing all the key/value

5.17 (Self Review) (True/False) You call toArray (with an empty String array as an argument) on the Set object to convert the Set into an array of Strings.

ANS: True.

5.18 (Exercise) (a static method of class Arrays from package java.util) sorts the array in its first argument.

ANS: Arrays.sort.

5.19

(True/False) To perform a case-insensitive sort, pass the predefined Comparator<String> object String.CASE_INSENSITIVE_ORDER as the second argument to Arrays.sort.

ANS: True. makeTagGUI Method of Class FavoriteTwitterSearches

5.20 Android provides a service that enables you to inflate a layout. To use this service, you obtain a reference to it by calling the Activity’s inherited method with the argument Context.LAYOUT_INFLATER_SERVICE. ANS: getSystemService.

Anonymous Inner Class That Implements Interface OnClickListener to Respond to the Events of each of the newTagButtons 5.21 ed

(Self Review) An Intent is a description of an action to be performed with associat.

ANS: data.

5.22 (Exercise) (True/False) The first argument passed to Intent’s constructor is the data to be operated on.

ANS: False. The first argument passed to Intent’s constructor is a constant describing the action we wish to perform.

5.23 (True/False) We use Intent.DATA_VIEW because we wish to display a representation of the data.

ANS: False. We use Intent.ACTION_VIEW because we wish to display a representation of the data.

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Chapter 5

5.24 (True/False) Many constants are defined in the Intent class describing actions such as searching, choosing, sending and playing.

ANS: True.

5.25 The second argument passed to the Intent’s constructor is a Uri (uniform resource identifier) to the on which we want to perform the action.

ANS: data.

5.26 (Exercise) (True/False) With an explicit Intent, we allow the system to launch the most appropriate Activity based on the type of data.

ANS: False. With an implicit Intent, we allow the system to launch the most appropriate Activity based on the type of data.

5.27 (Self Review) same app.

Intents specify an exact Activity class to run in the

ANS: Explicit.

5.6 AndroidManifest.xml 5.28 (Self Review) When you create the project for each Android app in Eclipse, the ADT Plugin creates and configures the file (also known as the app’s manifest), which describes information about the app.

ANS: AndroidManifest.xml.

5.29 (True/False) The element’s android:icon attribute specifies a drawable resource which is used as the app’s icon.

ANS: True.

5.30 (Exercise) (True/False) If you don’t provide your own icon, the app uses the icon that’s supplied by the ADT Plugin when you create the app’s project.

ANS: True.

5.31

(Self Review) The

attribute specifies the app’s name.

ANS: android:label.

5.32

(True/False) The sdk element specifies the app’s target SDK and its minimum SDK. ANS: False. The uses-sdk element specifies the app’s target SDK and its minimum SDK.

5.33 (Self Review) Within the activity element is the fies the types of intents the Activity can respond to.

ANS: intent-filter.

element, which speci-

5.34 (True/False) The category element specifies the kind of Android component that handles the event.

ANS: True.

5.35

(Exercise) (True/False) The category element value "android.application.category.LAUNCHER" indicates that this activity should be listed in the application launcher with other apps on the device.

ANS: False. The category element value "android.intent.category.LAUNCHER" indicates that this activity should be listed in the application launcher with other apps on the device.

Chapter 5—Favorite Twitter® Searches App: Test Item File

5

5.7 Wrap-Up 5.36 (Exercise) You use displaying messages to the user.

ANS: AlertDialog.Builder.

objects to configure and create AlertDialogs for

Chapter 6—Flag Quiz Game App: Test Item File

1

Chapter 6—Flag Quiz Game App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

6.3 Technologies Overview Using the App’s assets Folder 6.1

(Self Review) Files in the assets folders are accessed via an (package android.content.res), which can provide a list of all of the file names in a specified subfolder of assets and can be used to access each asset.

ANS: AssetManager.

Using a Menu to Provide App Options 6.2 (True/False) To specify the Menu options, you override Activity’s on-Create-Menu method and add the options to the Menu that the method receives as an argument.

ANS: False. To specify the Menu options, you override Activity’s on-Create-OptionsMenu method and add the options to the Menu that the method receives as an argument.

6.3 od

(Exercise) When the user selects an item from a Menu, Activity methis called to respond to the selection.

ANS: onOptionsItemSelected.

Using a Handler to Execute a Runnable in the Future 6.4 (Exercise) To delay an action, we use a to execute a Runnable after a specified delay.

ANS: Handler.

(package android-.os) object

6.5 (True/False) Handler method postDelayed receives as arguments a Runnable to execute and a delay in seconds.

ANS: False. Handler method postDelayed receives as arguments a Runnable to execute and a delay in milliseconds.

Animating the Flag When an Incorrect Choice Is Touched 6.6

(Self Review) (True/False) We use AnimationUtils static method loadAnimation to load an animation from an XML file that specifies the animation’s options.

2

Chapter 6 ANS: True.

6.7

(Exercise) We also specify the number of times an animation should repeat with Animation method and perform the animation by calling View method startAnimation (with the Animation as an argument) on the ImageView.

ANS: setRepeatCount.

Logging Exception Messages with Log.e 6.8 (Self Review) (True/False) When exceptions occur, you can log them for debugging purposes with Android’s built-in logging mechanism, which uses a circular buffer to store the messages for a short time.

ANS: True.

6.4 Building the App’s GUI and Resource Files 6.4.1 Adding the Components to the LinearLayout Step 1: Configuring the LinearLayout 6.9 (True/False) You should change the Layout width and Layout height property values from match_parent (which is deprecated) to fill_parent.

ANS: False. You should change the Layout width and Layout height property values from fill_parent (which is deprecated) to match_parent.

Step 2: Adding the Components and Configuring Their Properties Notes on main.xml 6.10 (Self Review) (True/False) ImageView attribute android:adjustViewBounds specifies whether or not the ImageView maintains the aspect ratio of its Drawable.

ANS: True.

6.4.2 Creating the Flag Shake Animation 6.11 (Exercise) An mation.

ANS: animation set.

6.12

is a collection of animations which make up a larger ani-

(Self Review) A

animation moves a View within its parent.

ANS: translate.

6.13 (Exercise) Android supports property of any object.

ANS: property.

6.14

The

animations which allow you to animate any

attribute is the View’s offset when the animation starts.

ANS: android:fromXDelta.

Chapter 6—Flag Quiz Game App: Test Item File

3

6.15 (Exercise) For the android:fromXDelta attribute, specifying the value -5%p indicates that the View should move to the by 5% of the parent’s width (indicated by the p).

ANS: left.

6.16 (True/False) The android:length attribute specifies how long the animation lasts in milliseconds.

ANS: False. The android:duration attribute specifies how long the animation lasts in milliseconds.

6.17 (Self Review) By default, animations in an animation set are applied in parallel, but you can use the attribute to specify the number of milliseconds into the future at which an animation should begin. This can be used to sequence the animations in a set.

ANS: android:startOffset.

6.5 Building the App Instance Variables 6.18

(True/False) The Random object random is the pseudorandom-number generator.

ANS: True.

Overriding Method OnCreate of Class Activity 6.19

Method (inherited indirectly from class ContextWrapper) returns a Resources object (package android.content.res) that can be used to load the Activity’s resources.

ANS: getResources.

resetQuiz Method of Class FlagQuizGame (Our App)

6.20 (Self Review) To access the app’s assets folder’s contents, a method should get the app’s AssetManager by calling method (inherited indirectly from class ContextWrapper).

ANS: get-Assets.

Overriding Method onCreateOptionsMenu of Class Activity 6.21

(True/False) We call Menu’s add method to add Items to a Menu.

ANS: False. We call Menu’s add method to add MenuItems to a Menu.

6.6 AndroidManifest.xml 6.22 (Exercise) We use the theme to the application’s GUI. ANS: android:theme.

6.23 (Self Review) A components.

ANS: theme.

attribute of the application- element to apply a

is a set of styles that specify the appearance of a GUI’s

4

Chapter 6

6.24 (Exercise) (True/False) You can use the android:screenOrientation attribute to specify that an app should always appear in landscape mode (that is, a vertical orientation).

