手势处理帮助类

GestureDetector

通过MotionEvents检测各种手势和事件，并通过GestureDetector.OnGestureListener回调处理。

To use this class:

• Create an instance of the GestureDetector for your View
• In the onTouchEvent(MotionEvent) method ensure you call onTouchEvent(MotionEvent). The methods defined in your callback will be executed when the events occur.
• If listening for onContextClick(MotionEvent) you must call onGenericMotionEvent(MotionEvent) in onGenericMotionEvent(MotionEvent).

code:

public class DetectingGesturesActivity extends Activity implements GestureDetector.OnGestureListener{
    private static final String DEBUG_TAG = "Gestures";
    private GestureDetector mDetector;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_detecting_gestures);

        mDetector = new GestureDetector(this, this);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event){
        this.mDetector.onTouchEvent(event);
        // Be sure to call the superclass implementation
        return super.onTouchEvent(event);
    }

    @Override
    public boolean onDown(MotionEvent event) {
        Log.d(DEBUG_TAG,"onDown: " + event.toString());
        return true;
    }

    @Override
    public boolean onFling(MotionEvent event1, MotionEvent event2,
                           float velocityX, float velocityY) {
        Log.d(DEBUG_TAG, "onFling: " + event1.toString()+event2.toString());
        return true;
    }

    @Override
    public void onLongPress(MotionEvent event) {
        Log.d(DEBUG_TAG, "onLongPress: " + event.toString());
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
                            float distanceY) {
        Log.d(DEBUG_TAG, "onScroll: " + e1.toString()+e2.toString());
        return true;
    }

    @Override
    public void onShowPress(MotionEvent event) {
        Log.d(DEBUG_TAG, "onShowPress: " + event.toString());
    }

    @Override
    public boolean onSingleTapUp(MotionEvent event) {
        Log.d(DEBUG_TAG, "onSingleTapUp: " + event.toString());
        return true;
    }
}