Self-Review Exercises

7.1 Fill in the blanks in each of the following statements:

a) 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.

b) A Path object (package android.graphics) represents a geometric path consisting of line segments and _________.

c) You use the type of the touch event to determine whether the user has touched the screen, ________ or lifted a finger from the screen.

d) Use class SensorManager’s _________ method to stop listening for accelerometer events.

e) Override SensorEventListener method _________ to process accelerometer events.

f) Override Fragment method _________ to respond to the event when a Fragment is attached to a parent Activity.

g) When a View needs to be redrawn, its ________ method is called.

h) MotionEvent’s _________ method returns an int representing the MotionEvent type, which you can use with constants from class MotionEvent to determine how to handle each event.

i) Android 4.4’s _________ enables an app to take advantage of the entire screen.

7.2 State whether each of the following is true or false. If false, explain why.

a) You unregister the accelerometer event handler when the app is sent to the foreground.

b) Call the inherited View method validate to indicate that the View needs to be redrawn.

c) If the action is MotionEvent.ACTION_DOWN or MotionEvent.ACTION_POINTER_DOWN, the user touched the screen with the same finger.

d) 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.

e) Method MediaStore.Images.Media.saveImage saves a Bitmap into the device’s Gallery.