Swift：为什么我不能从override init调用方法？

概述我有以下代码示例(来自PlayGround)： class Serializable : NSObject{override init() { }}class Device : Serializable{ var uuid:String override init() { println("init ") self.uuid = "X 我有以下代码示例(来自PlayGround)：

class Serializable : NSObject{overrIDe init() { }}class Device : Serializable{    var uuID:String    overrIDe init() {        println("init ")        self.uuID = "XXX"       self.uuID = Device.createUUID()        println(self.uuID)    }   class func createUUID() -> String{       return "XXX2"    }}var device = Device()

@H_301_3@您可以注意到我将createUUID方法实现为静态.

@H_301_3@但是为什么我不能以静态的方式从init调用这个方法呢？ ：

class Serializable : NSObject{overrIDe init() { }}class Device : Serializable{    var uuID:String    overrIDe init() {        // trIEd        // super.init()        println("init ")        self.uuID = "XXX"       self.uuID = self.createUUID() //  ERROR       self.uuID = createUUID() // ERROR        println(self.uuID)        // trIEd        // super.init()    }  func createUUID() -> String{       return "XXX2"    }}var device = Device()

@H_301_3@没有继承它可以正常工作：

class Device {    var uuID:String     init() {        println("init ")        self.uuID = "XXX"       self.uuID = self.createUUID()        println(self.uuID)    }    func createUUID() -> String{       return "XXX2"    }}var device = Device()

有两个竞争 initialization safety checks导致您的问题.

Safety check 1 @H_301_3@A designated initializer must ensure that all of the propertIEs introduced by its class are initialized before it delegates up to a superclass initializer.

@H_301_3@和

Safety check 4 @H_301_3@An initializer cannot call any instance methods,read the values of any instance propertIEs,or refer to self as a value until after the first phase of initialization is complete.

@H_301_3@下面是它的工作原理.

overrIDe init() {    super.init() // Fails safety check 1: uuID is not initialized.    uuID = createUUID()}

@H_301_3@反过来,

overrIDe init() {    uuID = createUUID() // Fails safety check 4: cannot call an instance method before initialization is complete.    super.init()}

@H_301_3@感谢@Ruben in his answer

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