ios - 让@IBDesignable UIView 在不崩溃 Interface Builder 的情况下进行绘制

Question

我正在尝试在界面生成器中配置自定义 UIView 并获取要呈现的 View 。每次我尝试使用自定义 Xib 执行此操作时，我都可以让 xib 在界面生成器中看起来很好，但是当我尝试将我的 MyCustomView 放入 UIVewController 时在界面生成器中，我遇到了各种编译器错误。

我看过的每个教程都是这样的:“只需在你的类声明前面添加 @IBDesignable 并将 @IBInspectable 放在你的变量前面，然后然后观看魔法发生”(例如:WWDC 2015 video)。或者它是在 Objective-C 中，或者它是一个 30 分钟的带有中文字幕的阿拉姆语视频等。

我的最终目标是能够拖入一个 UIView，在身份检查器中分配我的自定义类，并让 xib 的内容填充我拖入的 UIView 并能够调整 @IBInspectable 属性.

我在哪里寻找答案:

SO Post: @IBDesignable crashing agent

NS Hipster

A Medium Post

我遇到的错误:

Base.lproj/Main.storyboard: error: IB Designables: Failed to render and update auto layout status for PlaylistViewController (o1G-QR-OwX): The agent crashed

Base.lproj/Main.storyboard: error: IB Designables: Failed to update auto layout status: The agent crashed

我的 CurrentlyPlayingView 的身份检查器:

出现上述错误后我的观点的 Storyboard:

我想要出现在上述 Storyboard底部的 View :

我的代码:

import UIKit

@IBDesignable class CurrentlyPlayingView: UIView {

    var view = UIView()

    @IBOutlet weak var titleLabel: UILabel!
    @IBOutlet weak var subtitleLabel: UILabel!
    @IBOutlet weak var progressSlider: UISlider!

    // IBInspectable attributes

    @IBInspectable public var titleLabelColor: UIColor = .black {
        didSet {
            self.titleLabel.textColor = titleLabelColor
        }
    }

    @IBInspectable public var subtitleLabelColor: UIColor = .black {
        didSet {
            self.subtitleLabel.textColor = subtitleLabelColor
        }
    }

    @IBInspectable public var sliderMinColor: UIColor = .blue {
        didSet {
            self.progressSlider.minimumTrackTintColor = sliderMinColor
        }
    }

    @IBInspectable public var sliderMaxColor: UIColor = .red {
        didSet {
            self.progressSlider.maximumTrackTintColor = sliderMaxColor
        }
    }

    // MARK: - Initialization

    override init(frame: CGRect) {
        super.init(frame: frame)
        xibSetup()
        initialConfig()
    }

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

    private func initialConfig() {
        self.titleLabel.textColor = titleLabelColor
        self.subtitleLabel.textColor = subtitleLabelColor
        self.progressSlider.minimumTrackTintColor = sliderMinColor
        self.progressSlider.maximumTrackTintColor = sliderMaxColor
    }

    // MARK: - Nib handlers

    private func xibSetup() {
        view = loadViewFromNib()
        view.frame = bounds

        // Make the view stretch with containing view
        view.autoresizingMask = [UIViewAutoresizing.flexibleWidth, UIViewAutoresizing.flexibleHeight]

        // Adding custom subview on top of our view (over any custom drawing > see note below)
        addSubview(view)
    }

    private func loadViewFromNib() -> UIView {
        let bundle = Bundle(for: type(of: self))
        let nib = UINib(nibName: "CurrentlyPlayingView", bundle: bundle)

        // Assumes UIView is top level and only object in CustomView.xib file
        let view = nib.instantiate(withOwner: self, options: nil).first as! UIView
        return view
    }
}

如果您已经读到这里，感谢您的阅读。如果你看到我遗漏了什么，我欢迎你的建议。

Answer 1

我认为这是因为您缺少 prepareForInterfaceBuilder 函数。

像这样重写这个函数。

override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        //setup your view with the settings
    }

OP 的附录:

将 UIView 拖出到 YourViewController 并将其在 Identity Inspector 中的自定义类设置为 YourCustomView 后，确保“Inherit from Target”是勾选(从 Xcode 8.x 开始)。