连续动画调用不起作用

连续动画调用不起作用

我

print

在您的

animateFinished

方法中添加了几行，以查看发生了什么：

func animateFinished(textToDisplay: String, footerBtn: UIButton, footerImg: UIImageView) {    //Should cancel any current animation    print("Remove animations")    footerBtn.layer.removeAllAnimations()    print("Animations removed")    footerBtn.alpha = 0    footerBtn.setTitle(textToDisplay, forState: UIControlState.Normal)    footerBtn.titleLabel!.font = UIFont(name: "HelveticaNeue-Regular", size: 18)    footerBtn.setTitleColor(UIColor(red: 255/255.0, green: 255/255.0, blue: 255/255.0, alpha: 1.0), forState: UIControlState.Normal)    //footerBtn.backgroundColor = UIColor(red: 217/255.0, green: 217/255.0, blue: 217/255.0, alpha: 1.0)    print("Initial animation setup completed")    UIView.animateKeyframesWithDuration(3.0 , delay:0.0, options: UIViewKeyframeAnimationOptions.CalculationModeLinear, animations: { UIView.addKeyframeWithRelativeStartTime(0.0, relativeDuration:0.10, animations:{     footerImg.alpha = 0.01 //Img fades out     footerBtn.backgroundColor = UIColor(red: 46/255.0, green: 103/255.0, blue: 00/255.0, alpha: 0.6) //Bg turns to green }) UIView.addKeyframeWithRelativeStartTime(0.10, relativeDuration:0.30, animations:{     footerBtn.alpha = 1 //Text and green bg fades in     footerBtn.backgroundColor = UIColor(red: 46/255.0, green: 173/255.0, blue: 11/255.0, alpha: 0.6) //BG turns greener }) UIView.addKeyframeWithRelativeStartTime(0.40, relativeDuration:0.50, animations:{     footerBtn.alpha = 0.01 //Text fades out & bg fade out })        },        completion: {  finished in print("Completion block started") footerImg.alpha = 1 footerBtn.alpha = 1 footerBtn.backgroundColor = UIColor.clearColor() footerBtn.setTitleColor(UIColor(red: 55/255.0, green: 55/255.0, blue: 55/255.0, alpha: 1.0), forState: UIControlState.Normal) footerBtn.titleLabel!.font = UIFont(name: "HelveticaNeue-Light", size: 18) footerBtn.setTitle("", forState: UIControlState.Normal) //Completion blocks sets values back to norm print("Completion block finished")        }    )}//End of 'Finished' animation

如果您允许动画运行完成，则将显示日志，如您所愿：

Remove animationsAnimations removedInitial animation setup completedCompletion block startedCompletion block finished

但是，如果在动画过程中点击按钮，则会看到以下内容：

Remove animationsAnimations removedInitial animation setup completedRemove animationsAnimations removedInitial animation setup completedCompletion block startedCompletion block finishedCompletion block startedCompletion block finished

发生了什么情况，

removeAllAnimations

导致在完成第二个调用的初始设置 之后 ，但 在 执行第二个动画 之前
，执行了完成块（对于第一个调用）。因此，例如，在第二个动画期间，按钮标题为“”。

解决方法相对简单：如果动画尚未完成，请不要执行完成块：

        completion: {  finished in if (!finished) {     return } print("Completion block started") footerImg.alpha = 1 footerBtn.alpha = 1 footerBtn.backgroundColor = UIColor.clearColor() footerBtn.setTitleColor(UIColor(red: 55/255.0, green: 55/255.0, blue: 55/255.0, alpha: 1.0), forState: UIControlState.Normal) footerBtn.titleLabel!.font = UIFont(name: "HelveticaNeue-Light", size: 18) footerBtn.setTitle("", forState: UIControlState.Normal) print("Completion block finished") //Completion blocks sets values back to norm        }

另外，根据《 Shripada》，您将需要从footerImg和footerBtn中移除动画，并使用以下命令：

footerImg.layer.removeAllAnimations()

在方法开始时。