ANS: False. You can use the android:screenOrientation attribute to specify that an app should always appear in portrait mode (that is, a vertical orientation).

6.7 Wrap-Up 6.25

(Self Review) (True/False) You load color and String array resources from the colors.xml and strings.xml files into memory by using the Activity’s Resources object.

ANS: True.

6.26 (Exercise) (True/False) You specify the number of times an animation should repeat with Animation method repeatCount.

ANS: False. You specify the number of times an animation should repeat with Animation method setRepeatCount.

Chapter 7—Cannon Game App: Test Item File

1

Chapter 7—Cannon Game App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

7.3 Technologies Overview Attaching a Custom View to a Layout 7.1

(Self Review) You can create a custom view by extending class View or ANS: one of its subclasses.

.

7.2 (True/False) To add a custom component to a layout’s XML file, you must fully qualify its class name in the XML element that represents the component.

ANS: True.

Activity Lifecycle Methods onPause and onDestroy

7.3 (Exercise) Method is called for the current Activity when another activity receives the focus, which sends the current activity to the background.

ANS: onPause.

7.4 (Self Review) (True/False) One use of onStop is to suspend a game play so that it does not continue executing when the user cannot interact with it.

ANS: False. One use of onPause is to suspend a game play so that it does not continue executing when the user cannot interact with it.

7.5

(Exercise) When an Activity is shut down, its ANS: onDestroy.

method is called.

Overriding Activity Method onTouchEvent 7.6 (Self Review) To process simple touch events for an Activity, you can override class Activity’s onTouchEvent method then use constants from class (package android.view) to test which type of event occurred and process it accordingly.

ANS: MotionEvent.

GestureDetector and SimpleOnGestureListener

(True/False) For more complex gestures, like double taps, you’ll use a GestureDetector (package android.view), which can recognize user actions that represent a series of MotionActivities.

7.7

2

Chapter 7 ANS: False. For more complex gestures, like double taps, you’ll use a GestureDetector (package android.view), which can recognize user actions that represent a series of MotionEvents.

7.8 (Exercise) A allows an app to react to more sophisticated user interactions such as flings, double-taps, long presses and scrolls.

ANS: GestureDetector.

Adding Sound with SoundPool and AudioManager 7.9 An app’s sound effects are managed with a which can be used to load, play and unload sounds.

ANS: SoundPool.

(package android.media),

7.10 (True/False) Sounds are played using one of Android’s several audio streams, which include streams for alarms, DTMF tones, music, notifications, phone rings, system sounds and phone calls.

ANS: True.

7.11 (Self Review) (True/False) The Android documentation recommends that games use the music audio stream to play sounds.

ANS: True.

7.12 (Exercise) We use the Activity’s method to specify that the game’s volume can be controlled with the device’s volume keys and should be the same as the device’s music playback volume. The method receives a constant from class AudioManager (package android.media).

ANS: setVolumeControlStream.

Frame-by-Frame Animation with Threads, SurfaceView and SurfaceHolder 7.13 (Self Review) (True/False) In Android, it’s important to maximize the amount of work you do in the GUI thread to ensure that the GUI remains responsive and does not display ANR (Application Not Responding) dialogs.

ANS: False. In Android, it’s important to minimize the amount of work you do in the GUI thread to ensure that the GUI remains responsive and does not display ANR (Application Not Responding) dialogs.

7.14 (Exercise) Games often require complex logic that should be performed in separate threads of execution and those threads often need to draw to the screen. For such cases, Android provides class —a subclass of View to which any thread can draw.

ANS: SurfaceView.

7.15 (True/False) You manipulate a SurfaceView via an object of class SurfaceHandler, which enables you to obtain a Canvas on which you can draw graphics.

ANS: False. You manipulate a SurfaceView via an object of class SurfaceHolder, which enables you to obtain a Canvas on which you can draw graphics.

7.16 (Exercise) (True/False) Class SurfaceHolder also provides methods that give a thread shared access to the Canvas for drawing, because only one thread at a time can draw to a SurfaceView.

Chapter 7—Cannon Game App: Test Item File

3

ANS: False. Class SurfaceHolder also provides methods that give a thread exclusive access to the Canvas for drawing, because only one thread at a time can draw to a SurfaceView.

7.17 (Self Review) Each SurfaceView subclass should implement the interface , which contains methods that are called when the SurfaceView is created, changed (e.g., its size or orientation changes) or destroyed.

ANS: SurfaceHolder.Callback.

Drawing Graphics Using Paint and Canvas 7.18 We use methods of class lines and circles.

ANS: Canvas.

7.19

(package android.graphics) to draw text,

(Self Review) (True/False) A Canvas draws on a View’s Bitmap.

ANS: True.

7.20 (Exercise) Each drawing method in class Canvas uses an object of class (package android.graphics) to specify drawing characteristics, including color, line thickness, font size and more.

ANS: Paint.

7.4 Building the App’s GUI and Resource Files 7.4.1 strings.xml 7.21 (Self Review) (True/False) Format Strings that contain multiple format specifiers must number the format specifiers for localization purposes.

ANS: True.

7.22 (True/False) The notation 1$ in %1$.1f indicates that the first argument after the format String should delete the format specifier %1$d.

ANS: False. The notation 1$ in %1$.1f indicates that the first argument after the format String should replace the format specifier %1$d.

7.23 (Exercise) %2$.1f indicates that the should replace the format specifier %2$.1f.

ANS: second

argument after the format String

7.24 (Self Review) The d in a format specifier indicates that we’re formatting a decimal integer and the f in a format specifier indicates that we’re formatting a value.

ANS: floating-point.

7.4.2 main.xml 7.25

(True/False) You must fully qualify a custom View’s class name in the layout XML. ANS: True.

4

Chapter 7

7.4.3 Adding the Sounds to the App 7.26

(Self Review) Sound files are stored in the app’s ANS: res/raw.

folder.

7.5 Building the App 7.5.1 CannonGame Subclass of Activity Overriding Activity Method onTouchEvent 7.27 (Exercise) (True/False) A MotionEvent.ACTION_TOUCH indicates that the user touched the screen and indicates that the user moved a finger across the screen ( MotionEvent.ACTION_MOVE).

ANS: False. A MotionEvent.ACTION_DOWN indicates that the user touched the screen and indicates that the user moved a finger across the screen ( MotionEvent.ACTION_MOVE).

7.5.2 CannonView Subclass of View CannonView Constructor

7.28

(Exercise) (True/False) When a View is inflated, its constructor is called and passed a Context and an AttributeSet as arguments.

ANS: True.

7.29 SurfaceView method getHolder returns the corresponding managing the SurfaceView.

ANS: SurfaceHolder.

object for

7.30 (Self Review) (True/False) There are seven sound streams identified by constants in class AudioManager, but the documentation for class SoundPool recommends using the stream for playing music (AudioManager.STREAM_MUSIC) for sound in games.

ANS: True.

7.31 (Exercise) (True/False) SoundPool method start receives three arguments—the application’s Context, a resource ID representing the sound file to load and the sound’s priority.

ANS: False. SoundPool method load receives three arguments—the application’s Context, a resource ID representing the sound file to load and the sound’s priority.

Drawing the Game Elements 7.32 (True/False) The first two arguments to Canvas’s drawCircle method represent the coordinates of the circle’s center. The third argument is the circle’s radius. The last argument is the Paint object specifying the circle’s drawing characteristics.

ANS: True.

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7.6 Wrap-Up 7.33 (Self Review) (True/False) Custom component class names must be fully qualified in the XML layout element that represents the component.

ANS: True.

7.34 (Exercise) Method tivity receives the focus.

ANS: onPause.

7.35

Method

is called for the current Activity when another ac-

is called when the system shuts down an Activity.

ANS: onDestroy.

7.36 (Self Review) You add sound effects to an app’s them with a SoundPool.

ANS: res/raw.

