在swift中覆盖UIView的init方法 [英] Override init method of UIView in swift

问题描述

class CustomView: UIView {

    var subViewColor:UIColor
    var subViewMessage:String

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

    init(subViewColor:UIColor,subViewMessage:String){

        self.subViewColor = subViewColor
        self.subViewMessage = subViewMessage
        super.init()

    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}

我有一个类，我希望用户通过提供以下属性来初始化自定义视图：

I have a class where I want the user to initialize a custom view either by giving properties like:

let myView = CustomLoadingView(initialize properties here)

如果用户不想初始化自己的属性，我想使用默认属性初始化 CustomLoadingView ...

If the user does not want to initialize their own properties, I want to initialize CustomLoadingView using default properties...

let myView = CustomLoadingView() // this should initialize using default value

然而，有了这个，我收到此错误：

However, with this, I am getting this error:

必须调用超类UIView的指定初始化器

Must call a designated intializer of the superclass UIView

推荐答案

在 init（subviewColor：UIColor，subViewMessage：String）中，您没有调用指定的初始值设定项（如编译器很好地指出。）

In init(subviewColor: UIColor, subViewMessage: String), you aren't calling the designated initializer (as the compiler points out nicely).

如果您不知道指定的初始值设定项是什么，它们是具有的初始化程序，由某个时候的子类。来自文档：

If you don't know what designated initializers are, they are initializers that have to be called by the subclass at some point. From the docs:

指定的初始值设定项是类的主要初始值设定项。指定的初始化程序完全初始化该类引入的所有属性，并调用适当的超类初始化程序以继续超类链的初始化过程。

Designated initializers are the primary initializers for a class. A designated initializer fully initializes all properties introduced by that class and calls an appropriate superclass initializer to continue the initialization process up the superclass chain.

在这种情况下， UIView 的指定初始化程序是 init（frame：CGRect），这意味着在某些时候，你的新初始值设定项 init（subviewColor：UIColor，subViewMessage：String 必须调用 super.init（frame :) 。

In this case, the designated initializer for UIView is init(frame: CGRect), meaning at some point, your new initializer init(subviewColor: UIColor, subViewMessage: String must call super.init(frame:).

为了解决这个问题，请进行以下更改：

In order to fix this, make the following changes:

init(frame: CGRect, subViewColor: UIColor, subViewMessage: String){

    self.subViewColor = subViewColor
    self.subViewMessage = subViewMessage
    super.init(frame: frame)

}

或者您可以在班级中调用其他初始化程序，最终调用指定的初始化程序。

OR you can call your other initializer in your class which ends up calling the designated initializer.

override init(frame: CGRect) {
    super.init(frame: frame) // calls designated initializer
}

convenience init(frame: CGRect, subViewColor: UIColor, subViewMessage: String){

    self.subViewColor = subViewColor
    self.subViewMessage = subViewMessage
    self.init(frame: frame) // calls the initializer above

}

对于只需 CustomLoadingView（）的便捷方法，你必须为此添加另一个初始值设定项。将此代码添加到自定义视图中：

As for the convenience method with simply CustomLoadingView(), you have to add another initializer for that. Add this code to your custom view:

convenience init() {
    self.init(frame: DEFAULT_FRAME, subViewColor: DEFAULT_COLOR, subViewMessage: DEFAULT_MESSAGE)
}

如果您想了解更多有关指定和方便初始化者，阅读它们此处和此处 。

If you want to learn more about designated and convenience initializers, read about them here and here.

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