Multi Touch Listener

OnMultiTouchListener.java

 
/**
 * Multi touch event listener
 * 
 * @author viyu
 * 
 */
public abstract class OnMultiTouchListener implements OnTouchListener {
	/**
	 * last touch time
	 */
	private long lastTouchTime = 0;
	/**
	 * touched count
	 */
	private AtomicInteger touchCount = new AtomicInteger(0);

	private Runnable mRun = null;
	
	private Handler mHandler = new Handler();

	public void removeCallback() {
		mHandler.removeCallbacks(mRun);
	}

	@Override
	public boolean onTouch(final View v, final MotionEvent event) {
		if (event.getAction() == MotionEvent.ACTION_DOWN) {
			final long now = System.currentTimeMillis();
			lastTouchTime = now;

			touchCount.incrementAndGet();

			if (mRun != null) {
				mHandler.removeCallbacks(mRun);
			}

			mRun = new Runnable() {
				@Override
				public void run() {
					if (now == lastTouchTime) {
						onMultiTouch(v, event, touchCount.get());
						touchCount.set(0);
					}
				}
			};

			mHandler.postDelayed(mRun, getMultiTouchInterval());
		}
		return true;
	}

	/**
	 * max interval, default is 400, it can be overrided by subclass
	 * 
	 * @return
	 */
	protected int getMultiTouchInterval() {
		return 400;
	}

	/**
	 * multi touch callback
	 * 
	 * @param v
	 * @param event
	 * @param touchCount
	 *            touch count
	 * @return
	 */
	public abstract void onMultiTouch(View v, MotionEvent event, int touchCount);
}