具有自定义基于视图的类的手势检测器

Posted 2023-02-26

【中文标题】具有自定义基于视图的类的手势检测器

【英文标题】：Gesture Detector with a Custom View-Based Class

【发布时间】：2011-12-20 21:34:36

【问题描述】：

我希望您能帮助我弄清楚为什么我的 CustomView 类中定义的 OnSwipe、OnDoubleTap 和 onSingTapConfirmed 方法是使用以下行从活动 onCreate 实例化的 -

CustomView customView = new CustomView(this);

没有被调用。 CustomView 扩展了一个 View 并实现了 MyGestureListener 接口。请参阅下面的代码。

public class CustomView extends View implements MyGestureListener 

private MyGestureDetector mGestureDetector;

public CustomView(Context context) 
        super(context);

    mGestureDetector = new MyGestureDetector(context, this);


@Override 
public boolean dispatchTouchEvent(MotionEvent me) 
    this.mGestureDetector.onTouchEvent(me);
    return super.dispatchTouchEvent(me); 


@Override
public void onSwipe(int direction) 
    String str = "";

    switch (direction) 

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

    Toast.makeText(getContext(), str, Toast.LENGTH_SHORT).show();
 

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

 @Override
 public void onSingleTapConfirmed() 
    Toast.makeText(getContext(), "Single Tap", Toast.LENGTH_SHORT).show(); 
 



public class MyGestureDetector extends GestureDetector.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;
 private int swipe_Min_Distance = 100;
 private int swipe_Max_Distance = 350;
 private int swipe_Min_Velocity = 100;

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

 private Context context;
 private GestureDetector detector;
 private MyGestureListener listener;

 public MyGestureDetector(Context context, MyGestureListener 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 arg0) 
  this.listener.onDoubleTap();
  return true;
 

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

 @Override
 public boolean onSingleTapConfirmed(MotionEvent arg0) ;
    this.listener.onSingleTapConfirmed();
    return true;
 

 static interface MyGestureListener
     void onSwipe(int direction);
     void onDoubleTap();
     void onSingleTapConfirmed();
 

【参考方案1】：

您应该在 down 操作中返回 true ...否则永远不会调用其他回调操作 ...如 android doc 中所述

注意创建一个为 ACTION_DOWN 事件返回 false 的侦听器。如果您这样做，则不会为后续的 ACTION_MOVE 和 ACTION_UP 事件字符串调用侦听器。这是因为 ACTION_DOWN 是所有触摸事件的起点。