Android™ Application Development - Bahar Ali Khan

Chapter 11: Advanced Android Development
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}
}
}
for (int i = 0; i < historySize; i++) {
float x = event.getHistoricalX(i);
float y = event.getHistoricalY(i);
processMovement(x, y);
}
float x = event.getX();
float y = event.getY();
processMovement(x, y);
return true;
return super.onTouchEvent(event);
private void processMovement(float _x, float _y) {
// Todo: Do something on movement.
}
Android includes two excellent examples of using the touch screen in the Fingerpaint and
Touch Paint API Demos.
Using the OnTouchListener
You can listen for touch events without subclassing an existing View by attaching an OnTouchListener
to any View object, using the setOnTouchListener method. The following code snippet demonstrates
how to assign a new OnTouchListener implementation to an existing View within an Activity:
myView.setOnTouchListener(new OnTouchListener() {
});
public boolean onTouch(View _view, MotionEvent _event) {
// TODO Respond to motion events
return false;
}
Using the Device Keys and Buttons (Including D-Pad)
Button and key-press events for all hardware keys are handled by the onKeyDown and onKeyUp handlers
of the active Activity or the focused view. This includes keyboard keys, D-pad, volume, back, dial,
and hang-up buttons. The only exception is the Home key, which is reserved to ensure that users can
never get locked within an application.
To have your View or Activity react to button presses, override the onKeyUp and onKeyDown event handlers
as shown in the following skeleton code:
@Override
public boolean onKeyDown(int _keyCode, KeyEvent _event) {
// Perform on key pressed handling, return true if handled