android - 未检测到滑动

Question

在下面发布的代码中，我尝试使用 onDown 和 onFling 检测滑动，但是当我运行应用程序时，没有任何显示。

当我按住屏幕并快速将手指拖过屏幕时，我希望看到来自 onFling 的输出，但我什么也没收到。此外，我希望在按下屏幕时看到来自 onDown 的输出，但也没有显示任何内容。

请告诉我我遗漏了什么或者我误解了 onDown 上 onFling 的功能？!

Java代码:

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

首先，我假设您在 layout.xml 文件中的所有 View 都包含在 framelayout 中。并且您希望在整个 framelayout 中都能检测到您的滑动.如果是这样，请注册您的 framelayout到 GestureDetector 类型的对象如下代码所示:

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 ，这里是如何实现 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;
    }       
}