UIScreenEdgePanGestureRecognizer触发多次

Question

我在UIViewController上的viewDidLoad中有以下代码:

UIScreenEdgePanGestureRecognizer *edgeRecognizer = [[UIScreenEdgePanGestureRecognizer alloc] initWithTarget:self action:@selector(handleRightEdgeSwipe:)];
edgeRecognizer.edges = UIRectEdgeRight;
[self.view addGestureRecognizer:edgeRecognizer];

目的是在检测到右边缘手势时触发视图滑入.

-(void)handleRightEdgeSwipe:(UIGestureRecognizer*)sender
{
NSLog(@"Showing Side Bar");
[self presentPanelViewController:_lightPanelViewController withDirection:MCPanelAnimationDirectionRight];
}

但是我看到"handleRightEdgeSwipe"功能被多次触发 - 有时是5次,这使侧边栏视图应该平滑地动画滑入闪光灯多次.

(注意:我尝试触发视图从UIButton出现,它工作正常).

为什么右边手势会多次触发,我该如何解决？

Answer 1

如上所述,随着GestureRecognizer状态的变化,UIScreenEdgePanGestureRecognizer会多次调用您的操作.请参阅UIGestureRecognizer类的state属性的文档.所以,在你的情况下,我相信你正在寻找的答案是检查状态是否"结束".从而:

-(void)handleRightEdgeSwipe:(UIGestureRecognizer*)sender
{
    if (sender.state == UIGestureRecognizerStateEnded)
    {
        NSLog(@"Showing Side Bar");
        [self presentPanelViewController:_lightPanelViewController withDirection:MCPanelAnimationDirectionRight];
   }
}

Answer 2

这个手势不是单次事件，而是连续的。

handleRightEdgeSwipe:sender.state每当发生变化或触摸移动时就会调用一次。您必须UIButton根据手势移动state和locationInView:。