Ios UIVisualEffectView不工作

我正在尝试使用以下代码向视图添加模糊效果：

let visualEffectView = UIVisualEffectView(effect: UIBlurEffect(style: .Light)) as UIVisualEffectView
    visualEffectView.frame = containerView.bounds
    containerView.addSubview(visualEffectView)
    containerView.userInteractionEnabled = true
    containerView.bringSubviewToFront(visualEffectView)
    visualEffectView.alpha = 1.0

然而，我没有看到任何变化

更新

我很抱歉，但我认为我在最初的问题中没有表明我的意图。我想要实现的是这样的目标：

我的视图中有一个

UIImageView

，它占据了整个屏幕。接下来，在屏幕底部，我有一个容器，它是一个

UIView

，其中包含一些按钮等。我想做的是在containerView中添加一个模糊效果，这样它后面的

UIImageView

就会模糊，containerView就在这里。所以基本上我把containerView的alpha设置为0.5，这意味着它是半透明的，我可以看到它后面的图像。我现在想做的是使containerView后面的图像模糊

当前效率：

代码：

extension UIButton{

func setImage(image: UIImage?, inFrame frame: CGRect?, forState state: UIControlState){
    self.setImage(image, forState: state)

    if let frame = frame{
        self.imageEdgeInsets = UIEdgeInsets(
            top: frame.minY - self.frame.minY,
            left: frame.minX - self.frame.minX,
            bottom: self.frame.maxY - frame.maxY,
            right: self.frame.maxX - frame.maxX
        )
    }
}

}



class SingleImageFeedView: UIViewController {

lazy var mainImageView : UIImageView = {
    let imageView = UIImageView()
    imageView.frame = CGRectMake(0, 0, self.view.frame.width, self.view.frame.width * 1.3)
    imageView.contentMode = UIViewContentMode.ScaleAspectFill
    imageView.backgroundColor = UIColor.clearColor()
    imageView.image = UIImage(named: "pizza")
    return imageView
}()

let containerView : UIView = {
    let this = UIView(frame: CGRectMake(0,0, 600,150))
    this.backgroundColor = UIColor.clearColor()
    this.layer.cornerRadius = 5
    this.layer.borderColor = UIColor(red: (69/255.0), green: (209/255.0), blue: (153/255.0), alpha: 1.0).CGColor
    this.layer.borderWidth = 0.5
    return this
}()


let captionAndProfileImageContainerView : UIView = {
    let this = UIView()
    //this.backgroundColor = UIColor(red: (69/255.0), green: (209/255.0), blue: (153/255.0), alpha: 0.0)
    this.backgroundColor = UIColor.clearColor()
    return this
}()

let profilePicImageView : UIImageView = {
    let imageView = UIImageView()
    imageView.frame = CGRectMake(0, 0, 53, 53)
    imageView.backgroundColor = UIColor.clearColor()
    imageView.image = UIImage(named: "pizza")
    imageView.contentMode = UIViewContentMode.ScaleToFill
    return imageView
}()

let captionTextView: UITextView = {
    let textField = UITextView(frame: CGRectMake(0,0, 150, 100))
    textField.textColor = UIColor.whiteColor()
    textField.editable = false
    textField.text = "dwwdwwwwdwddwd"
    textField.backgroundColor = UIColor.clearColor()
    textField.font = UIFont.systemFontOfSize(12.0)
    return textField
}()

let dividerLineView: UIView = {
    let view = UIView()
    view.backgroundColor = UIColor(white: 0.5, alpha: 0.5)
    return view
}()

let commentAndLikesContainerView : UIView = {
   let view = UIView()
    //view.backgroundColor = UIColor(red: (69/255.0), green: (209/255.0), blue: (153/255.0), alpha: 0.0)
    view.backgroundColor = UIColor.clearColor()
    return view
}()

let commentLabel : UILabel = {
    let label = UILabel()
    label.text = "23"
    return label
}()

let likesLabel : UILabel = {
    let label = UILabel()
    label.text = "25"
    return label
}()