7.37

Use the system’s

folder and manage

service to obtain the device’s current music volume.

ANS: AudioManager.

7.38 (Exercise) (True/False) When a game loop controls a game based on the amount of time that has elapsed between animation frames, the game will operate at different speeds as appropriate for each device.

ANS: False. When a game loop controls a game based on the amount of time that has elapsed between animation frames, the game will operate at the same overall speed on all devices.

Chapter 8—SpotOn Game App: Test Item File

1

Chapter 8—SpotOn Game App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

8.3 Technologies Overview Android 3.x and Property Animation 8.1

(Exercise) View animations allow you to change limited aspects of a View’s appearance, such as where it’s displayed, its rotation and its size.

ANS: Tweened.

8.2

(Self Review) ANS: Frame.

View animations display a sequence of images.

8.3 (Exercise) With animation (package android.animation), you can animate any property of any object—the mechanism is not limited to Views.

ANS: property.

8.4 (True/False) Moving a Button with property animation not only draws the Button in a different location on the screen, it also ensures that the user can continue to interact with that Button in its current location.

ANS: True.

8.5 Property animations animate values over time. To create an animation you specify the target object containing the property or properties to animate, the animation’s duration, the values to animate between for each property and how to change the property values over time—known as an .

ANS: interpolator.

8.6 (Self Review) (True/False) The property animation class PropertyAnimator calculates property values over time, but you must specify an AnimatorUpdateListener in which you programmatically modify the target object’s property values.

ANS: False. The property animation class ValueAnimator calculates property values over time, but you must specify an AnimatorUpdateListener in which you programmatically modify the target object’s property values.

8.7 (Exercise) ValueAnimator subclass uses the target object’s set methods to modify the object’s animated properties as their values change over time.

ANS: ObjectAnimator.

2

Chapter 8

8.8

(Self Review) (True/False) Android 3.1 added the utility class ViewPropertyAnimator to simplify property animation for Views and to allow multiple properties to be animated in sequence.

ANS: False. Android 3.1 added the new utility class ViewPropertyAnimator to simplify property animation for Views and to allow multiple properties to be animated in parallel.

8.9

(True/False) Each View now contains an animate method that returns a ViewPropertyAnimator on which you can chain method calls to configure the animation. When the last method call in the chain completes execution, the animation starts.

ANS: True.

Listening for Animation Lifecycle Events 8.10 (Self Review) You can listen for property-animation lifecycle events by implementing the interface , which defines methods that are called when an animation starts, ends, repeats or is canceled.

ANS: AnimatorListener-.

ConcurrentLinkedQueue and Queue

8.11

(Exercise) You can use the ConcurrentLinkedQueue class (from package java.util.concurrent) and the Queue interface to maintain lists of objects that can be accessed from multiple threads of execution in parallel.

ANS: thread-safe.

8.4 Building the App’s GUI and Resource Files 8.4.1 AndroidManifest.xml 8.12 (True/False) When you set the uses-sdk element’s android-:minSdkVersion attribute to "10", your app will run only on Android 3.1+ devices and AVDs. ANS: False. When you set the uses-sdk element’s android-:minSdkVersion attribute to "12", your app will run only on Android 3.1+ devices and AVDs. 8.13 (Exercise) Setting the attribute android:hardwareAccelerated to "true" allows the app to use hardware accelerated , if available, for performance.

ANS: graphics.

8.5 Building the App 8.5.1 SpotOn Subclass of Activity 8.14 (Self Review) (True/False) When an Activity begins executing, its onCreate method is called. This is followed by calls to the Activity’s onPause then onResume methods. Method onResume is also called when an Activity in the background returns to the foreground.

Chapter 8—SpotOn Game App: Test Item File

3

ANS: False. When an Activity begins executing, its onCreate method is called.

This is followed by calls to the Activity’s onStart then onResume methods.

Method onResume is also called when an Activity in the background returns to

the foreground.

8.5.2 SpotOnView Subclass of View Methods pause, cancelAnimations and resume 8.15 (True/False) Method cancelAnimations iterates through the animators collection and calls method stop on each Animator. This immediately terminates each animation and calls its AnimationListener’s onAnimationCancel and onAnimationEnd methods.

ANS: False. Method cancelAnimations iterates through the animators collection and calls method cancel- on each Animator. This immediately terminates each animation and calls its AnimationListener’s onAnimationCancel and onAnimationEnd methods.

Method addNewSpot 8.16 (Self Review) A configures animations for commonly animated View properties—alpha (transparency), rotation, scale, translation (moving relative to the current location) and location.

ANS: ViewPropertyAnimator.

8.17 (Exercise) In addition, a ViewPropertyAnimator provides methods for setting an animation’s duration, (to respond to animation lifecycle events) and TimeInterpolator (to determine how property values are calculated throughout the animation).

ANS: AnimatorListener.

8.6 Wrap-Up 8.18 Android versions prior to 3.0 had two animation mechanisms—tweened View animations that allow you to change limited aspects of a View’s appearance and animations that display a sequence of images.

ANS: frame View.

8.19 (Exercise) (True/False) Property animations can be used to animate any property of any object.

ANS: True.

8.20 (True/False) Property animations animate values over time and require a target object containing the property or properties to animate, the length of the animation, the values to animate between for each property and how to change the property values over time.

ANS: True.

8.21 (Self Review) Android 3.1’s utility class ViewPropertyAnimator was added to the animation APIs to simplify property animation for Views and to allow animation of multiple properties in .

ANS: parallel.

4

Chapter 8

8.22 You listen for property-animation lifecycle events by implementing the interface , which defines methods that are called when an animation starts, ends, repeats or is canceled.

ANS: AnimatorUpdateListener-.

8.23 (Exercise) (True/False) You can use the ConcurrentLinkedQueue class from package java.util.concurrent and the Queue interface to maintain thread-safe lists of objects that can be accessed from multiple threads of execution in parallel.

ANS: True.

1

Chapter 9

Chapter 9—Doodlz App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

9.3 Technologies Overview Enabling an App to Integrate Better with Android 3.0 and Higher 9.1

(Self Review) Android 3.0’s look-and-feel is called the ANS: holographic theme.

.

Using SensorManager to Listen for Accelerometer Events 9.2 (Exercise) Most Android devices have an movement.

ANS: accelerometer.

that allows apps to detect

9.3 (True/False) Gravity, gyroscope, light, linear acceleration, magnetic field, pressure, proximity, rotation vector and temperature are all examples of sensors supported by one or more Android devices.

ANS: True.

9.4 To listen for sensor events, you get a reference to the system’s which enables the app to receive data from the device’s sensors.

ANS: SensorManager.

service,

9.5 (Self Review) You use the SensorManager to register the sensor changes that your app should receive and to specify the that will handle those sensor-change events.

ANS: SensorEventListener.

AtomicBoolean

9.6

(Exercise) (True/False) In Android, sensor events are handled in the GUI thread.

ANS: False. In Android, sensor events are handled in a separate thread of execution from GUI events.

9.7 An AtomicBoolean manages a boolean value in a thread-safe manner, so that it can be accessed from .

ANS: multiple threads of execution.

2

Chapter 9

Custom Colors 9.8 (Exercise) (True/False) The alpha component specifies the Color’s transparency with 0 representing completely transparent and 100 representing completely opaque.

ANS: False. The alpha component specifies the Color’s transparency with 0 representing completely transparent and 255 representing completely opaque.

Processing Touch Events 9.9 (Self Review) A Path object (package android-.graphics) represents a geometric path consisting of line segments and .

ANS: curves.

9.10 (True/False) Touch events are processed by overriding the View method OnGesture.

This method receives a Motion-Event (package android.view) that contains the type of touch event that occurred and the ID of the finger (i.e., pointer) that generated the event.

ANS: False. Touch events are processed by overriding the View method OnTouchEvent. This method receives a Motion-Event (package android.view) that contains the type of touch event that occurred and the ID of the finger (i.e., pointer) that generated the event.

9.11 (Self Review) We use the type of the touch event to determine whether the user has touched the screen, or lifted a finger from the screen.

