Question 1

You'll use an anonymous inner class to implement the__________interface (from package android.widget) to respond to the user moving the SeekBar's thumb.
A) SeekBar.OnSeekBarChangeListener
B) SeekBar.ChangeListener
C) SeekBar.OnChangeListener
D) None of the above.

Accepted Answer

The SeekBar class in android.widget package has an OnSeekBarChangeListener interface that provides methods to respond to the SeekBar's progress being changed by the user moving the thumb. In order to implement this interface and provide the desired behavior on user interaction with the SeekBar, an anonymous inner class can be used. Therefore, the correct choice is A) SeekBar.OnSeekBarChangeListener. The other options (B) SeekBar.ChangeListener and (C) SeekBar.OnChangeListener) are not valid interfaces in the android.widget package. Option D) None of the above does not provide a correct solution to the problem.

Question 2

Which of the following three statements is true?
A) You arrange a GUI's views in layouts.
B) A GridLayout (package android-.widget) arranges views into cells in a rectangular grid.
C) Cells in a GridLayout can occupy multiple rows and columns, allowing for complex layouts.
D) All of the above statements are true.

Accepted Answer

All of the statements are true. In Android, GUI views are arranged in layouts, and the GridLayout is a widget package that arranges views in a rectangular grid by dividing the layout into cells. These cells can occupy multiple rows and columns, which allows for complex layouts.

Question 3

Activities transition between their states in response to various_____________.
A) actions
B) steps
C) events
D) deeds

Accepted Answer

Activities transition between their states in response to various events, which could be triggered by internal or external factors.

Question 4

You’ll use class          (package java.text) to create locale-specific cur-rency and percentage strings—an important part of internationalizing your apps. 
A) LocaleFormat 
B) StringFormat 
C) InternationalFormat 
D) NumberFormat

Accepted Answer

The class needed to create locale-specific currency and percentage strings is NumberFormat, not LocaleFormat, StringFormat, or InternationalFormat. NumberFormat provides methods to format numbers, currencies, and percentages for a specific locale.

Question 5

Many of today's Android phones use AMOLED displays. On such displays, a black pixel is turned off and does not consume power. Apps that use mostly black themes can reduce power consumption by approximately_________.
A) 10%
B) 70%
C) 40%
D) 90%

Accepted Answer

AMOLED displays save power by turning off black pixels, and using mostly black themes can reduce power consumption by around 40% as the display consumes less energy.

Question 6

Which of the following statements is false?
A) A theme gives an app a look-and-feel that's consistent with Android.
B) Projects that you create for Android 5 and higher use themes that adhere to Google's material- design guidelines.
C) There are several predefined material design themes: The "light" theme has a white app bar, a white app background and text that is black or shades of dark gray.
D) When designing a GUI, you must choose from the predefined themes.

Accepted Answer

When designing a GUI, you can choose to use a predefined theme or create a custom theme that meets your design requirements. Therefore, statement D is false.

Question 7

Android apps have four types of executable components—activities, services, content providers and         . 
A) broadcast receivers
B) broadcast transmitters
C) broadcasters
D) receivers

Accepted Answer

The fourth type of executable component in Android apps is broadcast receivers, which are responsible for receiving and processing system-wide broadcast messages. Options B, C, and D are not correct as they are either not valid components or do not correctly describe the fourth component.

Question 8

A(n) ________is a subclass of Text-View that can display text and accept text input from the user. 
A) TextBox
B) EditText
C) TextField
D) EditInput

Accepted Answer

EditText is a subclass of TextView that enables the user to input and edit text. Option A and C are not available classes in Android development, and option D is not a valid class name.

Question 9

Google now introduces many new Android features via the Android Support Library—a set of libraries that enable you to         . 
A) use newer Android features in apps targeting current and past Android plat-forms
B) use new Android features only in the current Android platform version
C) use old Android features in new Android platforms
D) None of the above.

Accepted Answer

The Android Support Library enables developers to use newer Android features in apps targeting current and past Android platforms, ensuring wider compatibility and accessibility of new features for users.

Question 10

Android Studio's app templates have been updated to use the____________library, enabling the new apps you create to run on almost all Android devices, including ones with older Android versions.
A) Compatibility
B) AppCompat
C) SupportLibrary
D) None of the above.

Accepted Answer

The statement explicitly mentions the use of the AppCompat library in the updated templates, making Option B the correct choice. The other options mentioned - Compatibility and SupportLibrary - do exist, but they are not specifically referenced in the statement as being the ones used in the updated templates.

Question 11

You may configure your AVD (or device) to display the________________keyboard for better contrast in your screen captures.
A) black
B) shaded
C) dark
D) ebony

Accepted Answer

Choosing a dark keyboard on your AVD or device can provide better contrast in screen captures, making it easier to see the text and graphics.

Question 12

To respond to events when the user changes the text in an EditText, you’ll use an anonymous inner class to implement the          interface (from package android-.text).  
A) EditTextListener
B) TextListener 
C) EditTextWatcher
D) TextWatcher

Accepted Answer

The correct interface to respond to events when the user changes the text in an EditText is TextWatcher from package android.text. A and B are not valid interfaces in Android and C is a made up interface.