let voteUpButton : UIButton = {
    let button = UIButton(frame: CGRectMake(0,0,25,25))
    button.setImage((scaleImage((UIImage(named: "upvote"))!, toSize: CGSizeMake(25, 25))), inFrame: CGRectMake(0,0,25,25), forState: .Normal)
    button.imageView?.contentMode = UIViewContentMode.Center
    button.imageView?.clipsToBounds = true
    button.imageEdgeInsets = UIEdgeInsetsMake(10, 10, 10, 10)
    return button
}()

let voteDownButton : UIButton = {
    let button = UIButton(frame: CGRectMake(0,0,25,25))
    button.setImage((scaleImage((UIImage(named: "upvote"))!, toSize: CGSizeMake(25, 25))), inFrame: CGRectMake(0,0,25,25), forState: .Normal)
    button.imageView?.transform = CGAffineTransformMakeRotation((180.0 * CGFloat(M_PI)) / 180.0)
    button.imageView?.contentMode = UIViewContentMode.Center
    button.imageEdgeInsets = UIEdgeInsetsMake(6, 10, 10, 10)
    button.imageView?.clipsToBounds = true
    return button
}()


let commentButton : UIButton = {
    let button = UIButton(frame: CGRectMake(0,0,25,25))
    button.setImage((scaleImage((UIImage(named: "comment_feed_icon"))!, toSize: CGSizeMake(25, 25))), inFrame: CGRectMake(0,0,25,25), forState: .Normal)
    button.imageView?.contentMode = UIViewContentMode.ScaleAspectFit
    button.imageEdgeInsets = UIEdgeInsetsMake(10, 10, 10, 10)
    button.imageView?.clipsToBounds = true
    return button
}()

override func viewDidLoad() {
    super.viewDidLoad()
    self.view.backgroundColor = UIColor.clearColor()
    setupViews()
}

func setupViews() {
    self.captionAndProfileImageContainerView.addSubview(profilePicImageView)
    self.captionAndProfileImageContainerView.addSubview(captionTextView)

    self.commentAndLikesContainerView.addSubview(voteUpButton)
    self.commentAndLikesContainerView.addSubview(voteDownButton)
    self.commentAndLikesContainerView.addSubview(commentButton)
    self.commentAndLikesContainerView.addSubview(commentLabel)
    self.commentAndLikesContainerView.addSubview(likesLabel)

    self.containerView.addSubview(captionAndProfileImageContainerView)
    self.containerView.addSubview(dividerLineView)
    self.containerView.addSubview(commentAndLikesContainerView)




    self.view.addSubview(containerView)
    self.view.bringSubviewToFront(containerView)
    self.view.addSubview(mainImageView)
    self.containerView.bringSubviewToFront(captionAndProfileImageContainerView)
    self.containerView.bringSubviewToFront(dividerLineView)
    self.containerView.bringSubviewToFront(commentAndLikesContainerView)


    profilePicImageView.translatesAutoresizingMaskIntoConstraints = false
    captionTextView.translatesAutoresizingMaskIntoConstraints = false
    voteDownButton.translatesAutoresizingMaskIntoConstraints = false
    containerView.translatesAutoresizingMaskIntoConstraints = false
    voteUpButton.translatesAutoresizingMaskIntoConstraints = false
    commentLabel.translatesAutoresizingMaskIntoConstraints = false
    commentButton.translatesAutoresizingMaskIntoConstraints = false
    commentAndLikesContainerView.translatesAutoresizingMaskIntoConstraints = false
    captionAndProfileImageContainerView.translatesAutoresizingMaskIntoConstraints = false
    likesLabel.translatesAutoresizingMaskIntoConstraints = false
    dividerLineView.translatesAutoresizingMaskIntoConstraints = false
    mainImageView.translatesAutoresizingMaskIntoConstraints = false


    //main imageview constraints
    self.view.addConstraint(NSLayoutConstraint(item: mainImageView, attribute: .Top, relatedBy: .Equal, toItem: self.view, attribute: .Top, multiplier: 1, constant: 35))
    self.view.addConstraint(NSLayoutConstraint(item: mainImageView, attribute: .Leading, relatedBy: .Equal, toItem: self.view, attribute: .Leading, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: mainImageView, attribute: .Trailing, relatedBy: .Equal, toItem: self.view, attribute: .Trailing, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: mainImageView, attribute: .CenterX, relatedBy: .Equal, toItem: self.view, attribute: .CenterX, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: mainImageView, attribute: .Bottom, relatedBy: .Equal, toItem: self.view, attribute: .Bottom, multiplier: 1, constant: 0))
    self.view.sendSubviewToBack(mainImageView)


