Deck 3: Tip Calculator App

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.

Answer 1

C

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.

Answer 2

D

Question 3

Activities transition between their states in response to various .

A) actions
B) steps
C) events
D) deeds

Answer 3

C

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

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%

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.

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

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

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.

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.

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

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

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.

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.

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

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.

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

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

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

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

Question 21

By default, a SeekBar’s range is 0 to 100 and its current value is indicated by its property.

A) progress
B) value
C) thumb
D) None of the above.

Question 22

When the virtual keyboard is displayed, the device's back button changes to a down button that enables you to .

A) scroll down the screen
B) dismiss the app's current activity and return to the prior one.
C) hide the app
D) dismiss the keyboard

Question 23

Each app has a theme that defines the default look-and-feel of the standard views you use. The theme is specified in the app’s AndroidManifest.xml file. You can customize aspects of an app’s theme, such those that define an app’s color scheme, by defining style resources in the file located in the app’s res/values folder.

A) themes.xml
B) styles.xml
C) colors.xml
D) None of the above.

Question 24

Which of the following actions does not change the device's configuration?

A) rotating the device
B) connecting to a Bluetooth keyboard
C) sliding out a hard keyboard
D) All of the above change the device's configuration.

Question 25

Which of the following satements is false?

A) The style.xml resource file contains a style with the name "AppTheme" that's referenced from the app's AndroidManifest.xml file to specify the app's theme.
B) A parent theme is similar to a subclass in Java-the new style inherits its parent theme's attributes and their default values.
C) Just as in a Java subclass, a style can override parent theme attributes with values customized for specific apps.
D) By default, Android Studio sets the parent theme to Theme.AppCompat.Light.DarkActionBar
One of several predefined themes from the AppCompat library-apps that use this theme have a light background, except for the dark app bar at the top of the app.

Question 26

The default layout for an Empty Activity is a .

A) GridLayout
B) LinearLayout
C) RelativeLayout
D) None of the above.

Question 27

Why would you set the digits property of an EditText to 0123456789?

A) To allow only characters other than the digits 0-9 to be entered.
B) To allow only the string of digits 0123456789 to be entered.
C) To allow only digits to be entered (in any order and combination).
D) None of the above.

Question 28

Which of the following statements about class R's nested classes is false?

A) class R.drawable contains constants for any drawable items, such as images, that you put in the various drawable folders in your app's res folder.
B) class R.id contains constants for the views in your HTML layout files.
C) class R.layout contains constants that represent each layout file in your project (such as, activity_main.xml).
D) class R.string contains constants for each String in the strings.xml file.

Question 29

Which of the next three statements is false?

A) By default, there are no margins-spacing that separates views-around a GridLayout's cells.
B) The material design guidelines recommend 18dp minimum spacing between views.
C) GridLayout can enforce the recommended spacing between views. With the GridLayout selected in the Component Tree, in the Properties window, check the GridLayout's useDefaultMargins property (which sets it to true) to use the recommended margins around the layout's cells.
D) All of the above statements are true.

Question 30

The call to setContentView receives the R.layout constant indicating the XML file that represents a GUI-e.g., R.layout.activit_main represents the activity_main.xml file. Method setContentView uses this constant to load the corresponding XML document, which Android parses and converts into the app's GUI. This process is known as the GUI.

A) creating
B) inflating
C) fabricating
D) building

Question 31

Which of the next three statements is false?

A) style resources can define common property values that should be applied to multiple views.
B) You apply a style resource to a given view by setting its style property.
C) Any subsequent changes you make to a style are automatically applied to all views using the style.
D) All of the above statements are true.

Question 32

Method onCreate typically initializes the Activity's instance variables and views. This method should be as simple as possible so that the app loads quickly. If the app takes longer than five seconds to load, the operating system will display a(n) dialog, giving the user the option to forcibly terminate the app.

A) PNR (Program Not Responding)
B) ANR (Application Not Responding)
C) ANR (Android Not Responding)
D) None of the above.