ANS: dragged across the screen.

Using Toasts to Display a Message for a Short Time 9.12 (Exercise) A (package android-.widget) displays a message for a short time, then disappears from the screen.

ANS: Toast.

9.4 Building the App’s GUI and Resource Files 9.4.1 AndroidManifest.xml In this app, we set the uses-sdk element’s android:targetSdkVersion attribute to "11", which represents the Android 3.0 SDK. If this app is installed on a device running An9.13

droid 3.0 or higher, Android- 3.0’s theme will be applied to the app’s GUI components, and the menu items will be placed at the right side of the app’s action bar, which appears at the top of the screen on tablet devices.

ANS: holographic.

9.14 (True/False) Setting the android:targetSdkVersion attribute to "11" has no effect when the app is installed on a device running an earlier version of Android.

ANS: True.

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9.4.2 color_dialog.xml 9.15 (Self Review) (True/False) We use the standard SeekBar thumb in our apps, but you can customize it by setting the SeekBar’s android-:seekBar attribute to a drawable resource, such as an image.

ANS: False. We use the standard SeekBar thumb in our apps, but you can customize it by setting the SeekBar’s android-:thumb attribute to a drawable resource, such as an image.

9.5 Building the App 9.5.1 Doodlz Subclass of Activity Instance Variables and Constants 9.16

(Exercise) The

monitors the accelerometer to detect device movement.

ANS: sensorManager.

Overriding Activity- Methods onCreate and onPause 9.17 (Exercise) SensorManager’s gravity on earth.

ANS: GRAVITY_EARTH. 9.18 Method events.

constant represents the acceleration due to

to configures the SensorManager to listen for accelerometer

ANS: enableAccelerometerListening.

9.19 (Self Review) (True/False) You unregister the accelerometer event handler when the app is sent to the foreground.

ANS: False. You unregister the accelerometer event handler when the app is sent to the background.

Methods enableAccelerometerListening and disableAccelerometerListening 9.20

Android’s

service enables the app to interact with the device’s sensors.

ANS: SensorManager

(Exercise) We register to receive accelerometer events using SensorManager’s registerListener method, which receives three arguments: the SensorEventListener object that will respond to the events, a Sensor representing the type of sensor data the app wishes to 9.21

receive and

.

ANS: a rate at which sensor events should be delivered to the app

9.22 (Self Review) Use class SensorManager’s accelerometer events.

ANS: unregisterListener.

method to stop listening for

4

Chapter 9

Anonymous Inner Class That Implements Interface SensorEventListener to Process Accelerometer Events 9.23 (Self Review) Override SensorEventListener method celerometer events.

ANS: onSensorChanged.

to process ac-

9.24

(Exercise) (True/False) For accelerometer events, the SensorEvent parameter values array contains three elements representing the acceleration (in meter/second 2 ) in the x (left/right), y (up/down) and z (forward/backward) directions.

ANS: True.

Method showColorDialog 9.25 Color’s static methods ARGB values from the current color.

ANS: alpha-.

, red, green and blue are used to extract the

Anonymous Inner Class That Implements Interface OnSeekBarChangeListener to Respond to the Events of the alpha, red, green and blue SeekBars 9.26 (Exercise) (True/False) Method onProgressChanged is called once when the user drags a SeekBar’s thumb.

ANS: False. Method onProgressChanged is called frequently when the user drags a SeekBar’s thumb.

Anonymous Inner Class That Implements Interface OnClickListener to Set the New Drawing Color 9.27

(Self Review) Use Dialog’s ANS: dismiss.

method to close a dialog.

Anonymous Inner Class That Implements Interface OnSeekBarChangeListener to Respond to the Events of the widthSeekBar 9.28 (True/False) Class Paint’s setStrokeCap method specifies the appearance of the top of the line.

ANS: False. Class Paint’s setStrokeCap method specifies the appearance of the line ends.

9.5.2 DoodleView Subclass of View DoodleView Fields, Constructor and onSizeChanged Method

9.29 (Exercise) We pass true to Paint’s which smooths the edges of the lines.

ANS: setAntiAlias.

method to enable anti-aliasing

Chapter 9—Doodlz App: Test Item File

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Methods clear, setDrawingColor, getDrawingColor, setLineWidth and getLineWidth of Class DoodleView9.30 (Self Review) (True/False) Call the inherited View method validate to indicate that the View needs to be redrawn.

ANS: False. Call the inherited View method invalidate to indicate that the View needs to be redrawn.

9.31 Paint’s setColor method receives an int that represents the new color in format.

ANS: ARGB. sets paintLine’s stroke width to the specified num-

9.32 (Exercise) Method ber of pixels.

ANS: setLineWidth.

Overriding View Method OnDraw 9.33

(Self Review) When a View needs to be redrawn, it’s ANS: onDraw.

method is called.

Overriding View Method onTouchEvent 9.34

Method

is called when the View receives a touch event.

ANS: OnTouchEvent.

9.35 (Exercise) Android supports the screen.

ANS: multitouch.

—that is, having multiple fingers touching

(Self Review) Motion-Event’s method returns an int representing the MotionEvent type, which you can use with constants from class MotionEvent to determine 9.36

how to handle each event.

ANS: getActionMasked.

9.37 Motion-Event’s method returns an integer index representing which finger caused the event. This index is not the finger’s unique ID—it’s simply the index at which that finger’s information is located in this MotionEvent object.

ANS: getActionIndex.

(Exercise) (True/False) To get the finger’s unique ID that persists across MotionEvents until the user removes that finger from the screen, we’ll use Motion-Event’s getID 9.38

method, passing the finger index as an argument.

ANS: False. To get the finger’s unique ID that persists across MotionEvents until the user removes that finger from the screen, we’ll use Motion-Event’s getPointerID method, passing the finger index as an argument.

9.39

(Self Review) (True/False) If the action is MotionEvent.ACTION_DOWN or MotionEvent.ACTION_POINTER_DOWN, the user touched the screen with the same finger.

ANS: False.

If the action is MotionEvent.ACTION_DOWN or MotionEvent.ACTION_POINTER_DOWN, the user touched the screen with a new finger.

6

Chapter 9

9.40 The first finger to touch the screen generates a MotionEvent.ACTION_DOWN event, and all other fingers generate events.

ANS: MotionEvent.ACTION_POINTER_DOWN. touchMoved Method of Class DoodleView

9.41 (Self Review) The utility method more fingers across the screen.

ANS: touchMoved.

is called when the user moves one or

9.42 (Exercise) (True/False) The system MotionEvent passed from onTouchEvent contains touch information for multiple moves on the screen if they occur at the same time.

ANS: True.

9.43 MotionEvent method describes.

returns the number of touches this Motion-Event

ANS: getPointerCount.

9.44 Use Path’s method to add a geometric curve (specifically a quadratic bezier curve) from the previous Point to the new Point.

ANS: quadTo. touchEnded Method of Class DoodleView

9.45 (Exercise) The utility method is called when the user lifts a finger from the screen. The method receives the ID of the finger (lineID) for which the touch just ended as an argument.

ANS: touchEnded.

9.46 (Self Review) (True/False) Resetting the Path erases its corresponding painted line from the screen, because those lines have already been drawn to the bitmap that’s displayed to the screen.

ANS: False. Resetting the Path does not erase its corresponding painted line from the screen, because those lines have already been drawn to the bitmap that’s displayed to the screen. saveImage Method

9.47 (True/False) ContentValues method add adds a key-value pair to a ContentValues object.

ANS: False. ContentValues method put adds a key-value pair to a ContentValues object.

9.48 (Self Review) Toast method receives as arguments the Context on which the Toast is displayed, the message to display and the duration for which the Toast will be displayed.

ANS: makeText.

9.49 (Exercise) (True/False) Toast method setLocation specifies where the Toast will appear. The constant Gravity.CENTER indicates that the Toast should be centered over the coordinates specified by the method’s second and third arguments. Toast method show displays the Toast.