    //containerview constraints

    self.view.addConstraint(NSLayoutConstraint(item: containerView, attribute: .Bottom, relatedBy: .Equal, toItem: self.view, attribute: .Bottom, multiplier: 1, constant: -10))
    self.view.addConstraint(NSLayoutConstraint(item: containerView, attribute: .Leading, relatedBy: .Equal, toItem: self.view, attribute: .Leading, multiplier: 1, constant: 10))
    self.view.addConstraint(NSLayoutConstraint(item: containerView, attribute: .Trailing, relatedBy: .Equal, toItem: self.view, attribute: .Trailing, multiplier: 1, constant: -10))
    self.view.addConstraint(NSLayoutConstraint(item: containerView, attribute: .Top, relatedBy: .Equal, toItem: self.view, attribute: .Bottom, multiplier: 1, constant: -160))

    //caption and profilepic constraints

    self.view.addConstraint(NSLayoutConstraint(item: captionAndProfileImageContainerView, attribute: .Top, relatedBy: .Equal, toItem: containerView, attribute: .Top, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: captionAndProfileImageContainerView, attribute: .Leading, relatedBy: .Equal, toItem: containerView, attribute: .Leading, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: captionAndProfileImageContainerView, attribute: .Trailing, relatedBy: .Equal, toItem: containerView, attribute: .Trailing, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: captionAndProfileImageContainerView, attribute: .Bottom, relatedBy: .Equal, toItem: containerView, attribute: .Bottom, multiplier: 1, constant: -50))

    self.view.addConstraintsWithFormat("H:|-8-[v0(50)]", views: profilePicImageView)
    self.view.addConstraintsWithFormat("V:|-35-[v0(50)]", views: profilePicImageView)
    profilePicImageView.layer.cornerRadius = 25
    profilePicImageView.layer.masksToBounds = true



    self.view.addConstraint(NSLayoutConstraint(item: captionTextView, attribute: .Top, relatedBy: .Equal, toItem: captionAndProfileImageContainerView, attribute: .Top, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: captionTextView, attribute: .Leading, relatedBy: .Equal, toItem: profilePicImageView, attribute: .Trailing, multiplier: 1, constant: 10))
    self.view.addConstraint(NSLayoutConstraint(item: captionTextView, attribute: .Trailing, relatedBy: .Equal, toItem: captionAndProfileImageContainerView, attribute: .Trailing, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: captionTextView, attribute: .Bottom, relatedBy: .Equal, toItem: captionAndProfileImageContainerView, attribute: .Bottom, multiplier: 1, constant: 0))

    //likes and comments and divider


    self.view.addConstraint(NSLayoutConstraint(item: commentAndLikesContainerView, attribute: .Top, relatedBy: .Equal, toItem: captionAndProfileImageContainerView, attribute: .Bottom, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: commentAndLikesContainerView, attribute: .Leading, relatedBy: .Equal, toItem: containerView, attribute: .Leading, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: commentAndLikesContainerView, attribute: .Trailing, relatedBy: .Equal, toItem: containerView, attribute: .Trailing, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: commentAndLikesContainerView, attribute: .Bottom, relatedBy: .Equal, toItem: containerView, attribute: .Bottom, multiplier: 1, constant: 0))


    self.view.addConstraint(NSLayoutConstraint(item: voteUpButton, attribute: .Top, relatedBy: .Equal, toItem: commentAndLikesContainerView, attribute: .Top, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: voteUpButton, attribute: .Leading, relatedBy: .Equal, toItem: commentAndLikesContainerView, attribute: .Leading, multiplier: 1, constant: 10))


    self.view.addConstraint(NSLayoutConstraint(item: likesLabel, attribute: .Top, relatedBy: .Equal, toItem: commentAndLikesContainerView, attribute: .Top, multiplier: 1, constant: 10))
    self.view.addConstraint(NSLayoutConstraint(item: likesLabel, attribute: .Leading, relatedBy: .Equal, toItem: voteUpButton, attribute: .Trailing, multiplier: 1, constant: 10))

