无法使用 Xib 将 UIView 类型的值转换为 [CustomView] [英] Could not cast value of type UIView to [CustomView] using Xib

问题描述

我看过很多类似的问题，但很多都不是最新的，而且没有一个能解决我的问题.

I've seen a number of similar questions, but many aren't up-to-date, and none have fixed my issue.

我有一个自定义的 Xib 和类，CardView.当我尝试在代码中实例化它时，我得到 Could not cast value of type 'UIView' to 'CardView'.

I have a custom Xib and class, CardView. When I try to instantiate it in code, I get Could not cast value of type 'UIView' to 'CardView'.

类如下:

class CardView: NibView {

    @IBOutlet var contentView: UIView!
    @IBOutlet weak var wordLabel: UILabel!
    @IBOutlet weak var flipButton: UIButton!
    @IBOutlet weak var playButton: UIButton!

    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonInit()
    }

    private func commonInit() {
        Bundle.main.loadNibNamed("CardView", owner: self, options: nil)
        addSubview(contentView)
        contentView.frame = self.bounds
        contentView.autoresizingMask = [.flexibleHeight, .flexibleWidth]

    }

    override func awakeFromNib() {
        super.awakeFromNib()
    }
}

和 NibView 是一个自定义超类，看起来像:

and NibView is a custom superclass and looks like:

class NibView: UIView {
    var view: UIView!
    override init(frame: CGRect) {
        super.init(frame: frame)

        // Setup view from .xib file
        xibSetup()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        // Setup view from .xib file
        xibSetup()
    }
}
private extension NibView {

    func xibSetup() {
        backgroundColor = UIColor.white
        view = loadNib()
        // use bounds not frame or it'll be offset
        view.frame = bounds
        // Adding custom subview on top of our view
        addSubview(view)

        view.translatesAutoresizingMaskIntoConstraints = false
        addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|[childView]|",
                                                      options: [],
                                                      metrics: nil,
                                                      views: ["childView": view]))
        addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[childView]|",
                                                      options: [],
                                                      metrics: nil,
                                                      views: ["childView": view]))
    }
}

extension UIView {
    /** Loads instance from nib with the same name. */
    func loadNib() -> UIView {
        let bundle = Bundle(for: type(of: self))
        let nibName = type(of: self).description().components(separatedBy: ".").last!
        let nib = UINib(nibName: nibName, bundle: bundle)
        return nib.instantiate(withOwner: self, options: nil).first as! UIView
    }
}

这是我的文件检查器的屏幕截图，显示我将 File's Owner 自定义类设置为 CardView，这似乎是许多人的绊脚石

Here is a screenshot of my file inspector showing that I set the File's Owner custom class to CardView, which seems to be a stumbling block for many

最后，我尝试实例化 CardView 如下: CardView().loadNib() as!CardView

Finally, I try to instantiate the CardView as follows: CardView().loadNib() as! CardView

推荐答案

如果有人仍然有这个问题，我也有同样的问题，我想我们遵循相同的教程.

In case someone still having this problem, I have the same problem and I think we follow same tutorial.

您在 xibSetup() 中调用了 loadNib().我想你不必再打电话了.

You have called loadNib() in your xibSetup(). I think you don't have to call it again.

所以而不是使用

let myCardView = CardView().loadNib() as! CardView

我只是用

let myCardView = CardView()

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