ANS: False. Toast method setGravity specifies where the Toast will appear. The constant Gravity.CENTER indicates that the Toast should be centered over the

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7

coordinates specified by the method’s second and third arguments. Toast method show displays the Toast.

9.6 Wrap-Up 9.50 (Exercise) (True/False) Use a ToastMessage to display a message that automatically disappears after a short period of time.

ANS: True.

Chapter 10—AddressBook App: Test Item File Instructor Note

1

Chapter 10—AddressBook App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

10.3 Technologies Overview Specifying Additional activity Elements in the App’s Manifest 10.1 (Self Review) (True/False) The AndroidManifest.xml file describes an app’s components.

ANS: True.

10.2

(Exercise) (True/False) Each Activity must be described in the app’s manifest.

ANS: True.

Defining Styles and Applying Them to GUI Components 10.3 You can define common GUI component attribute–value pairs as XML .

You can then apply the styles to all components that share those values by using the style attribute. Any subsequent changes you make to a style are automatically applied to all GUI components that use the style.

ANS: style resources.

Extending Class ListActivity to Create an Activity That Contains a ListView 10.4 (True/False) When an Activity’s primary task is to display a scrollable list of items, you can extend class ListActivity (package android.app), which uses a ListView that occupies the entire screen as its default layout.

ANS: True.

Manipulating a SQLite Database 10.5 (Self Review) (True/False) SQLite (www.sqlite.org) is the world’s most widely deployed database engine.

ANS: True.

10.6

(Exercise) SQLite database query results are managed via a

android-.database).

ANS: Cursor

(package

2

Chapter 10

Using Multithreading to Perform Database Operations Outside the GUI Thread 10.7 (Self Review) (True/False) It’s good practice to perform long running operations or operations that block execution until they complete (e.g., file and database access) in the GUI thread.

ANS: False. It’s good practice to perform long running operations or operations that block execution until they complete (e.g., file and database access) outside the GUI thread.

10.8 (Exercise) When we need a database operation’s results in the GUI thread, we’ll use an (package android.os) to perform the operation in one thread and receive the results in the GUI thread.

ANS: AsyncTask.

10.4 Building the GUI and Resource Files 10.4.1 AddEditContact Activity’s Layout: add_contact.xml 10.9 For devices that display a soft keyboard, the attribute (in the layout’s XML file) specifies which keyboard to display when the user touches the corresponding EditText.

ANS: android:inputType.

10.4.2 Defining the App’s MenuItems with menu Resources in XML 10.10 (Exercise) (True/False) Resource files that define menus are placed in the app’s res/menu folder (which you must create) and are added to the project like other resourcefiles, but in the New Android XML File dialog you select Menu as the resource type.

ANS: True.

10.11 (Self Review) (True/False) Each menu resource XML file contains a root menu element with nested item elements that represent each MenuItem.

ANS: True.

10.12 (True/False) android:alphabeticShortcut specifies a letter that the user can press on a hard keyboard to select the menu item.

ANS: True.

Chapter 10—AddressBook App: Test Item File Instructor Note

3

10.5 Building the App 10.5.1 AddressBook Subclass of ListActivity Overriding Activity Method onCreate 10.13 (Self Review) (True/False) SimpleCursorAdapter is a subclass of CursorAdapter that’s designed to simplify mapping Cursor columns directly to TextViews or ImagesViews defined in your XML layouts.

ANS: True.

10.14 (True/False) To create a SimpleCursorAdapter, you must first define arrays containing the column names to map to GUI components and the resource IDs of the GUI components that will display the data from the named columns.

ANS: True.

Overriding Activity Methods onResume and onStop 10.15 (Exercise) Method is called each time an Activity returns to the foreground, including when the Activity is first created.

ANS: onResume.

10.16 (Self Review) Activity method is called when the Activity is no longer visible to the user—typically because another Activity has started or returned to the foreground.

ANS: onStop.

10.17 Cursor method ANS:

releases resources used by the Cursor.

deactivate

GetContactsTask Subclass of AsyncTask

10.18 (Exercise) (True/False) A key benefit of using an SyncTask is that it handles the details of creating threads and executing its methods on the appropriate threads for you, so that you do not have to interact with the threading mechanism directly.

ANS: False. A key benefit of using an AsyncTask is that it handles the details of creating threads and executing its methods on the appropriate threads for you, so that you do not have to interact with the threading mechanism directly.

Managing Cursors 10.19 Class Activity can also manage Cursors for you. Activity method the Activity to manage the Cursor’s lifecycle based on the Activity’s lifecycle.

ANS: startManagingCursor.

tells

10.20 (Self Review) (True/False) When an Activity is stopped, it will call deactivate on any Cursors it’s currently managing. When the Activity resumes, it will call requery on its Cursors. When the Activity is destroyed, it will automatically call close to release all resources held by any managed Cursors.

ANS: True.

4

Chapter 10

10.21 (Exercise) (True/False) A deactivated Cursor consumes more resources than an active one, so it’s good practice to align your Cursor’s lifecycle with its parent Activity if the Cursor is not shared among multiple Activity objects.

ANS: False. A deactivated Cursor consumes less resources than an active one, so it’s good practice to align your Cursor’s lifecycle with its parent Activity if the Cursor is not shared among multiple Activity objects.

10.22 (Exercise) (True/False) Allowing your Activity to manage the Cursor’s lifecycle also ensures that the Cursor will be closed when it’s no longer needed.

ANS: True.

Overriding Activity Methods onCreateOptionsMenu and onOptionsItemSelected

10.23 (Self ty’s

Review) You method.

obtain

the

MenuInflater

by

calling

Activi-

ANS: getMenuInflater.

Anonymous Inner Class That Implements Interface OnItemClickListener to Process ListView Events 10.24 You can pass data between activities by adding extras to the Intent using Intent’s method.

ANS: put-Extra.

10.5.2 ViewContact Subclass of Activity Overriding Activity Methods onCreate and onResume 10.25 (Exercise) Activity method getIntent returns the Intent that launched the Activity. We use that to call Intent method , which returns a Bundle that contains any key–value pairs that were added to the Intent as extras.

ANS: getExtras.

GetContactsTask Subclass of AsyncTask

10.26 (Self Review) (True/False) It’s considered good practice to ensure that Cursor method moveToFirst returns false before attempting to get data from the Cursor.

ANS: False. It’s considered good practice to ensure that Cursor method moveToFirst returns true before attempting to get data from the Cursor.

10.27 Class Cursor also provides method when the specified column name does not exist.

ANS: getColumnIndexOrThrow.

if you prefer to get an exception

10.28 (Self Review) (True/False) It’s good practice to release resources like database connections when they are not being used so that other activities can use the resources.

ANS: True.

Chapter 10—AddressBook App: Test Item File Instructor Note

5

10.5.3 DatabaseConnector Utility Class Methods insertContact, updateContact, getAllContacts, getOneContact and deleteContact 10.29 (Exercise) The Cursor returned by method query contains all the table rows that match the method’s arguments—the so-called .

ANS: result set.

10.30 The Cursor is positioned before the first row of the result set—Cursor’s various methods can be used to move the Cursor through the result set for processing.

ANS: move.

10.6 Wrap-Up 10.31 (True/False) ListView is a subclass of AdapterView, which allows a component to be bound to a data source CursorAdapter to display the results of a database query in main Activity’s ListView.

ANS: True.

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Chapter 11

Chapter 11—Route Tracker App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

11.2 Test-Driving the Route Tracker App Obtaining a Google Maps API Key 11.1 (Self Review) (True/False) To create your own app using the Google Maps API, you’ll need to obtain a unique API key from Google.

ANS: True.

11.2 (Exercise) (True/False) Apps must be signed with a digital certificate before they can be installed on a device. When you’re building and testing apps, the ADT Plugin handles this automatically by creating a debug certificate and using it to sign your apps.

ANS: True.

Sending GPS Data to an AVD with GPX Files 11.3 The Android emulator enables you to send GPS data to an AVD, so you can test your location-based apps without an actual Android device. To do so, you use a file containing GPS data in Format. Such files typically end with the .gpx extension and are called GPX files.

