PerformSelectorOnMainThread 未等待完成
我有一个执行一些任务的线程。
最后，我想运行一个选择器来隐藏带有动画的图像。
[self performSelectorOnMainThread:@selector(finishUpdate) withObject:nil waitUntilDone:YES];
我将持续时间设置为 10 秒：
- (void) finishUpdate {
UIImageView *myImage = (UIImageView *)[self.view viewWithTag:788];
CGContextRef context = UIGraphicsGetCurrentContext();
[UIView beginAnimations:nil context:context];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationDuration:10.0f];
myImage.frame = CGRectMake(0, 200, 320, 80);
myImage.alpha = 0.0f;
[UIView commitAnimations];
}
但它立即消失，线程立即继续。
你知道如何让我的线程等待或如何显示这个简单的动画吗？
I have a thread which performs some tasks.
At the end I want to run a selector to hide an image with animation.
[self performSelectorOnMainThread:@selector(finishUpdate) withObject:nil waitUntilDone:YES];
I am setting the duration to 10 seconds:
- (void) finishUpdate {
UIImageView *myImage = (UIImageView *)[self.view viewWithTag:788];
CGContextRef context = UIGraphicsGetCurrentContext();
[UIView beginAnimations:nil context:context];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationDuration:10.0f];
myImage.frame = CGRectMake(0, 200, 320, 80);
myImage.alpha = 0.0f;
[UIView commitAnimations];
}
But it is disappearing instantly and the thread continues immediately.
Do you know how to make my thread to wait or how to display this simple animation?
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评论（2）
该方法立即返回是正常行为。
[UIView commitAnimations]不会等待动画完成（或您使用的任何其他方法）。Kristopher Johnson 是对的，您不应该在这种情况下使用
UIGraphicsGetCurrentContext。它在drawRect:中或每当存在有效的图形上下文时使用。动画上下文与图形上下文无关。如果您不需要某些动画委托中的任何上下文，只需传递 NULL 即可。
It is normal behavior for the method to return immediately.
[UIView commitAnimations]does not wait for the animation to finish (or any other method you use).Kristopher Johnson is right that you shouldn't use
UIGraphicsGetCurrentContextin this context. It is used indrawRect:or whenever there is a valid graphics context.The animation context does not relate to a graphics context. Just pass NULL if you don't need any context in some animation delegate.
我没有等待选择器完成，而是使用
sleepForTimeInterval:方法来暂停我的线程，使用与动画相同的持续时间。Instead of waiting for the selector to finish, I used
sleepForTimeInterval:method to pause my thread, using the same duration as my animation.