升级到Swift 3后，属性'self.delegate'未在super.init调用时初始化 [英] Property 'self.delegate' not initialized at super.init call after upgrading to Swift 3

问题描述

升级到Swift 3后，我现在收到此错误：

After upgrading to Swift 3 I now get this error:

属性'self.delegate'未在super.init调用时初始化

Property 'self.delegate' not initialized at super.init call

在NSObject类定义

On NSObject Class defined

open class NSObject : NSObjectProtocol {
   public init()  
}

IQKeyboardReturnKeyHandler class

IQKeyboardReturnKeyHandler class

public override init() {
   super.init()    //Error here
}

public init(controller : UIViewController) {
   super.init()    //Error here
   addResponderFromView(controller.view)
}

有关如何更正此问题的任何建议吗？

Any suggestions on how to correct this?

推荐答案

我假设你的类IQKeyboardReturnKeyHandler你有这样的声明：

I assume that in your class IQKeyboardReturnKeyHandler you have such declaration:

weak var delegate: YourDelegateProtocol

既然它既不是可选的也不是隐式展开的你ave在之前初始化调用超类的初始值设定项。

Since it's neither an optional nor an implicitly unwrapped you have to initialize it before calling the initializer of the superclass.

但是，使用委托模式，最好将您的委托属性声明为可选：

However, using the delegate pattern, it's better to declare your delegate property as an optional:

weak var delegate: YourDelegateProtocol?

在这种情况下，没有必要在调用超类的初始值设定项之前设置委托，所以你的代码将如下所示：

In this case it isn't necessary to set the delegate before calling the initializer of the superclass, so your code will look like this:

weak var delegate: YourDelegateProtocol?

public override init() {
    super.init()
    self.delegate = nil
}

public init(controller : UIViewController) {
    super.init()
    self.delegate = controller
    addResponderFromView(controller.view)
}

重要！使用委托模式时，始终将您的委托属性声明为弱避免参考周期。

Important! When using the delegate pattern, always declare your delegate property as weak to avoid reference cycles.

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