Question

在下面发布的代码中，我尝试使用onDown和onFling检测滑动但是当我运行应用时，什么都没有出现。

当我按住触摸屏幕并快速将手指拖过它时，我预计会看到来自onFling的输出，但我什么也没收到。另外，当我按下屏幕时，我希望看到输出来自onDown，但同样没有任何显示。

请让我知道我遗失的内容或者我在onFling上误解了onDown的功能？！

JavaCode：

super.onCreate(savedInstanceState);
    setContentView(R.layout.swipe_gesture_activivty);

    mGestureDetector = new GestureDetector(getApplicationContext(), new MySwipeGestureDetector());

            mViewGestureDetector = new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            // TODO Auto-generated method stub
            return mGestureDetector.onTouchEvent(event);
        }
    };
    final TextView view = (TextView) findViewById(R.id.accXLabel);      
}

private class MySwipeGestureDetector extends SimpleOnGestureListener implements OnTouchListener {

    @Override
    public boolean onDown(MotionEvent e) {
        // TODO Auto-generated method stub
        Toast.makeText(getApplicationContext(), "onDown", Toast.LENGTH_LONG).show();
        return true;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
            float velocityY) {
        // TODO Auto-generated method stub
        try {
            if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
                return false;
            // right to left swipe
            if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                Toast.makeText(getApplicationContext(), "Left Swipe", Toast.LENGTH_SHORT).show();
            }  else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                Toast.makeText(getApplicationContext(), "Right Swipe", Toast.LENGTH_SHORT).show();
            }
        } catch (Exception e) {
            // nothing
        }
        return false;

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        // TODO Auto-generated method stub
        return mGestureDetector.onTouchEvent(event);
    }

}

}

Answer 1

GestureDetector通过将多个MotionEvent转换为特定手势来工作。为此，它必须从视图的触摸事件中接收输入。

你只是缺少

view.setOnTouchListener(mViewGestureDetector);

用于特定视图（您想要捕捉到的视图）。

Answer 2

首先，我假设一个例子，layout.xml文件中的所有视图都包含在framelayout内，并且您希望在整个framelayout中可以检测到滑动。如果是，请将framelayout注册到GestureDetector类型的对象，如下面的代码所示：

FrameLayout mFL = (FrameLayout) findViewById(R.id.framelayoutID);

    mGestureDetector = new GestureDetector(getApplicationContext(), new MySwipeGestureDetector());
    mFL.setOnTouchListener(new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            // TODO Auto-generated method stub
            return mGestureDetector.onTouchEvent(event);
        }
    });

关于simpleOnGestureListener，以下是如何实施onFling。它对我有用。：

//define these variables globally:
/* private static final int MIN_DIST = 100;
private static final int MAX_OFF_PATH = 200;
private static final int THRESHOLD_VELOC = 200;*/
...
...
...
@Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
            float velocityY) {
        // TODO Auto-generated method stub
        try {
            if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
                return false;
            // right to left swipe
            if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                Log.i("SwipeGesture", "Left Swipe");
            }  else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                Log.i("SwipeGesture", "Right Swipe");
            }
        } catch (Exception e) {
            // nothing
        }
        return false;
    }       
}

滑动没有被检测到

2 个答案: