UIActivityIndi​​catorView在CATransition pushViewController之前保持动画

Question

我正试图在我的UIActivityIndi​​catorView上停止动画，方法与使用CATransition fade推送视图控制器的方法相同。

无论停止动画，然后淡入下一个视图控制器，无论我设置持续时间多长，UIActivityIndi​​catorView都会在整个淡入淡出过程中进行动画制作。

我有什么想法可以让旋转停止，然后按同样的方法推送/淡出？

- (void)pushView:(NSNotification *)notification {

    [self.activityIndicator stopAnimating];
    NextViewController* nextViewController = [[NextViewController alloc] init];
    CATransition *transition = [CATransition animation];
    transition.duration = 1.5f;
    transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    transition.type = kCATransitionFade;
    [self.navigationController.view.layer addAnimation:transition forKey:nil];
    [self.navigationController pushViewController:nextViewController animated:NO];

}

修改1

与David的答案一样，如果我使用stopAnimating并延迟了几分之一秒，我就能成功dispatch_after。有没有更好的方法来实现这一目标？：

- (void)pushView:(NSNotification *)notification {

    [self.activityIndicator stopAnimating];

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 0.0001 * NSEC_PER_SEC), dispatch_get_main_queue(), ^(void){
        NextViewController* nextViewController = [[NextViewController alloc] init];
        CATransition *transition = [CATransition animation];
        transition.duration = 1.5f;
        transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
        transition.type = kCATransitionFade;
        [self.navigationController.view.layer addAnimation:transition forKey:nil];
        [self.navigationController pushViewController:nextViewController animated:NO];
    });
}

Answer 1

我之前遇到过类似的事情。您正在运行的内容称为同步执行。在同步执行中，在编译器终止函数a.k.a. }之前，UI不会更新。你怎么解决这个问题？简单。只需运行任何方法即可在异步调度：

中更新UI

- (void)pushView:(NSNotification *)notification {

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void){

dispatch_async(dispatch_get_main_queue(), ^(void){
    [self.activityIndicator stopAnimating];
});

NextViewController* nextViewController = [[NextViewController alloc] init];
CATransition *transition = [CATransition animation];
transition.duration = 1.5f;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = kCATransitionFade;
[self.navigationController.view.layer addAnimation:transition forKey:nil];
[self.navigationController pushViewController:nextViewController animated:NO];

});

}

糟糕！我忘了把其他代码放在一个简单的发送中！尝试编辑的代码，它应该工作！

这样[self.activityIndicator stopAnimating];在优先级线程上运行，而函数中的其余代码在默认优先级线程中运行，同时有效地运行代码，就像你期望的那样到。

干杯！