android - 安卓滑动手势

Question

我已经按照这个例子来实现滑动手势，但是如果我在活动中的任何地方滑动，我就不会收到 toast 消息。当我仅在特定位置滑动时，它会显示吐司。我想使用滑动手势移动到上一个屏幕。

我正在模拟器上尝试这个例子。

以下是我的活动：

public class SwipeScreenExample extends Activity implements SimpleGestureListener{
            private SimpleGestureFilter detector;

        @Override
            public void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.swipe_screen);

                // Detect touched area 
                detector = new SimpleGestureFilter(this,this);
        }

    @Override
    public boolean dispatchTouchEvent(MotionEvent me){
        // Call onTouchEvent of SimpleGestureFilter class
         this.detector.onTouchEvent(me);
       return super.dispatchTouchEvent(me);
    }
    @Override
     public void onSwipe(int direction) {
      String str = "";

      switch (direction) {

      case SimpleGestureFilter.SWIPE_RIGHT : str = "Swipe Right";
                                               break;
      case SimpleGestureFilter.SWIPE_LEFT :  str = "Swipe Left";
                                                     break;
      case SimpleGestureFilter.SWIPE_DOWN :  str = "Swipe Down";
                                                     break;
      case SimpleGestureFilter.SWIPE_UP :    str = "Swipe Up";
                                                     break;

      }
       Toast.makeText(this, str, Toast.LENGTH_SHORT).show();
     }

     @Override
     public void onDoubleTap() {
        Toast.makeText(this, "Double Tap", Toast.LENGTH_SHORT).show();
     }

  }

---

下面是gusture类：

public class SimpleGestureFilter extends SimpleOnGestureListener{

         public final static int SWIPE_UP    = 1;
         public final static int SWIPE_DOWN  = 2;
         public final static int SWIPE_LEFT  = 3;
         public final static int SWIPE_RIGHT = 4;

         public final static int MODE_TRANSPARENT = 0;
         public final static int MODE_SOLID       = 1;
         public final static int MODE_DYNAMIC     = 2;

         private final static int ACTION_FAKE = -13; //just an unlikely number
         private int swipe_Min_Distance = 100;
         private int swipe_Max_Distance = 350;
         private int swipe_Min_Velocity = 100;

     private int mode             = MODE_DYNAMIC;
     private boolean running      = true;
     private boolean tapIndicator = false;

     private Activity context;
     private GestureDetector detector;
     private SimpleGestureListener listener;

     public SimpleGestureFilter(Activity context,SimpleGestureListener sgl) {

      this.context = context;
      this.detector = new GestureDetector(context, this);
      this.listener = sgl;
     }

     public void onTouchEvent(MotionEvent event){

       if(!this.running)
      return; 

       boolean result = this.detector.onTouchEvent(event);

       if(this.mode == MODE_SOLID)
        event.setAction(MotionEvent.ACTION_CANCEL);
       else if (this.mode == MODE_DYNAMIC) {

         if(event.getAction() == ACTION_FAKE)
           event.setAction(MotionEvent.ACTION_UP);
         else if (result)
           event.setAction(MotionEvent.ACTION_CANCEL);
         else if(this.tapIndicator){
          event.setAction(MotionEvent.ACTION_DOWN);
          this.tapIndicator = false;
         }

       }
       //else just do nothing, it's Transparent
     }

     public void setMode(int m){
      this.mode = m;
     }

     public int getMode(){
      return this.mode;
     }

     public void setEnabled(boolean status){
      this.running = status;
     }

     public void setSwipeMaxDistance(int distance){
      this.swipe_Max_Distance = distance;
     }

     public void setSwipeMinDistance(int distance){
      this.swipe_Min_Distance = distance;
     }

     public void setSwipeMinVelocity(int distance){
      this.swipe_Min_Velocity = distance;
     }

     public int getSwipeMaxDistance(){
      return this.swipe_Max_Distance;
     }

     public int getSwipeMinDistance(){
      return this.swipe_Min_Distance;
     }

     public int getSwipeMinVelocity(){
      return this.swipe_Min_Velocity;
     }

     @Override
         public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
           float velocityY) {

          final float xDistance = Math.abs(e1.getX() - e2.getX());
          final float yDistance = Math.abs(e1.getY() - e2.getY());

          if(xDistance > this.swipe_Max_Distance || yDistance > this.swipe_Max_Distance)
           return false;

          velocityX = Math.abs(velocityX);
          velocityY = Math.abs(velocityY);
                boolean result = false;

          if(velocityX > this.swipe_Min_Velocity && xDistance > this.swipe_Min_Distance){
           if(e1.getX() > e2.getX()) // right to left
            this.listener.onSwipe(SWIPE_LEFT);
           else
            this.listener.onSwipe(SWIPE_RIGHT);

           result = true;
          }
          else if(velocityY > this.swipe_Min_Velocity && yDistance > this.swipe_Min_Distance){
           if(e1.getY() > e2.getY()) // bottom to up
            this.listener.onSwipe(SWIPE_UP);
           else
            this.listener.onSwipe(SWIPE_DOWN);

           result = true;
          }

           return result;
         }

     @Override
     public boolean onSingleTapUp(MotionEvent e) {
      this.tapIndicator = true;
      return false;
     }

     @Override
     public boolean onDoubleTap(MotionEvent arg) {
      this.listener.onDoubleTap();;
      return true;
     }

     @Override
     public boolean onDoubleTapEvent(MotionEvent arg) {
      return true;
     }

     @Override
     public boolean onSingleTapConfirmed(MotionEvent arg) {

      if(this.mode == MODE_DYNAMIC){        // we owe an ACTION_UP, so we fake an
         arg.setAction(ACTION_FAKE);      //action which will be converted to an ACTION_UP later.
         this.context.dispatchTouchEvent(arg);
      }  

      return false;
     }

        static interface SimpleGestureListener{
         void onSwipe(int direction);
         void onDoubleTap();
     }

    }

我没有对上述代码进行任何更改。只是我从上面提到的链接中复制了相同的内容。