ANS: GPS Exchange.

11.3 Technologies Overview New Features in AndroidManifest.xml 11.4 (Exercise) To access a nonstandard library—that is, one that’s not included with the core Android APIs, such as the Google Maps API—you must indicate the library’s name in the app’s manifest with a element nested in the application element.

ANS: uses-library.

11.5 (Self Review) (True/False) If you’d like your app to use most of the screen to display maps, you can hide the title bar by using one of the standard Android themes, which can be specified with the attribute android:theme in the activity element. A theme changes the look-and-feel of an app’s GUI. ANS: True.

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Chapter 11

11.6

(True/False) By default, shared Android services are accessible to an app.

ANS: False. By default, shared Android services are not accessible to an app.

11.7 (Self Review) (True/False) Shared Android services include those that allow an app to change power settings, obtain location data, control whether a device is allowed to sleep, and more.

ANS: True.

11.8 (Exercise) To access shared Android services, you must request permission to use them in the manifest file with elements nested in the root manifest element.

When a user prepares to install an app, the operating system tells the user which permissions are being requested and asks the user to confirm whether they should be granted. If not, the app will not be installed.

ANS: uses-permission.

Classes MapActivity, MapView and Overlay 11.9 Package Maps API.

contains the classes that we used to interact with the Google

ANS: com.google.android.maps.

11.10 (Self Review) (True/False) MapViews support gestures to zoom and pan the map—any additional functionality must be added programmatically.

ANS: True.

11.11 (Exercise) To display data on a MapView, such as the line representing the route in this app, you create a subclass of and override its draw method.

ANS: Overlay.

Location Data 11.12 Package tion data.

contains the classes and interfaces for acquiring and using loca-

ANS: android.location.

11.13 (Self Review) Class

provides access to the device’s location services.

ANS: LocationManager.

11.14 (Exercise) (True/False) Depending on your device, several location providers may be supported—LocationManager provides capabilities for choosing the best one based on your app’s requirements, which you specify in a Requirements object.

ANS: False. Depending on your device, several location providers may be supported—LocationManager provides capabilities for choosing the best one based on your app’s requirements, which you specify in a Criteria object.

11.15 (True/False) The settings that can be specified in a Criteria are accuracy, battery usage, bearing, speed, altitude and the monetary cost of the provider.

ANS: True.

11.16 (Exercise) Once you have a location provider, you can request updates from it and have them delivered to a LocationListener. The updates are delivered to the listener as objects that represent the device’s geographic location—these include latitude and longitude data, the time they were recorded and, depending on the location provider, may also include altitude and speed data (some devices don’t have sensors for these).

ANS: Location.

Chapter 11—Route Tracker App: Test Item File Instructor Note

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11.17 (Self Review) To determine when the device has a GPS fix—that is, the device has “locked onto” enough GPS satellites to receive GPS data for tracking—we implement the interface.

ANS: GpsStatus.Listener.

Classes PowerManager and WakeLock 11.18 Class an Android device.

(package android.os) enables an app to control the power state of

ANS: PowerManager.

11.19 (Exercise) (True/False) An app that changes the power settings can negatively affect the device’s battery life when the app is executing, so class PowerManager should be used frequently.

ANS: False. An app that changes the power settings can negatively affect the device’s battery life when the app is executing, so class PowerManager should be used sparingly.

Programmatically Determining the Device’s Display Size 11.20 (Self Review) Class device’s screen dimensions.

ANS: Display.

(package android.view) provide’s access to the

11.4 Building the GUI and Resource Files 11.4.1 AndroidManifest.xml Hiding the App’s Title Bar 11.21 You can use the attribute in the activity element to change the Activity’s theme to Theme.Black.NoTitleBar—a variation of the standard Android theme that simply hides the Activity’s title bar.

ANS: android:theme.

Requesting App Permissions 11.22 (Self Review) The permission access to download map and satellite images.

: indicates that this app requires Internet

ANS: android.permission.INTERNET.

11.23 (Exercise) (True/False) The permission android.permission.WAKE_LOCK indicates that this app needs access to the PowerManager to prevent the device from sleeping while the app is tracking a route.

ANS: True.

11.4.2 Route Tracker Layout: main.xml 11.24 (True/False) Components are positioned in the FrameLayout’s upper-right corner, unless the gravity property is used to position them.

4

Chapter 11 ANS: False. Components are positioned in the FrameLayout’s upper-left corner, unless the gravity property is used to position them.

11.25 (True/False) The ToggleButton attributes android:textTrue and android:textFalse enable you to specify the text to display on the button in the on and off states, respectively.

ANS: False. The ToggleButton attributes android:textOn and android:textOff enable you to specify the text to display on the button in the on and off states, respectively.

11.5 Building the App 11.5.1 RouteTracker Subclass of MapActivity Overriding Activity Method onCreate 11.26 (Self Review) You use a to programmatically zoom in and out of a map and to change the geographic location appearing centered in the MapView.

ANS: MapController

Overriding Activity Methods onStart and onStop 11.27 (Exercise) (True/False) High-accuracy GPS data uses less power. If your app doesn’t require such accuracy, you can choose Criteria.ACCURACY_COARSE. ANS: False. High-accuracy GPS data uses more power. If your app doesn’t require such accuracy, you can choose Criteria.ACCURACY_COARSE. 11.28 We use the LocationManager’s GpsStatus.Lisener to determine when the device has a GPS —that is, the device has “locked onto” enough GPS satellites to receive GPS data for tracking.

ANS: fix.

11.29 (Self Review) (True/False) LocationManager’s getBestProvider method returns a String representing the name of the location provider that best meets the given Criteria.

The true argument indicates that only an enabled provider should be returned.

ANS: True.

11.30 (Exercise) Many GPS-based apps use LocationManager’s method to get the location that was last reported when the device previously had a GPS fix (such as during a previous execution of the app).

ANS: getLastKnownLocation.

Method updateLocation 11.31 (Exercise) (True/False) A GeoPoint consists of a latitude and longitude measured in degrees.

ANS: False. A GeoPoint consists of a latitude and longitude measured in microdegrees (millionths of a degree).

11.32 (Self Review) MapController’s the given GeoPoint using a smooth animation.

method moves the center of the map to

Chapter 11—Route Tracker App: Test Item File Instructor Note

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ANS: animateTo.

Anonymous LocationListener Class to Respond to LocationManager Events 11.33 LocationListeners receive events from the when the device’s physical location changes and when the location provider’s status changes.

ANS: LocationManager.

11.5.2 BearingFrameLayout Subclass of FrameLayout Method getChildLayoutParams 11.34 Class provides the size of the screen as well as its refresh rate and current orientation; its getWidth and getHeight methods return the dimensions of the screen.

ANS: Display.

Overriding View Method dispatchDraw 11.35 (Self Review) You override View method should be displayed.

ANS: dispatchDraw.

to control how child Views

11.6 Wrap-Up 11.36 (Exercise) Class LocationManager provides access to the device’s location services and chooses the best location provider based on the requirements you specify in a object. To determine when the device has a GPS fix, you implement the GpsStatus.Listener interface.

ANS: Criteria.

11.37 (Self Review) (True/False) Class PowerManager enables the app to control a device’s power state so that, for example, the app can record location data even if the screen is off.

ANS: True.

Instructor Note

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Chapter 12—--Slideshow App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

12.3 Technologies Overview Launching Intents That Use Built-In Content Providers 12.1

(True/False) Android provides storage that can be shared by all applications.

ANS: False. Android does not provide storage that can be shared by all applications.

12.2 (Exercise) Android uses make data accessible across applications.

ANS: content providers.

that enable apps to save and retrieve data and to

12.3 (Self Review) (True/False) Several BroadcastReceivers are built into Android for access to data such as images, audio, video, contact information and more.

ANS: False. Several content providers are built into Android for access to data such as images, audio, video, contact information and more.

