UIScrollView touchesBegan

Question

所以我想做的就是当用户触摸UIScrollView时播放声音。UIScrollViewDelegate具有scrollViewWillBeginDragging:方法，但它只在touchMoved上被调用。我希望它在touchBegan上被调用。

尝试触摸doesn:withEvent:但它没有收到任何触摸。有谁有线索吗？

Answer 1

我认为你必须继承UIScrollView才能做到这一点。

touchesBegan:withEvent:仅发送到UIView的子类。你在你的控制器中实现touchesBegan:withEvent:是有问题的吗？如果是这样，它就不会在那里工作了.

或者，如果您将(您编写的) UIView的子类放在UIScrollView中，您还可以从那里捕获touchesBegan事件(但仅当用户触摸该特定的子视图时)。默认情况下，UIScrollView会将touches传递给它的子视图(参见touchesShouldBegin:withEvent: in inContentView:in UIScrollView)。

Answer 2

改用点击手势识别器：

UITapGestureRecognizer *recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(touch)];
[recognizer setNumberOfTapsRequired:1];
[recognizer setNumberOfTouchesRequired:1];
[scrollView addGestureRecognizer:recognizer];  

或

创建UIScrollView的subClass并实现所有

    -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{

// If not dragging, send event to next responder
  if (!self.dragging){ 
    [self.nextResponder touchesBegan: touches withEvent:event]; 
  }
  else{
    [super touchesEnded: touches withEvent: event];
  }
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

// If not dragging, send event to next responder
    if (!self.dragging){ 
     [self.nextResponder touchesBegan: touches withEvent:event]; 
   }
   else{
     [super touchesEnded: touches withEvent: event];
   }
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{

  // If not dragging, send event to next responder
   if (!self.dragging){ 
     [self.nextResponder touchesBegan: touches withEvent:event]; 
   }
   else{
     [super touchesEnded: touches withEvent: event];
   }
}

Answer 3

改用点击手势识别器：

UITapGestureRecognizer *recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(touch)];
[recognizer setNumberOfTapsRequired:1];
[recognizer setNumberOfTouchesRequired:1];
[scrollView addGestureRecognizer:recognizer];