CAAnimationGroup的最大持续时间值（CFTimeInterval）是多少？

我从那个状态，我CAAnimationGroup两个旋转的动画，一个从零开始，另一种是重复和autoreverses：CAAnimationGroup的最大持续时间值（CFTimeInterval）是多少？

- (void)addWobbleAnimationToView:(UIView *)view amount:(float)amount speed:(float)speed 
{ 
    NSMutableArray *anims = [NSMutableArray array]; 

    // initial wobble 
    CABasicAnimation *startWobble = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"]; 
    startWobble.toValue = [NSNumber numberWithFloat:-amount]; 
    startWobble.duration = speed/2.0; 
    startWobble.beginTime = 0; 
    startWobble.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]; 
    [anims addObject:startWobble]; 

    // rest of wobble 
    CABasicAnimation *wobbleAnim = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"]; 
    wobbleAnim.fromValue = [NSNumber numberWithFloat:-amount]; 
    wobbleAnim.toValue = [NSNumber numberWithFloat:amount]; 
    wobbleAnim.duration = speed; 
    wobbleAnim.beginTime = speed/2.0; 
    wobbleAnim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]; 
    wobbleAnim.autoreverses = YES; 
    wobbleAnim.repeatCount = INFINITY; 
    [anims addObject:wobbleAnim]; 

    CAAnimationGroup *wobbleGroup = [CAAnimationGroup animation]; 
    wobbleGroup.duration = DBL_MAX; // this stops it from working 
    wobbleGroup.animations = anims; 

    [view.layer addAnimation:wobbleGroup forKey:@"wobble"]; 
}

由于CFTimeInterval被定义为double，我尝试设置动画组的持续时间到，但会阻止动画组运行。但是，如果我将它设置为一个很大的数字，例如10000，它运行良好。在CAAnimationGroup的持续时间内，我可以使用的最大数字是多少，以确保其尽可能接近无穷？

UPDATE：看来，如果我把一个非常大的值，例如DBL_MAX/4.0则冻结了一秒钟，然后开始动画。如果我输入值DBL_MAX/20.0，那么开始时的冻结就会小很多。看起来持续这么大的价值会导致它冻结。除了在持续时间内使用非常大的值以外，还有更好的方法吗？

来源

2013-03-27 jowie

你正在努力使这组动画的重复下去吗？ – 2013-03-27 17:19:50

是的，但我只希望小组的第二部分能够永远重复。 – jowie 2013-03-27 17:22:39

你确定需要设置持续时间吗？如果让它未设置会发生什么？ – 2013-03-27 17:25:11

我面对完全一样的问题，现在...我希望有人证明我错了，但唯一合理的方法我看到来处理这种情况是由第一个动画移动到CATransaction，和链接，与使用自动翻转动画：

[CATransaction setCompletionBlock:block];

这并不理想，但能够完成任务。

关于你提到的有关问题的动画来时从后台回来，这就是CoreAnimation框架的经典限制被暂停，许多解决方案已经被提出了它。我解决这个问题的方法是通过简单地在动画的随机点正在重置的动画，通过随机的timeOffset财产。由于该应用程序在后台，用户无法准确地确定动画状态应该是什么。下面是一些代码可以帮助（寻找//RANDOMIZE!!评论）：

[[NSNotificationCenter defaultCenter] addObserver:self 
             selector:@selector(startAnimating) 
              name:UIApplicationWillEnterForegroundNotification 
              object:[UIApplication sharedApplication]]; 

... 

for (CALayer* layer in _layers) 
{ 
    // RANDOMIZE!!! 
    int index = arc4random()%[levels count]; 
    int level = ...; 
    CGFloat xOffset = ...; 

    layer.position = CGPointMake(xOffset, self.bounds.size.height/5.0f + yOffset * level); 

    CGFloat speed = (1.5f + (arc4random() % 40)/10.f); 
    CGFloat duration = (int)((self.bounds.size.width - xOffset)/speed); 

    NSString* keyPath = @"position.x"; 
    CABasicAnimation* anim = [CABasicAnimation animationWithKeyPath:keyPath]; 

    anim.fromValue  = @(xOffset); 
    anim.toValue  = @(self.bounds.size.width); 
    anim.duration  = duration; 
    anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]; 
    // RANDOMIZE!! 
    anim.timeOffset  = arc4random() % (int) duration; 
    anim.repeatCount = INFINITY; 

    [layer removeAnimationForKey:keyPath]; 
    [layer addAnimation:anim forKey:keyPath]; 
    [_animatingLayers addObject:layer]; 
}

来源

2013-08-02 20:22:25 Mazyod

它更易于使用，而不是一组两个独立动画的一个关键帧动画。

- (void)addWobbleAnimationToView:(UIView *)view amount:(CGFloat)amount speed:(NSTimeInterval)speed { 
    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"transform.rotation.z"]; 
    animation.duration = 2 * speed; 
    animation.values = @[ @0.0f, @(-amount), @0.0f, @(amount), @0.0f ]; 
    animation.keyTimes = @[ @0.0, @0.25, @0.5, @0.75, @1.0 ]; 
    CAMediaTimingFunction *easeOut =[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut]; 
    CAMediaTimingFunction *easeIn =[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn]; 
    animation.timingFunctions = @[ easeOut, easeIn, easeOut, easeIn ]; 
    animation.repeatCount = HUGE_VALF; 
    [view.layer addAnimation:animation forKey:animation.keyPath]; 
}

来源

2013-08-02 21:08:07

CAAnimationGroup的最大持续时间值（CFTimeInterval）是多少？

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