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上调用.我想让它在touchBegan上调用.

尝试touchesBegan:withEvent:但它没有任何接触.有人有线索吗？

Answer 1

改为使用Tap Gesture识别器:

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

要么

制作你的subClass UIScrollView 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 2

改为使用Tap Gesture识别器:

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

Answer 3

我认为你必须将UIScrollView子类化才能做到这一点.

touchesBegan:withEvent:仅发送到UIView的子类.您可以在控制器中实现touchesBegan:withEvent:对吧？如果是这样,它将无法在那里工作......

或者,如果您在UIScrollView中放置了UIView的子类(您编写的),您也可以从那里捕获touchesBegan事件(但仅当用户触摸该特定子视图时).默认情况下,UIScrollView会将触摸传递给其子视图(请参阅touchesShouldBegin:withEvent:inContentView:在UIScrollView中).

Answer 4

您还可以在控制器中响应这些事件.为此,您必须定义此功能(在您的控制器中):

- (BOOL)canBecomeFirstResponder {
    return YES;
}

然后,在'viewDidAppear'中,您需要调用'becomeFirstResponder':

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [self becomeFirstResponder];