是否有可能取消一个UIView动画,而它正在进行中?或者我必须降到CA级别?

例如,我做过这样的事情(可能设置了一个结束动画动作):

[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:duration];
[UIView setAnimationCurve: UIViewAnimationCurveLinear];
// other animation properties

// set view properties

[UIView commitAnimations];

但是在动画完成之前,我得到动画结束事件,我想取消它(缩短它)。这可能吗?在谷歌上搜索一下,会发现一些人问了同样的问题,但没有答案——还有一两个人猜测这是不可能的。


当前回答

CALayer * pLayer = self.layer.presentationLayer;
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView animateWithDuration:0.001 animations:^{
    self.frame = pLayer.frame;
}];

其他回答

以上这些方法都不能解决我的问题,但是这个方法有帮助:UIView动画会立即设置属性,然后将其动画化。当表示层与模型(set属性)匹配时,它会停止动画。

我解决了我的问题,那就是“我想从你出现的地方动画”(“你”指的是视图)。如果你想要那样,那么:

添加QuartzCore。 CALayer * pLayer = theView.layer.presentationLayer;

将位置设置为表示层

我使用了一些选项,包括UIViewAnimationOptionOverrideInheritedDuration

但由于苹果的文档是模糊的,我不知道它是否真的覆盖其他动画时使用,或只是重置计时器。

[UIView animateWithDuration:blah... 
                    options: UIViewAnimationOptionBeginFromCurrentState ... 
                    animations: ^ {
                                   theView.center = CGPointMake( pLayer.position.x + YOUR_ANIMATION_OFFSET, pLayer.position.y + ANOTHER_ANIMATION_OFFSET);
                   //this only works for translating, but you get the idea if you wanna flip and scale it. 
                   } completion: ^(BOOL complete) {}];

现在这应该是一个不错的解决方案。

我也有同样的问题;api没有任何东西来取消某些特定的动画。的

+ (void) setAnimationsEnabled:(BOOL)启用

禁用所有动画,因此不为我工作。有两种解决方案:

1)使你的动画对象成为子视图。然后,当你想要取消该视图的动画时,删除该视图或隐藏它。很简单,但是你需要重新创建没有动画的子视图如果你需要保持它在视图中。

2)只重复一个anim,并在需要时创建一个委托选择器重新启动anim,如下所示:

-(void) startAnimation {
NSLog(@"startAnim alpha:%f", self.alpha);
[self setAlpha:1.0];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:1.0];
[UIView setAnimationRepeatCount:1];
[UIView setAnimationRepeatAutoreverses:YES];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:@selector(pulseAnimationDidStop:finished:context:)];
[self setAlpha:0.1];
[UIView commitAnimations];
}

- (void)pulseAnimationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context {
if(hasFocus) {
    [self startAnimation];
} else {
    self.alpha = 1.0;
}
}

-(void) setHasFocus:(BOOL)_hasFocus {
hasFocus = _hasFocus;
if(hasFocus) {
    [self startAnimation];
}
}

问题2)总是延迟停止动画,因为它完成当前的动画周期。

希望这能有所帮助。

Even if you cancel the animation in the ways above animation didStopSelector still runs. So if you have logic states in your application driven by animations you will have problems. For this reason with the ways described above I use the context variable of UIView animations. If you pass the current state of your program by the context param to the animation, when the animation stops your didStopSelector function may decide if it should do something or just return based on the current state and the state value passed as context.

[UIView setAnimationsEnabled:NO];
// your code here
[UIView setAnimationsEnabled:YES];

当我使用UIStackView动画时,除了removeAllAnimations()之外,我需要将一些值设置为初始值,因为removeAllAnimations()可以将它们设置为不可预知的状态。我有stackView与view1和view2在里面,一个视图应该是可见的和一个隐藏:

public func configureStackView(hideView1: Bool, hideView2: Bool) {
    let oldHideView1 = view1.isHidden
    let oldHideView2 = view2.isHidden
    view1.layer.removeAllAnimations()
    view2.layer.removeAllAnimations()
    view.layer.removeAllAnimations()
    stackView.layer.removeAllAnimations()
    // after stopping animation the values are unpredictable, so set values to old
    view1.isHidden = oldHideView1 //    <- Solution is here
    view2.isHidden = oldHideView2 //    <- Solution is here

    UIView.animate(withDuration: 0.3,
                   delay: 0.0,
                   usingSpringWithDamping: 0.9,
                   initialSpringVelocity: 1,
                   options: [],
                   animations: {
                    view1.isHidden = hideView1
                    view2.isHidden = hideView2
                    stackView.layoutIfNeeded()
    },
                   completion: nil)
}