警告:尝试显示其视图不在窗口层次结构中的*** [英] Warning: Attempt to present *** whose view is not in the window hierarchy

问题描述

当我使用附加的长按手势使用以下代码获取要显示的模态视图时，出现此错误:

I'm receiving this error when I am using an attached long press gesture to get a modal view to come up using the following code:

// Long press to go to settings for one
- (void)longPressOne:(UILongPressGestureRecognizer*)gesture {
       [self performSegueWithIdentifier:@"buttonOne" sender:self];
}

// Long press to go to settings for two
- (void)longPressTwo:(UILongPressGestureRecognizer*)gesture {
    [self performSegueWithIdentifier:@"buttonTwo" sender:self];
}

- (void)viewDidLoad {

    // Add gesture to buttonOne
    UILongPressGestureRecognizer *longPressOne = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressOne:)];
    [self.buttonOne addGestureRecognizer:longPressOne];


    // Add gesture to buttonTwo
    UILongPressGestureRecognizer *longPressTwo = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressTwo:)];
    [self.buttonTwo addGestureRecognizer:longPressTwo];

}

模态选择在视图板上的情节提要中被捆绑到目标视图.我知道在情节提要板上有多个segue时有关于此问题的报告，但是我只有一个，因为我无法通过长按Storyboard上的按钮来创建情节.

The modal segue is hitched up on the storyboard from the viewcontroller to the destination view. I know there are reports of this problem when there are multiple segues on the storyboard, but I just have the one as I can't create a segue from the button for a long press on Storyboard.

知道为什么会这样吗?

推荐答案

我已通过更改处理手势的代码来解决此问题，如下所示:

I have fixed this by altering the code for handling the gestures, as below:

// Long press to go to settings for one
- (void)longPressOne:(UILongPressGestureRecognizer*)gesture {

        if (gesture.state == UIGestureRecognizerStateBegan)
        {
            [self performSegueWithIdentifier:@"buttonOne" sender:self];
        }

}

// Long press to go to settings for two
- (void)longPressTwo:(UILongPressGestureRecognizer*)gesture {
    if (gesture.state == UIGestureRecognizerStateBegan)
    {
        [self performSegueWithIdentifier:@"buttonTwo" sender:self];
    }

}

这似乎可以解决问题.

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