呈现具有模糊效果的视图控制器

Question

我正在以模糊背景效果模式呈现视图控制器.iOS 10/XCode 8引入了我的动画问题.这是演示代码:

let modalVC = ModalViewController(nibName: "ModalViewController", bundle: nil)
modalVC.modalTransitionStyle = .CrossDissolve
modalVC.modalPresentationStyle = .OverFullScreen
presentViewController(modalVC, animated: true, completion: nil)

viewDidLoad()在ModalViewController中添加函数模糊:

let blurEffect = UIBlurEffect(style: .Light)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.frame = view.bounds
blurEffectView.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]

view.addSubview(blurEffectView)
view.sendSubviewToBack(blurEffectView)

该ModalViewController有一个明确的背景下,我加入了BlurEffectView一个黑暗的模糊效果.以编程方式使用上一个代码段和Interface Builder进行尝试.

在iOS 8和9上,.CrossDissolve转换处理了"淡入淡出",但在iOS 10(设备和模拟器)上进行测试后,视图显示为黑色半透明背景颜色而不是模糊.

在之后.CrossDissolve动画完成,背景颜色变为实际的模糊效果的背景.任何想法为什么会这样？

还尝试layoutIfNeeded()在viewDidLoad()模态视图控制器的开头和结尾添加没有任何运气.我正在使用swift 2.3

Answer 1

嗨,

你需要创建一个新的UIViewControllerAnimatedTransitioning.

然后animateTransition(using transitionContext: UIViewControllerContextTransitioning)你需要编写动画代码.

现在在iOS的10,您可以使用UIViewPropertyAnimator,以动画BlurRadius的UIVisualBlurEffect.

结果:

这里有一个用法示例:https://github.com/PierrePerrin/PPBlurModalPresentation

第一

您需要创建模糊过渡

    class BlurModalPresentation: NSObject,UIViewControllerAnimatedTransitioning {


        func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval{

            return 0.5
        }

//This is the blur view used for transition
        var blurView = UIVisualEffectView(effect: UIBlurEffect(style: UIBlurEffectStyle.light))
        var destinationView : UIView!
        var animator: UIViewPropertyAnimator?

        // This method can only  be a nop if the transition is interactive and not a percentDriven interactive transition.
        func animateTransition(using transitionContext: UIViewControllerContextTransitioning){

            let containerView = transitionContext.containerView

            _ = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from)
            let toVc = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to)

            destinationView = toVc!.view
            destinationView.alpha = 0.0

//Here we add the blur view and set it effect to nil
            blurView.effect = nil
            blurView.frame = containerView.bounds

            self.blurTransition(transitionContext) { 

                self.unBlur(transitionContext, completion: { 

                    self.blurView.removeFromSuperview()
                    transitionContext.completeTransition(true)
                })
            }

            containerView.addSubview(toVc!.view)
            containerView.addSubview(blurView)
        }

        //This methods add the blur to our view and our destinationView
        func blurTransition(_ context : UIViewControllerContextTransitioning,completion: @escaping () -> Void){

            UIViewPropertyAnimator.runningPropertyAnimator(withDuration: self.transitionDuration(using: context)/2, delay: 0, options: UIViewAnimationOptions.curveLinear, animations: {

                self.destinationView.alpha = 0.5
                  self.blurView.effect = UIBlurEffect(style: UIBlurEffectStyle.light)
            }, completion: { (position) in
                completion()
            })

        }
        //This Method remove the blur view with an animation
        func unBlur(_ context : UIViewControllerContextTransitioning,completion: @escaping () -> Void){

            UIViewPropertyAnimator.runningPropertyAnimator(withDuration: self.transitionDuration(using: context) / 2, delay:0, options: UIViewAnimationOptions.curveLinear, animations: {

                self.destinationView.alpha = 1.0
                self.blurView.effect = nil
            }, completion: { (position) in
                completion()
            })
        }

    }

然后

您需要在以下位置设置转换委派ViewController:

import UIKit

class ViewController: UIViewController,UIViewControllerTransitioningDelegate {

    let blurModalPresentation = BlurModalPresentation()

    override func viewDidLoad() {
        super.viewDidLoad()

    }

    func showVC(){

        let str = self.storyboard!
        let vc = str.instantiateViewController(withIdentifier: "YourViewControllerIdentifier")
        vc.transitioningDelegate = self
        self.present(vc, animated: true, completion: nil)
    }


    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
    }

    func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning?{

        return blurModalPresentation
    }


    func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning?{

        return blurModalPresentation
    }

}

Answer 2

首先，我将此解决方案视为临时解决方法，因为我必须假设这个新引入的行为是一个错误，并将在未来的更新中修复。这使得它稍微不那么明显，因为模糊效果是在动画期间而不是之后突然出现的。仍然不如 iOS 9 及其后版本那么好，但稍微好一些。

1. 显示没有动画的视图控制器：

   presentViewController(modalVC, animated: false, completion: nil)
   

2. 从一开始就隐藏你的视图：

   override func viewDidLoad() {
       super.viewDidLoad()
   
       view.alpha = 0
   }
   

3. 手动应用动画：

   override func viewWillAppear(animated: Bool) {
       super.viewWillAppear(animated)
   
       UIView.animateWithDuration(0.25) {
           self.view.alpha = 1
       }
   }
   
   override func viewWillDisappear(animated: Bool) {
       super.viewWillDisappear(animated)
   
       UIView.animateWithDuration(0.25) {
           self.view.alpha = 0
       }
   }