Question 33

Which of the following statements is false?

A) Class Bundle of package android.os stores key–value pairs of infor-mation—typically representing an app’s state or data that needs to be passed between activities.
B) When another app is about to appear on the screen—e.g., when the user re-ceives a phone call or launches another app—Android gives the currently exe-cuting app the opportunity to save its state in a Bundle. The Android runtime might subsequently kill the app—e.g., to reclaim its memory.
C) When the app returns to the screen, the Android runtime passes the Bundle of the previously saved state to Activity method onStart.
D) We can use Bundles to pass data between activities.

Question 34

Method is called whenever the SeekBar's thumb position changes.

A) onProgressChanged
B) onSeekBarChanged
C) onThumbPositionChanged
D) onValueChanged

Question 35

For precise monetary calculations, use class (package java.math)-rather than type double-to represent the monetary amounts and perform calculations.

A) MonetaryAmount
B) Cash
C) BigDecimal
D) None of the above.

Question 36

Which of the following statements is false?

A) App-Activity is an indirect subclass of Activity that supports using newer Android features apps running on current and older Android platforms.
B) You implement interface TextWatcher of package android.text to respond to events when the user changes the text in an EditText.
C) You implement interface SeekBar.OnSeekBarChangeListener of package android.widget to respond to the user moving the SeekBar’s thumb.
D) Class NumberFormat of package java.text provides numeric formatting ca-pabilities, such as locale-specific currency and percentage formats.

Question 37

Class Activity's method takes an int constant representing a specific view's ID and returns a reference to the view.

A) findId
B) findView
C) findViewById
D) None of the above.

Question 38

Which of the following statements is false?

A) A GridLayout (package android.widget) arranges views into rows and columns, each indexed from 0 like the elements of an array.
B) Each cell of a GridLayout can be empty or can hold one or more views, in-cluding layouts containing other views.
C) A GridLayout row’s height is determined by the row’s tallest view--similarly, a column’s width is defined by the column’s widest view.
D) A GridLayout’s views can span multiple rows and/or columns.

Question 39

You can use the new Android Studio to change the app's primary, dark primary and accent colors.

A) Color Editor
B) Design Editor
C) Layout Editor
D) Theme Editor

Question 40

Java requires that you override every method in an that you implement.

A) struct
B) class
C) interface
D) enumeration

Question 41

For apps you submit to the Google Play store, the is used as the app's unique identifier.

A) app name
B) class name
C) package name
D) folder name

Question 42

Which of the following statements about Intents is false?

A) Intents are Android's mechanism for communicating between executable components-such as activities, background services and the operating system.
B) You state your intent, then Android uses intent messaging to coordinate the executable components to accomplish what you intend to do.
C) This tight coupling makes it easy to mix and match parts of different applications.
D) You tell Android what you want to accomplish, then let Android find the installed applications with activities that can handle the task.

Question 43

Which of the following statements is false?

A) If an Intent matches only one Activity's intent-filter, Android executes that Activity.
B) If there are multiple matches, Android presents a list from which the user can choose an app, then executes the appropriate Activity in that app.
C) An Intent often contains data the Activity can use to perform its task.
D) The intent-filter element optionally can contain one or more action elements.

Question 44

The manifest element’s nested element specifies attributes of the application.

A) activity
B) application
C) app
D) None of the above.

Question 45

Which of the following is false regarding the manifest's activity element?

A) android:name is the app's name.
B) android:label is the Activity's name.
C) android:screenOrientation specifies the Activity's orientation.
D) android:windowSoftInputMode can be used to specify that the soft keypad should be displayed immediately when the app executes and should reappear each time the user returns to the app.

Question 46

The method is called whenever the text in the amount-EditText is modified.

A) onNewValue
B) onEditTextChanged
C) watchedTextChanged
D) onTextChanged

Question 47

In the manifest, the activity element’s nested element determines which Intent types can launch an Activity-.

A) intent
B) filter
C) intent--filter
D) filter-intents