override init() {
    super.init();
}

init(title:String?) {
    super.init();
    self.title = title
}

convenience init(title:String?,imageName:String?) {
    self.init(title:title)
    self.imageName = imageName
}

convenience init(title:String?,imageName:String?,contentKey:String?) {
    self.init(title:title,imageName:imageName)
    self.contentKey = contentKey
}

我将样品插入操场,以下是我如何使用它：

class Y { }
class X : Y {
    var title: String?
    var imageName: String?

    override init() {

    }

    init(aTitle:String?) {
        super.init()
        self.title = aTitle
    }

    convenience init(aTitle:String?,aImageName:String?) {
        self.init(aTitle: aTitle)
        self.imageName = aImageName
    }
}

@H_502_2@> init(aTitle：String？,aImageName：String？)无法调用init(aTitle :)并仍然是指定的初始化程序,它必须是一个便利初始化程序.
> self.init必须在init之前的任何其他内容(aTitle：String？,aImageName：String？).
>初始化程序必须传递参数名称self.init(aTitle)必须是self.init(aTitle：aTitle).

@H_502_2@作为旁注,我删除了不需要的分号,并首先将super.init()用于样式原因.

@H_502_2@希望有所帮助.

@H_502_2@UPDATE

@H_502_2@要遵循Apple的建议,应该只指定一个,其余应该是便利初始化器.例如,如果您决定init(aTitle：String？)应该是指定的初始化程序,那么代码应如下所示：

convenience override init() {
    self.init(aTitle: nil) // A convenience initializer calls the designated initializer.
}

init(aTitle:String?) {
    super.init() // Only the designated initializer calls super.init.
    self.title = aTitle
}

convenience init(aTitle:String?,aImageName:String?) {
    self.init(aTitle: aTitle)  // A convenience initializer calls the designated initializer.
    self.imageName = aImageName
}

@H_502_2@有时您可能需要多次指定的初始化程序,例如UIView,但这应该是一个例外,而不是规则.

@H_502_2@更新2

@H_502_2@类应该有一个指定的初始化程序.便利初始化程序将(最终)调用指定的初始化程序.

@H_502_2@Initialization

@H_502_2@A class may have multiple initializers. This occurs when the initialization data can take varied forms or where certain initializers,as a matter of convenience,supply default values. In this case,one of the initialization methods is called the designated initializer,which takes the full complement of initialization parameters.

@H_502_2@Multiple initializers

The Designated Initializer

@H_502_2@The initializer of a class that takes the full complement of initialization parameters is usually the designated initializer. The designated initializer of a subclass must invoke the designated initializer of its superclass by sending a message to super. The convenience (or secondary) initializers—which can include init—do not call super. Instead they call (through a message to self) the initializer in the series with the next most parameters,supplying a default value for the parameter not passed into it. The final initializer in this series is the designated initializer.