7

我有一个调用 animateWithDuration 代码的按钮，该代码淡出图像，淡出文本和新的 bg 颜色，然后重置为正常。动画需要几秒钟才能完成并且效果很好。

然而！有一个问题：

有时会在动画结束之前再次按下此按钮。发生这种情况时，我希望当前动画停止并重新开始。

研究的解决方案不起作用

根据我的阅读，解决方案应该很简单，只需导入 QuartzCore 并添加：

button.layer.removeAllAnimations()

这确实删除了动画，但新的/第二个动画完全搞砸了。应该隐藏的图像没有，文字永远不会出现，颜色过渡都是错误的。发生了什么！？！

//Animate Finished feedback in footer bar
func animateFinished(textToDisplay: String, footerBtn: UIButton, footerImg: UIImageView) {

    //Should cancel any current animation
    footerBtn.layer.removeAllAnimations()

    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)

    UIView.animateWithDuration(0.5, delay: 0.0, options: nil, animations: {
        footerImg.alpha = 0.01 //Img fades out
        footerBtn.backgroundColor = UIColor(red: 46/255.0, green: 163/255.0, blue: 00/255.0, alpha: 0.6)
        }
        , completion: { finished in

            UIView.animateWithDuration(0.5, delay: 0.0, options: nil, animations: {
                footerBtn.alpha = 1 //Text fades in
                footerBtn.backgroundColor = UIColor(red: 46/255.0, green: 208/255.0, blue: 11/255.0, alpha: 0.6)
                }
                , completion: { finished in

                    UIView.animateWithDuration(0.5, delay: 1.0, options: nil, animations: {
                        footerBtn.alpha = 0.01 //Text fades out
                        footerBtn.backgroundColor = UIColor(red: 46/255.0, green: 173/255.0, blue: 00/255.0, alpha: 0.6)
                        }
                        , completion: { finished in

                            UIView.animateWithDuration(0.5, delay: 0.0, options: nil, animations: {
                                footerImg.alpha = 1 //Img fades in
                                }
                                , completion: { finished in
                                    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)
                                    footerBtn.alpha = 1
                                    //Completion blocks sets values back to norm
                            })
                    })
            })
    })
}//End of animation

@Shripada 建议我切换到关键帧以获得更易读的代码。关键帧格式如下。它没有解决动画中断问题。如果您可以解决嵌套或关键帧格式的问题，请发布！

func animateFinished(textToDisplay: String, footerBtn: UIButton, footerImg: UIImageView) {
    //Should cancel any current animation
    footerBtn.layer.removeAllAnimations()

    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)

    UIView.animateKeyframesWithDuration(3.0 /*Total*/, 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
            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
        }
    )
}//End of 'Finished' animation
4

2 回答 2

3

我print在您的方法中添加了一些行animateFinished，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 /*Total*/, 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，日志将显示，如您所料：

Remove animations
Animations removed
Initial animation setup completed
Completion block started
Completion block finished

但是如果你在动画期间点击按钮，你会看到：

Remove animations
Animations removed
Initial animation setup completed
Remove animations
Animations removed
Initial animation setup completed
Completion block started
Completion block finished
Completion block started
Completion block finished

在完成第二次调用的初始设置之后，但在进行第二次动画之前，removeAllAnimations导致执行完成块（对于第一次调用）是怎么回事。因此，例如，在第二个动画期间按钮标题为“”。

修复相对简单：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
        }

此外，根据 Shripada，您需要从 footerImg 和 footerBtn 中删除动画，其中：

footerImg.layer.removeAllAnimations()

在方法的开始。

于 2015-09-25T14:08:30.500 回答
2

您应该避免使用连续动画的完成块在这种嵌套中对动画进行排序。这不仅使其高度不可读，而且还难以理解和解决您提到的问题。

有一个更好的选择，称为关键帧动画，您应该考虑使用它（iOS 7 及更高版本可用）。

animateKeyFramesWithDuration:delay:options:animation:completion

参考文档

您的动画代码可以使用关键帧重写（PS：我没有对此进行测试，只是为您的参考输入）-

func animateFinished(textToDisplay: String, footerBtn: UIButton, footerImg: UIImageView) {
    //Should cancel any current animation
    footerBtn.layer.removeAllAnimations()
    footerImg.layer.removeAllAnimations()
    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)

    UIView.animateKeyframesWithDuration(3.0 /*Total*/, 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(0.0, 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(0.0, relativeDuration:0.50, animations:{
                footerBtn.alpha = 0.01 //Text fades out & bg fade out
            })

        },
        completion: {  finished in
            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
        }
    )
}//End of 'Finished' animation

尽管它是 obj c，但也请参考此链接，非常有用。 http://www.raizlabs.com/dev/2015/01/uiview-animation-sequencing-and-grouping-techniques/

于 2015-09-08T05:09:36.307 回答