动画UIViewPropertyAnimator的fractionComplete模糊背景

Question

因此，当您在主屏幕上向下滚动并且模糊背景时，我使用新的UIViewPropertyAnimator和UIVisualEffectView实现与Spotlight搜索相同的功能。

我使用fractionComplete属性来设置在平移UIView时需要模糊多少。

animator = UIViewPropertyAnimator(duration: 1, curve: .linear) { 
     self.blurEffectView.effect = nil 
    } 

并且模糊量被改变为0.0-1.0之间的值。

 animator?.fractionComplete = blurValue 

但是，当我取消移动手势我想模糊动画从那里是没有模糊回（例如〜 - > 1.0）与类似0.4毫秒的持续时间。

现在我只是在平移手势被取消时将fractionComplete设置为1.0。相反，我想为它制作动画。
我曾尝试UIView.animate（withDuration ..但它不影响UIViewPropertyAnimators fractionComplete，和那模糊的UIVisualEffectView的唯一途径。

任何想法？

Answer 1

看来fractionComplete有错误（我的＃2问题：UIViewPropertyAnimator does not update the view when expected），rdar://30856746酒店只设置从inactive到active状态，但不更新视图，因为（我认为）有不触发另一内部状态

要。解决你可以做的问题是：

animator.startAnimation() // This will change the `state` from inactive to active 
animator.pauseAnimation() // This will change `isRunning` back to false, but the `state` will remain as active 

// Now any call of `fractionComplete` should update your view correctly! 
animator.fractionComplete = /* your value here */ 

这里是一个操场片断打转转：

let liveView = UIView(frame: CGRect(x: 0, y: 0, width: 400, height: 50)) 
liveView.backgroundColor = .white 

PlaygroundPage.current.needsIndefiniteExecution = true 
PlaygroundPage.current.liveView = liveView 

let square = UIView(frame: CGRect(x: 0, y: 0, width: 50, height: 50)) 
square.backgroundColor = .red 

liveView.addSubview(square) 

let animator = UIViewPropertyAnimator.init(duration: 5, curve: .linear) 

animator.addAnimations { 

    square.frame.origin.x = 350 
} 

let blurView = UIVisualEffectView(effect: UIBlurEffect(style: .dark)) 
blurView.frame = liveView.bounds 

liveView.addSubview(blurView) 

animator.addAnimations { 

    blurView.effect = nil 
} 

// If you want to restore the blur after it was animated, you have to 
// safe a reference to the effect which is manipulated 
let effect = blurView.effect 

animator.addCompletion { 
    // In case you want to restore the blur effect 
    if $0 == .start { blurView.effect = effect } 
} 

animator.startAnimation() 
animator.pauseAnimation() 

DispatchQueue.main.asyncAfter(deadline: .now() + 2) { 

    animator.fractionComplete = 0.5 
} 

DispatchQueue.main.asyncAfter(deadline: .now() + 4) { 

    // decide the direction you want your animation to go. 
    // animator.isReversed = true 
    animator.startAnimation() 
} 

Answer 2

如果你还在寻找一种方式来实际动画fractionComplete不使用滑块或手势，我是对使用CADisplayLink的结果非常满意。你可以在这里看到我的结果：https://gist.github.com/vegather/07993d15c83ffcd5182c8c27f1aa600b