即使在單點觸控交互中也會發生多點觸控變焦

Question

我編寫了用於放大/縮小的代碼。它可以工作，但即使用一個手指放大/縮小，它應該只能用2個手指（多點觸控）工作。任何知道爲什麼？

boolean surfaceTouchEvent(MotionEvent event) { 
     pointNum=event.getPointerCount(); 
     switch (event.getAction() & MotionEvent.ACTION_MASK) { 
     case MotionEvent.ACTION_DOWN: 
     //User is pressing on finger 
     x0=event.getX(0); 
     y0=event.getY(0); 
     mode = false; //DRAG 
     break; 
     case MotionEvent.ACTION_POINTER_DOWN: 
     x1=event.getX(0); 
     x2=event.getX(1); 
     y1=event.getY(0); 
     y2=event.getY(1); 
     z4 = dist(x1, y1, x2, y2); 
     mode = true; // pinch 
     break; 
    case MotionEvent.ACTION_UP: 
    mode = false; 
     case MotionEvent.ACTION_POINTER_UP: 
     // User is released one of the fingers. 
     mode = false; 

     break; 
     case MotionEvent.ACTION_MOVE: 
     if (mode = false) { 
     // x1=event.getX(0)-x0; 
      //y1=event.getY(0)-y0; 
     } 
     if (mode = true) { 
      x1=event.getX(0); 
      x2=event.getX(1); 
      y1=event.getY(0); 
      y2=event.getY(1); 
      float z3 = dist(x1, y1, x2, y2); 
      if (z3 > z4) { 
      zoom += 0.1; 
      } 
      else if (z3 < z4) { 
      zoom -= 0.1; 
      } 
     } 
     break; 
     } 
     return super.surfaceTouchEvent(event); 
    } 

我編輯如下代碼，但這次是不工作的，至少第一代碼的作品，但變焦反應奇怪，請大家幫忙

float x1,x2,y1,y2 = -1; 
    boolean surfaceTouchEvent(MotionEvent event) { 
     pointNum=event.getPointerCount(); 
     if (pointNum >=2) { 
     x1=event.getX(0); 
     x2=event.getX(1); 
     y1=event.getY(0); 
     y2=event.getY(1); 
     z4 = dist(x1, y1, x2, y2); 
     if (z3 > z4) { 
      zoom += z3/z4; 
     } 
     else if (z3 < z4) { 
      zoom -= z3/z4; 
     } 
     } 
     else { 
     return false; 
     } 
     z3 = z4; 
     return super.surfaceTouchEvent(event); 
    } 

Answer 1

你應該只有在執行該有不止一個手指。 只需將您的代碼之前，如果添加此：

boolean surfaceTouchEvent(MotionEvent event) { 
    pointNum=event.getPointerCount(); 
    if(pointNum >= 2) { 
    // your code here 
    } else { 
    return false; 
    } 
}