Question 1

Class SoundPool's ________ method gives the resources associated with a SoundPool back to the system.
A) reset
B) release
C) reinitialize
D) restore

Accepted Answer

The release() method of SoundPool releases the resources associated with it back to the system. This is important to prevent memory leaks and to efficiently manage system resources. The reset() method is used to reset the SoundPool object, reinitialize() is not a valid method for SoundPool, and restore() is not a valid method for releasing resources in SoundPool.

Question 2

Methods getScreenWidth and getScreenHeight return the width and height of the screen, which are updated in the ________ method.
A) onOrientationChanged
B) onSizeChanged
C) onConfigurationChanged
D) None of the above

Accepted Answer

The answer of Methods getScreenWidth and getScreenHeight return the width...

Question 3

Method surfaceCreated is called when the SurfaceView is created-e.g., ________.
A) when the app first loads
B) when the app resumes from the background
C) Both of the above
D) Neither of the above

Accepted Answer

The method surfaceCreated is called in both scenarios: when the app first loads and when it resumes from the background, as part of the lifecycle of a SurfaceView in Android.

Question 4

View method onTouchEvent determines when the user touches the screen. The MotionEvent parameter contains information about the event that occurred. If the user touched the screen, the parameter’s value is ________. 
A) MotionEvent.ACTION_DOWN
B) MotionEvent.ACTION_TOUCH
C) MotionEvent.ACTION_TAP
D) MotionEvent.ACTION_DRAG

Accepted Answer

According to the description, the method onTouchEvent determines when the user touches the screen and the parameter's value would be MotionEvent.ACTION_DOWN if the user has touched the screen, making option A the correct choice. The other options, B, C, and D, do not accurately represent the value of the parameter in this scenario.

Question 5

Method ________ of interface SurfaceHolder.Callback is called when the SurfaceView's size or orientation changes, and would typically be used to redisplay graphics based on those changes.
A) surfaceSizeChanged
B) surfaceOrientationChanged
C) onSizeChanged
D) surfaceChanged

Accepted Answer

The correct method is `surfaceChanged` from the `SurfaceHolder.Callback` interface. This method is called immediately after any structural changes (format or size) have been made to the surface. This allows you to manage the redrawing and resizing of your graphics in response to size or orientation changes of the `SurfaceView`.

Question 6

You can call Canvas's drawRect method to clear the Canvas. The method receives the rectangle's upper-left x-y coordinates, width and height, and the ________ object that specifies the drawing characteristics.
A) Draw
B) PaintSettings
C) Paint
D) DrawSettings

Accepted Answer

The drawRect method requires a Paint object that specifies the drawing characteristics, such as color and stroke style. Therefore, the best choice would be C) Paint.

Question 7

A dialog must be displayed from the GUI thread. You call Activity method ________ to specify a Runnable that should execute in the GUI thread.
A) runOnUiThread
B) executeOnUIThread
C) uiThread
D) None of the above

Accepted Answer

The correct method to call to specify a Runnable that should execute in the GUI thread is runOnUiThread. This method is specific to the Activity class and ensures that the Runnable is executed on the main UI thread. This is important because UI elements can only be updated from the main thread. Option B (executeOnUIThread) is not a valid method for the Activity class and options C and D are incorrect.

Question 8

Only one thread at a time can draw to a SurfaceView. To ensure this, you must first lock the SurfaceHolder by ________. 
A) calling lockSurfaceHolder  
B) specifying it as the expression in the parentheses of a synchronized block.
C) calling getSurfaceHolderLock
D) None of the above

Accepted Answer

The correct way to lock the SurfaceHolder is by specifying it as the expression inside a synchronized block. This ensures that only one thread at a time can access and draw on the SurfaceView. The other options, such as calling lockSurfaceHolder or getSurfaceHolderLock, are not valid methods and do not exist.

Question 9

You can terminate a Thread by calling its setRunning method with the argument ________.
A) terminate
B) true
C) kill
D) false

Accepted Answer

The setRunning method takes a boolean argument to indicate whether the thread should continue running or not. Passing false as the argument will terminate the thread by setting the running flag to false.

Question 10

To obtain the Canvas for drawing on the SurfaceView, call SurfaceHolder method ________.
A) getCanvas
B) createCanvas
C) newCanvas
D) lockCanvas

Accepted Answer

To obtain the Canvas for drawing on the SurfaceView, we need to call the lockCanvas method of the SurfaceHolder. This method returns a Canvas object that we can use for drawing on the SurfaceView. The other choices (A, B, and C) are not valid methods for obtaining a Canvas object on a SurfaceView.

Quiz 6: Cannon Game App

Class SoundPool's ________ method gives the resources associated with a SoundPool back to the system.

Methods getScreenWidth and getScreenHeight return the width and height of the screen, which are updated in the ________ method.

Method surfaceCreated is called when the SurfaceView is created-e.g., ________.

View method onTouchEvent determines when the user touches the screen. The MotionEvent parameter contains information about the event that occurred. If the user touched the screen, the parameter’s value is ________.

Method ________ of interface SurfaceHolder.Callback is called when the SurfaceView's size or orientation changes, and would typically be used to redisplay graphics based on those changes.

You can call Canvas's drawRect method to clear the Canvas. The method receives the rectangle's upper-left x-y coordinates, width and height, and the ________ object that specifies the drawing characteristics.

A dialog must be displayed from the GUI thread. You call Activity method ________ to specify a Runnable that should execute in the GUI thread.

Only one thread at a time can draw to a SurfaceView. To ensure this, you must first lock the SurfaceHolder by ________.

You can terminate a Thread by calling its setRunning method with the argument ________.

To obtain the Canvas for drawing on the SurfaceView, call SurfaceHolder method ________.