应用升级的项目之后，更新代码的xcode 9和迅速4

Question

应用崩溃后震落XCODE 9和迅速4.同时在

backview.addsubview(stackview) 

应用调试与的libC++ abi.dylib崩溃：终止与未捕获类型为NSException的异常。代码在swift 3中运行完美。但是在迁移到swift 4后，它崩溃了。这是我的全部功能。

var isAlreadyThere = false 

    if let audioView = self.view.subviews.filter (
     { $0.tag == 123456}).first { 

     audioView.tag = 123456 
     isAlreadyThere = true 
    } 

    if isAlreadyThere { 
     return 
    } 

    let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.light) 
    let backView = UIVisualEffectView(effect: blurEffect) 
    backView.tag = 123456 
    backView.frame = CGRect(x: 0, y: self.view.frame.height+35 , width: self.view.frame.width, height: 40) 
    backView.autoresizingMask = [.flexibleWidth, .flexibleHeight] 
    view.addSubview(backView) 

    pauseButton = UIButton(type: .custom) 
    pauseButton.titleLabel?.font = Util.getFontSize() 
    pauseButton.setTitle("Pause", for: .normal) 
    pauseButton.setTitleColor(UIColor.black, for: .normal) 
    pauseButton.addTarget(self, action: #selector(pausePressed(_:)), for: .touchDown) 

    durationLabel = UILabel() 
    durationLabel.textColor = UIColor.black 
    durationLabel.font = Util.getFontSize() 
    durationLabel.textAlignment = .center 
    durationLabel.text = "0:00" 

    stopButton = UIButton(type: .custom) 
    stopButton.titleLabel?.font = Util.getFontSize() 
    stopButton.setTitle("Stop", for: .normal) 
    stopButton.setTitleColor(UIColor.black, for: .normal) 
    stopButton.addTarget(self, action: #selector(stopPressed(_:)), for: .touchDown) 

    let stackView = UIStackView(frame: CGRect(x: 0, y:0 , width: backView.frame.width, height: 40)) 
    stackView.alignment = .fill 
    stackView.axis = .horizontal 
    stackView.distribution = .fillEqually 
    stackView.spacing = 5 
    stackView.addArrangedSubview(pauseButton) 
    stackView.addArrangedSubview(durationLabel) 
    stackView.addArrangedSubview(stopButton) 

    backView.addSubview(stackView) 

    if audioViewYposition == nil { 
     audioViewYposition = self.view.frame.height - 40 
    } 

    UIView.animate(withDuration: 0.2, delay: 0.1, options: .curveEaseInOut, animations: { 
     backView.frame.origin.y = self.audioViewYposition 
    }, completion: nil) 

Answer 1

上的错误表示您需要添加内容视图中的子视图，而不是直接对视觉效果视图，以便解决办法是：

backView.contentView.addSubview(stackView) 

确保，如果你的异常断点启用跳过从断点处几帧看到控制台中的错误消息：

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', 
reason: '<UIStackView: 0x109946ff0; frame = (0 0; 375 40); layer = <CATransformLayer: 0x1c4236640>> 
has been added as a subview to 
<UIVisualEffectView: 0x109945f40; frame = (0 702; 375 40); autoresize = W+H; tag = 123456; layer = <CALayer: 0x1c002ebc0>>. 
Do not add subviews directly to the visual effect view itself, 
instead add them to the -contentView.'