Customizing the Layout for a ListActivity (True/False) When replacing a ListActivity’s default layout, you must define a ListView in the layout and you must assign its android-:id attribute the value "@android:id/list".

ANS: True.

12.4

Launch an Intent That Returns a Result 12.5 (Self Review) Activity method enables an Activity to be notified when another Activity completes execution and to receive results back from the completed Activity.

ANS: startActivityForResult.

ArrayAdapter for a ListView

View-Holder Pattern 12.6 (Exercise) (True/False) Creating custom ListView items is a cost effective runtime operation, even for large lists with complex list-item layouts.

2

Chapter 12 ANS: False. Creating custom ListView items is an expensive runtime operation, es-

pecially for large lists with complex list-item layouts.

12.7 (Exercise) When you scroll in a ListView, as items scroll off the screen, Android reuses those list items for the new ones that are scrolling onto the screen. You can take advantage of the existing GUI components in the reused list items to increase a ListView’s performance of your ListViews. To do this, use the pattern.

ANS: view-holder.

Notifying a ListView When Its Data Source Changes 12.8 its

(Self Review) When the ArrayAdapter’s data set changes, you can call method to indicate that the Adapter’s underlying data set has changed.

ANS: notifyDataSetChanged.

Playing Music with a MediaPlayer 12.9 A (package android.media) enables an app to play audio or video from files stored on the device or from streams over a network.

ANS: MediaPlayer.

Loading Images with BitmapFactory 12.10 (Exercise) A

(package android.graphics) creates Bitmap objects.

ANS: BitmapFactory.

12.11 (Self Review) You images to save memory; This helps prevent out-of-memory errors, which can be common when manipulating many Bitmaps.

ANS: downsample.

Cross Fading Between Images with TransitionDrawable and BitmapDrawable 12.12 (True/False) A TransitionDrawable provides a built-in animation that transitions between two Drawable objects.

ANS: True.

12.4 Building the GUI and Resource Files 12.4.1 Using Standard Android Icons in the App’s GUI 12.13 (True/False) Android provides standard icons that you can use in your own apps; These are located in the SDK’s platforms folder under each platform version’s data/res/drawable-hdpi folder.

ANS: True.

12.4.2 Layout for the EditText in the Set Slideshow Name Dialog 12.14 (Self Review) (True/False) Setting the android:singleLine attribute to false allows only a single line of text in an element.

Instructor Note

3

ANS: False. Setting the android:singleLine attribute to true allows only a single

line of text in an element.

12.5 Building the App 12.5.1 Slideshow Subclass of ListActivity Overriding Activity Methods onCreateOptionsMenu, onOptionsItemSelected and onActivityResult

12.15 (Exercise) In general, you should wrap calls to startActivity and startActivityForResult in a try statement, so you can catch the exception if there is no Activity to handle the .

ANS: Intent.

12.5.2 SlideshowEditor Subclass of ListActivity Overriding Activity Method onActivityResult 12.16 (Exercise) (True/False) Method onActivityResult is called when a sub-Activity started by the startActivityForResult method finishes executing.

ANS: True.

OnClickListener addPictureButtonListener for addPictureButton’s Click Event

12.17 (Self Review) Intent with Intent’s ACTION_GET_CONTENT constant indicates that the Intent allows the user to select content that’s stored .

ANS: on the device.

12.18 Intent method createChooser returns the specified Intent as one of type android-.intent.action.CHOOSER, which displays an Activity chooser that allows the user to select which Activity to use for choosing an image if .

ANS: more than one Activity on the device supports this.

OnClickListener addMusicButtonListener for addMusicButton’s Click Event

12.19 (Self Review) An Intent that uses the MIME type " select any type of audio on the device.

ANS: audio/*.

" to allows the user to

12.5.3 SlideshowPlayer Subclass of ListActivity package and import Statements, and Fields of Class SlideshowPlayer

12.20 (Exercise) State information is saved in onSaveInstance-State and loaded in when the Activity goes to the background and returns to the foreground, respectively.

ANS: onCreate.

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Chapter 12

Overriding Activity Method onCreate 12.21 MediaPlayer’s prepare method prepares the MediaPlayer for ANS: playback.

.

12.22 (True/False) If playing a streaming media file, it’s recommended that you use the prepare-Async method, which returns immediately; otherwise, prepare will block the current thread until the stream has been buffered.

ANS: True.

12.23 (Self Review) Method prepare will if the MediaPlayer cannot be prepared—for example, if it’s currently playing a media clip.

ANS: throw an exception.

12.24 (Exercise) (True/False) Calling MediaPlayer’s setLooping method with the argument true loops playback if the music’s duration is longer than the total slideshow duration.

ANS: False. Calling MediaPlayer’s setLooping method with the argument true loops playback if the music’s duration is shorter than the total slideshow duration.

12.25 (Self Review) Calling MediaPlayer’s to the specified time in milliseconds.

ANS: seekTo.

method moves the audio playback

12.6 Wrap-Up 12.26 (Exercise) (True/False) Use the view-holder pattern to boost the performance of ListViews with complex list-item layouts.

ANS: True.

Chapter 13—Enhanced Slideshow App: Test Item File Instructor Note

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Chapter 13—Enhanced Slideshow App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

13.3 Technologies Overview File Processing and Object Serialization 13.1 (Self Review) A serialized object is represented as a sequence of bytes that includes the object’s data and information about the object’s type.

ANS: True.

13.2

The serialization capabilities are located in package ANS: java.io.

.

13.3 (Exercise) To use an object with the serialization mechanism, the object’s class must implement the interface, which is a tagging interface.

ANS: Serializable.

13.4

(True/False) A tagging interface contains a tagging method.

ANS: False. A tagging interface does not contain methods.

13.5 (Self Review) (True/False) Objects of a class that implements Serializable are tagged as being Serializable objects—that is, any object of a class that implements Serializable is a Serializable object.

ANS: True.

13.6 (Exercise) A serialized object can be read from a file and —that is, the type information and bytes that represent the object and its data can be used to recreate the object graph in memory. This is accomplished with an ObjectInputStream that reads the bytes from a specified InputStream.

ANS: deserialized.

13.7 (Exercise) ObjectOutputStream’s method returns the deserialized object as type Object. To use it in an app, you must cast the object to the appropriate type.

ANS: readObject.

Playing Videos with a VideoView 13.8

(Self Review) Use a ANS: Video-View.

to play videos.

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Chapter 13

13.9

Use

(package android-.widget) to provide video playback controls.

ANS: MediaController.

13.10 (Self Review) (True/False) The VideoView maintains its own MediaPlayer- to play the video.

ANS: True.

13.11 (Exercise) (True/False) You can use a MediaPlayer.OnFinishListener to determine when a video finishes playing so we can continue playing.

ANS: False. You can use a MediaPlayer.OnCompletionListener to determine when a video finishes playing so we can continue playing.

13.4 Building the App 13.4.1 Slideshow Class Overriding Activity Method onCreate 13.12 (Self Review) (True/False) The Context class provides methods for accessing the file system.

ANS: True.

13.13 Context method returns a File representing an application-specific external storage directory on the device—typically an SD card, but it could be on the device itself if it does not support SD cards.

ANS: getExternalFilesDir.

13.4.2 SlideshowEditor Class Event Listeners for the takePictureButton and addVideoButton 13.14 A MIME type of " device.

ANS: video/*.

" enables the user to select from the videos stored on the

13.4.3 PictureTaker Subclass of Activity Handling the SurfaceHolder’s Callbacks 13.15 (Self Review) (True/False) When the SurfaceView is created, changed or destroyed, its SurfaceHolder’s Callback methods are called.

ANS: True.

13.16 (Exercise) (True/False) Camera’s static open method can get a Camera object that allows the app to use the device’s rear facing camera.

ANS: True.

13.17 Use the Camera’s object to get the List<String> representing the camera’s supported effects and the List<Camera.Size> representing the supported preview image sizes.

Chapter 13—Enhanced Slideshow App: Test Item File Instructor Note

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ANS: Parameters.

