按钮的 UITapGestureRecognizer 问题

Question

我做了以下事情：

 buttonPlaylistView = [[UIButton alloc] initWithFrame:CGRectMake(self.view.frame.size.width *(urlList.count+1), 0, self.view.frame.size.width, self.view.frame.size.height)];
            buttonPlaylistView.tag = 0;

 UITapGestureRecognizer *doubleTap3 = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)];
            [doubleTap3 setNumberOfTapsRequired:2];
            [buttonPlaylistView addGestureRecognizer:doubleTap3];
            [doubleTap3 release];

-(void) handleDoubleTap:(UITapGestureRecognizer *)sender{
    if(sender.state == UIGestureRecognizerStateEnded)

    int x = [sender tag];
    return;
}

但我在这一行得到SIGAGRT：int x = [sender tag]; 说：

[UITapGestureRecognizer tag]: unrecognized selector sent to instance 0x61280b0
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UITapGestureRecognizer tag]: unrecognized selector sent to instance 0x61280b0'

现在：这是什么问题以及解决方案是什么？谢谢

Answer 1

-(void) handleDoubleTap:(UITapGestureRecognizer *)sender
{
    if(sender.state == UIGestureRecognizerStateEnded)
    {
      int x = [sender.view tag];
    }
}

将解决问题。

Answer 2

UITapGestureRecognizer 没有名为 tag 的属性 - 如您所见，您获得的发送者是 NOT 按钮。您必须直接访问 buttonPlayListView，例如

int x = [buttonPlayListView tag];

或以其他方式记住您要访问的按钮。

Answer 3

即使我很确定您的做法是错误的，将双击手势识别器添加到 UIButton，您仍然可以执行不应该太多的任务为你工作。 你发表了评论

如果我创建了 100 个按钮，我怎么能记得

对于其中一个答案，该答案突出了导致您的 SIGBART 的问题。 UIGestureRecognizer 没有标签属性。

您可以这样做，遍历 [self view] 的所有子视图并找到具有相同 UIGestureRecognizer 的子视图，这不是最漂亮的解决方案，您拥有的子视图越多，循环所需的时间就越长.但它会做你似乎正在寻找的东西，所以如果你要添加。

在您的 handleDoubleTap 函数中，您可以执行以下操作

-(void) handleDoubleTap:(UITapGestureRecognizer *)sender
{
    if(sender.state == UIGestureRecognizerStateEnded)
    {
        int iButtonTag = -1 //This is important later to escape the below for loop as we don't need to needlessly go around in circles
        for(UIView* psubView in [[self view] subviews])
        {
            if( [psubView isKindOfClass:[UIButton class]] )
            {
                UIButton* pButton = (UIButton*)psubView;
                for(UIGestureRecognizer* pGesture in [pButton gestureRecognizers] )
                {
                     if( pGesture == sender )//this is the button we're after
                     {
                         iButtonTag = [pButton tag];
                         break;
                     }
                }
                if( iButton != -1 )//found what we came for
                {
                    break;
                }
             }
        }
        //do what ever it was you needed to do now that you have the views tag, or you could have kept a reference to the button etc.
    }
 }

这应该可以解决您的问题。或者，如果您要向子视图的子视图添加按钮，最好在 NSMutableArray 中跟踪您的 UIButtons，您可以通过创建类属性（或成员变量）并使用'addObject:' NSMutableArray 的函数。然后代替行

for(UIView* psubView in [[self view] subviews])

以上可以换成

for( UIButton* pButton in m_pMutableButtonArray )

其中“m_pMutableButtonArray”是您为存储 UIButtons 的 NSMutableArray 提供的变量名称。这也意味着您将取消以下 if isKindOfClass 测试在下一行。

这应该可以解决您的问题。

Answer 4

为什么要在按钮中放置 UITapGestureRecognizer？该按钮已经为您处理了，并将向您发送回调，您可以使用此 UIControl 方法将目标添加到按钮

- (void)addTarget:(id)target action:(SEL)action forControlEvents:(UIControlEvents)controlEvents