Question 13

Which of the following statements is false?
A) An app can have many activities, and an Activity can manage multiple Fragments. 
B) You interact with an Activity through views—GUI components that inherit from class View (package android.view). 
C) Before Android 3.0, a separate Activity was typically associated with each screen of an app. 
D) On a tablet, each Fragment typically occupies the entire screen and the Ac-tivity switches between the Fragments, based on user interactions.

Accepted Answer

On a tablet, Fragments can be displayed side-by-side or one on top of the other, allowing multiple Fragments to be displayed at the same time. Therefore, each Fragment does not typically occupy the entire screen on a tablet.

Question 14

Which of the following statements is false?
A) If you need to customize theme colors, Google’s material design guidelines for color recommend that you choose a color palette consisting of a primary color—with no more than five hues (shades)—and an accent color. 
B) The primary colors typically are used to color the status bar and the app bar at the top of the screen and also can be used in your GUI. 
C) The accent color is used to tint various views in your GUI, such as SeekBars, CheckBoxes and RadioButtons. 
D) Once you choose a palette, you can use Android Studio’s Theme Editor to modify a theme’s colors.

Accepted Answer

The false statement is A because Google's Material Design guidelines do not limit the primary color palette to no more than five hues. They provide a wide range of hues for primary and secondary colors but do not specify such a strict limit.

Question 15

A_____________represents an integer in the range 0-100 by default and allows the user to select a number in that range by moving its thumb.
A) GridLayout
B) EditText
C) SeekBar
D) None of the above

Accepted Answer

The SeekBar is designed to allow the user to select a number within a specific range by sliding a thumb along a horizontal bar. The default range for a SeekBar is 0-100, which makes it a good choice for representing integers in that range. The GridLayout is used to arrange views in a grid-like structure and does not have any built-in functionality for selecting numbers. The EditText is used for inputting text, not selecting integers within a specific range.

Question 16

Which of the following statements is false?
A) An active Activity is visible on the screen and "has the focus"-that is, it's in the foreground. You can interact with the Activity currently in the foreground.
B) A stopped activity is not visible on the screen-it's in the background and is likely to be killed by the system when its memory is needed.
C) An Activity is stopped when another Activity enters the foreground and becomes active. For example, when you answer a phone call, the phone app becomes active and the app you previously were using is stopped.
D) Each activity lifecycle method you override must call the subclass's version; otherwise, an exception will occur.

Accepted Answer

The statement "Each activity lifecycle method you override must call the subclass's version; otherwise, an exception will occur" is false. While it's recommended to call the superclass version of an overridden method, it's not required and there won't be an exception if you don't.

Question 17

By default, the Seekbar allows you to select values from 0 to 100.
A) 1 to 100
B) 1 to 256
C) 0 to 100
D) 0 to 256

Accepted Answer

By default, the Seekbar allows you to select values from 0 to 100.

Question 18

Throughout its life, an Activity can be in one of several states—active (i.e., running),          or stopped. 
A) halted
B) paused
C) ceased
D) discontinued

Accepted Answer

The activity can also be paused in addition to being active or stopped. "Halted," "ceased," and "discontinued" are not typically used to describe the state of an activity in Android development.

Question 19

When you set a view's___________property, Android automatically casts a shadow for that view.
A) shadow
B) elevation
C) altitude
D) levitation

Accepted Answer

When you set a view's elevation property, Android automatically casts a shadow for that view.

Question 20

A SeekBar listeners’s          method executes when the user moves the SeekBar’s thumb.
A) onThumbMoved 
B) userMovedThumb
C) onProgressChanged
D) None of the above

Accepted Answer

The onProgressChanged method executes when the user moves the SeekBar's thumb and the progress value is changed.

Quiz 3: Tip Calculator App

You'll use an anonymous inner class to implement the__________interface (from package android.widget) to respond to the user moving the SeekBar's thumb.

Which of the following three statements is true?

Activities transition between their states in response to various_____________.

You’ll use class (package java.text) to create locale-specific cur-rency and percentage strings—an important part of internationalizing your apps.

Many of today's Android phones use AMOLED displays. On such displays, a black pixel is turned off and does not consume power. Apps that use mostly black themes can reduce power consumption by approximately_________.

Which of the following statements is false?

Android apps have four types of executable components—activities, services, content providers and .

A(n) ________is a subclass of Text-View that can display text and accept text input from the user.

Google now introduces many new Android features via the Android Support Library—a set of libraries that enable you to .

Android Studio's app templates have been updated to use the____________library, enabling the new apps you create to run on almost all Android devices, including ones with older Android versions.

You may configure your AVD (or device) to display the________________keyboard for better contrast in your screen captures.

To respond to events when the user changes the text in an EditText, you’ll use an anonymous inner class to implement the interface (from package android-.text) .

Which of the following statements is false?

Which of the following statements is false?

A_____________represents an integer in the range 0-100 by default and allows the user to select a number in that range by moving its thumb.

Which of the following statements is false?

By default, the Seekbar allows you to select values from 0 to 100.

Throughout its life, an Activity can be in one of several states—active (i.e., running) , or stopped.

When you set a view's___________property, Android automatically casts a shadow for that view.

A SeekBar listeners’s method executes when the user moves the SeekBar’s thumb.