如何查找用戶是否從Android屏幕的底部邊緣開始滑動？

Question

我需要顯示一個自定義的視圖，如果用戶從屏幕的底部邊緣向上滑動。我已經實現SimpleOnGestureListener來查找滑動方向，但我堅持如何找到用戶是否從底部邊緣開始滑動？代碼是：

public class SimpleGestureFilter extends SimpleOnGestureListener{ 

    public final static String TAG = "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 = 50; //100 
    private int swipe_Max_Distance = 1350; //350 
    private int swipe_Min_Velocity = 50; //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()); 
     //e1. 
     Log.i(TAG, "X: "+ Math.abs(e1.getX())); 
     Log.i(TAG, "X1: "+ e2.getX()); 
     Log.i(TAG, "Y: "+ e1.getY()); 
     Log.i(TAG, "Y1: "+ e1.getY()); 
     Log.i(TAG, "edge: "+ e1.getEdgeFlags()); 

     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 arg0) { 
     this.listener.onDoubleTap();; 
     return true; 
    } 

    @Override 
    public boolean onDoubleTapEvent(MotionEvent arg0) { 
     return true; 
    } 

    @Override 
    public boolean onSingleTapConfirmed(MotionEvent arg0) { 

     if(this.mode == MODE_DYNAMIC){  // we owe an ACTION_UP, so we fake an 
      arg0.setAction(ACTION_FAKE);  //action which will be converted to an ACTION_UP later. 
      this.context.dispatchTouchEvent(arg0); 
     } 

     return false; 
    } 

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

} 

Answer 1

您可以使用MotionEvent.getEdgeFlags()來確定用戶是否從邊緣滑過。

public void onTouchEvent(MotionEvent event){ 

    if (ev.getAction() == MotionEvent.ACTION_DOWN 
      && ev.getEdgeFlags() == MotionEvent.EDGE_BOTTOM) { 
     // do something 
    } 

}