android 简单的 左右上下手势 判断

private float startx;
	private float starty;
	private float upoffset;

	@Override
	public boolean onTouchEvent(MotionEvent event) {

		switch (event.getAction()) {
		case MotionEvent.ACTION_DOWN:
			startx = event.getX();
			starty = event.getY();
			break;
		case MotionEvent.ACTION_MOVE:
			offset = (int) (event.getX() - startx) / 3;
			// Log.e("TAST", offset + "offset");
			if (Math.abs(offset) > 10) {
				Log.e("TAG", "Left and Right");
			}
			upoffset = event.getY() - starty;
			if (Math.abs(upoffset) > 20) {
				Log.e("TAG", "UP and Down");
			}

			invalidate();

		default:
			break;
		}

		return true;
	}