13.18 (Exercise) The SurfaceHolder.Callback interface’s method is called each time the size or format of the SurfaceView changes—typically when the device is rotated and when the SurfaceView is first created and displayed.

ANS: surfaceChanged.

13.5 Wrap-Up 13.19 (Self Review) To use an object with the serialization mechanism, implement the interface Serializable.

ANS: tagging.

13.20 (Exercise) putStream’s

Read and method.

ANS: readObject.

13.21 (Self Review) A

deserialize

objects

with

an

ObjectIn-

can determine when a video finishes playing.

ANS: MediaPlayer.OnCompletionListener.

Chapter 14—Weather Viewer App: Test Item File Instructor Note

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Chapter 14—Weather Viewer App: Test Item File Instructor Note There are three categories of questions in this Test-Item File. The questions marked “(Self Review)” are provided with answers in the chapter’s Self-Review Exercises section. The questions marked “(Exercise)” are provided without answers in the chapter’s Exercises section. The remaining unmarked questions are provided only in this Test-Item File—the vast majority of these are questions that the students have not seen. We’ve included the self-review and exercise short-answer questions here so that you can use them to make up quizzes and exams, if you so choose.

14.1 Introduction 14.1

(Self Review) A ListFragment is a Fragment containing a ANS: ListView.

.

14.3 Technologies Overview Android 3.x Fragment, ListFragment and DialogFragment 14.2

(Exercise) (True/False) Fragments are a key feature of Android 3.x.

ANS: True.

14.3 A typically represents a reusable portion of an Activity’s user interface, but it can also represent reusable logic code.

ANS: fragment.

14.4

(True/False) The base class of all fragments is BaseFragment (package android.app).

ANS: False. The base class of all fragments is Fragment (package android.app).

14.5 (Self Review) (True/False) Fragments were introduced in Android 3.x and cannot be used with earlier versions of Android.

ANS: False. Though fragments were introduced in Android 3.x, there’s a compatibility package that enables you to use them with earlier versions of Android.

Managing Fragments 14.6

(Exercise) (True/False) Like an Activity, each Fragment has a life cycle.

ANS: True.

14.7

(Exercise) (True/False) Fragments can be executed independently of a parent Activity.

ANS: False. Fragments must be hosted in a parent Activity—they cannot be executed independently.

14.8 the

(Self Review) A FragmentTransaction (package android.app) obtained from allows the Activity to add, remove and transition between Fragments.

2

Chapter 14 ANS: FragmentManager.

Fragment Layouts 14.9 (True/False) Like an Activity, each Fragment has its own layout that’s typically defined as an XML layout resource, but also can be dynamically created.

ANS: True.

14.10 (Exercise) We use the Activity’s determine the current orientation.

ANS: Configuration.

(package android.content.res) to

Android 3.x Action Bar 14.11 (Self Review) (True/False) The action bar can display the app’s options menu, navigation elements (such as tabbed navigation) and other interactive GUI components.

ANS: True.

14.12 (True/False) You can designate menu items as actions that should be placed in the action bar if there’s room.

ANS: True.

Handling Long Touches 14.13 When the user long touches an item a ListFragment, an (package android.widget) to respond to that event.

ANS: AdapterView.OnItemLongClickListener.

you can use

Companion App Widget 14.14 (Self Review) We extend class AppWidgetProvider (package android.appwidget), a subclass of (package android.content), to create an app widget and allow it to receive notifications from the system when the app widget is enabled, disabled, deleted or updated.

ANS: BroadcastReceiver

PendingIntent to Launch an Activity from an App Widget

14.15 (Exercise) (True/False) It’s common practice to allow a user to launch an app by touching the app’s companion widget on the device’s home screen.

ANS: True.

Web Services and JsonReader 14.16 (Exercise) Use a ANS: JsonReader.

(package android.util) to read JSON objects.

Chapter 14—Weather Viewer App: Test Item File Instructor Note

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14.4 Building the App’s GUI and Resource Files 14.4.1 AndroidManifest.xml 14.17 Setting the uses-sdk element’s 3.1 SDK.

attribute to "12", indicates the Android

ANS: android-:minSdkVersion.

14.18 (Self Review) (True/False) Unlike activities, services need not be registered in the manifest.

ANS: False. Like activities, all services must be registered in the manifest; otherwise, they cannot be executed.

14.4.2 WeatherViewerActivity’s actionmenu.xml Menu Layout 14.19 (Exercise) The attribute android:showAsAction defines how a menu item should appear in the ActionBar. The value specifies that this item should be visible in the ActionBar if there’s room to lay it out completely.

ANS: ifRoom.

14.20 (Self Review) You can force an item to appear in the ActionBar by using the always value of attribute but you risk overlapping menu items by doing so.

ANS: android:showAsAction.

14.5 Building the App 14.5.1 Class WeatherViewerActivity WeatherViewerActivity Method selectForecast

14.21 (True/False) Pass FragmentTransaction’s TRANSIT_FRAGMENT_FADE constant to its setTransition method to visually fade the old Fragment into the new one.

ANS: True.

WeatherViewerActivity Method setupTabs

14.22 Pass ActionBar’s cate that you’ll be using Tabs.

constant to its setNavigationMode method to indi-

ANS: NAVIGATION_MODE_TABS.

14.5.2 Class ReadLocationTask ReadLocationTask Method doInBackground

14.23 (Self Review) (True/False) JSON (JavaScript Object Notation)—a simple way to represent JavaScript objects as numbers—is an alternative to XML for passing data between the client and the server.

4

Chapter 14 ANS: False. JSON (JavaScript Object Notation)—a simple way to represent JavaS-

cript objects as strings—is an alternative to XML for passing data between the client and the server.

14.24 (Exercise) (True/False) Each object in JSON is represented as a list of property names and values contained in curly braces, in the following format: { "propertyName1" : value1, "propertyName2'": value2 }

14.24 ANS: True.

14.25 (Self Review) (True/False) Arrays are represented in JSON with curly braces in the following format: { value1, value2, value3 }

14.25 ANS: False. Arrays are represented in JSON with square brackets.

14.26 (Exercise) (True/False) Each value in a JSON array can be a string, a number, a JSON representation of an object, true, false or null.

ANS: True.

14.27 (True/False) JsonReader has methods startObject and startArray to begin reading objects and arrays, respectively.

ANS: False. JsonReader has methods beginObject and beginArray to begin reading objects and arrays, respectively.

14.28 (Exercise) We get the name from the first name–value pair in the object with JsonReader’s method.

ANS: nextName.

14.29 (Self Review) (True/False) Class JsonReader provides methods for reading booleans, doubles, ints, longs and Strings.

ANS: True.

14.5.3 Class WeatherProvider WeatherProvider package Statement, import Statements and Constant

14.30 You can use the BITMAP_SAMPLE_SIZE constant to downsample the Bitmap to a size that can be used with —a View hierarchy that can be displayed in another process.

Android restricts the amount of data that can be passed between processes.

ANS: RemoteViews.

WeatherService Nested Class onForecastLoaded Method

14.31 A

represents an Intent and an action to perform with that Intent.

ANS: PendingIntent.

14.32 (Self Review) (True/False) A PendingIntent cannot be passed across processes.

ANS: False. A PendingIntent can be passed across processes.

Chapter 14—Weather Viewer App: Test Item File Instructor Note

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14.33 (Exercise) (True/False) When updating an app widget from an AppWidgetProvider, you update the app widget’s Views directly.

ANS: False. When updating an app widget from an AppWidgetProvider, you do not update the app widget’s Views directly.

WeatherService’s WeatherServiceLocationLoadedListener Class

14.6 Wrap-Up 14.34 (True/False) Each Fragment has a life cycle and it must be hosted in a parent Activity.

ANS: True.

14.35 (Exercise) You use a FragmentManager to manage the Fragments and a to add, remove and transition between Fragments.

ANS: FragmentTransaction.

14.36 (Self Review) (True/False) Use Fragments to create reusable components and make better use of the screen real estate in a tablet app.

ANS: True.