    self.view.addConstraint(NSLayoutConstraint(item: voteDownButton, attribute: .Top, relatedBy: .Equal, toItem: commentAndLikesContainerView, attribute: .Top, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: voteDownButton, attribute: .Leading, relatedBy: .Equal, toItem: likesLabel, attribute: .Trailing, multiplier: 1, constant: 10))

    self.view.addConstraint(NSLayoutConstraint(item: commentButton, attribute: .Top, relatedBy: .Equal, toItem: commentAndLikesContainerView, attribute: .Top, multiplier: 1, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: commentButton, attribute: .Leading, relatedBy: .Equal, toItem: voteDownButton, attribute: .Trailing, multiplier: 1, constant: 30))

    self.view.addConstraint(NSLayoutConstraint(item: commentLabel, attribute: .Top, relatedBy: .Equal, toItem: commentAndLikesContainerView, attribute: .Top, multiplier: 1, constant: 10))
    self.view.addConstraint(NSLayoutConstraint(item: commentLabel, attribute: .Leading, relatedBy: .Equal, toItem: commentButton, attribute: .Trailing, multiplier: 1, constant: 10))



    if !UIAccessibilityIsReduceTransparencyEnabled() {
        self.containerView.backgroundColor = UIColor.clearColor()

        let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.Dark)
        let blurEffectView = UIVisualEffectView(effect: blurEffect)
        //always fill the view
        blurEffectView.frame = containerView.bounds
        blurEffectView.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]

        self.containerView.insertSubview(blurEffectView, atIndex: 1) //if you have more UIViews, use an insertSubview API to place it where needed


    }
    else {
        self.view.backgroundColor = UIColor(red: (69/255.0), green: (209/255.0), blue: (153/255.0), alpha: 0.5)
    }



    containerView.clipsToBounds = true

}


}

---

我用UIImageView和容器做了一个简单的项目。将模糊应用于容器会模糊下面的照片。容器背景在情节提要中设置为透明

class ViewController: UIViewController {
override func viewDidLoad() {
    super.viewDidLoad()

    let containerView : UIView = {
        let this = UIView(frame: CGRectMake(100,200, 200,200))
        this.backgroundColor = UIColor.clearColor()
        this.layer.cornerRadius = 5
        this.layer.borderColor = UIColor(red: (69/255.0), green: (209/255.0), blue: (153/255.0), alpha: 1.0).CGColor
        this.layer.borderWidth = 0.5
        return this
    }()

    let visualEffectView = UIVisualEffectView(effect: UIBlurEffect(style: .Light))

    visualEffectView.frame = containerView.bounds

    self.view.addSubview(containerView)
    containerView.insertSubview(visualEffectView, atIndex: 0)
    let secondImg = UIImageView(image: UIImage(named: "swift_tut.png"))

    secondImg.frame = CGRectMake(150,250, 200,200)

    self.view.addSubview(secondImg)
    self.view.bringSubviewToFront(containerView)





    // Do any additional setup after loading the view, typically from a nib.
}

---

试试这个代码，为我工作

 if !UIAccessibilityIsReduceTransparencyEnabled() {
         self.view.backgroundColor = UIColor.clearColor()

        let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.Dark)
        let blurEffectView = UIVisualEffectView(effect: blurEffect)
        //always fill the view
        blurEffectView.frame = self.view.bounds
        blurEffectView.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]

        self.view.insertSubview(blurEffectView, atIndex: 1) //if you have more UIViews, use an insertSubview API to place it where needed


    }
    else {
        self.view.backgroundColor = UIColor.blackColor()
    }

---

唯一的问题是containerView是一个uiview而不是一个imageview，不确定这是否有区别伙计们，请检查我的编辑，我提供了更多信息，如果我将此添加到containerView，整个内容将变为灰色，我想我需要以某种方式在其后面的相同位置创建另一个视图，并将其添加到该视图中，我不确定我是否在我的设备上发布了问题的图片请确保您的容器视图和关联的视图控制器背景都已设置为清除。我可以通过修改容器或视图控制器上的背景色来复制您的问题。我将整个代码添加到问题中，我将所有可能的背景色设置为我可以找到的

clearColor（）

，请看一看，也许您会发现我遗漏的内容，请检查我的编辑，我提供了更多的信息，但不涉及主题。您可以使用SnapKit以编程方式添加约束—这更容易；D