Question

我有以下类符合协议SentenceDelegate

class SentenceMarkov : SentenceDelegate{

  var UltimateSentence : Sentence {
    didSet { UltimateSentence.sentenceDelegate = self}
  }
  var PenultimateSentence : Sentence 

  init(Ult : Sentence, Penult : Sentence){
    self.UltimateSentence = Ult
    self.PenultimateSentence = Penult
  }


  func startChain(){
    self.PenultimateSentence.sentenceDelegate = self
    self.PenultimateSentence.start()
  }

  func sentenceDidFinish(){
    self.nextSentence(self.UltimateSentence.type, penUltType:  self.PenultimateSentence.type)
  }

  //etc.
}

我将SentenceDelegate定义如下：

protocol SentenceDelegate: class{
  func sentenceDidFinish()
 }

最后，我的Delegator类Sentence定义如下：

class Sentence : NSObject {
  var type=""
  var eventArray:[SoundEvent] = []


  weak var sentenceDelegate: SentenceDelegate? 

  weak var soundEventDelegate: SoundEventDelegate? = nil {
    didSet {
        eventArray.forEach() {$0.delegate = soundEventDelegate}
    }
  }

  init(type :String){
   //etc.
  }


  func sentenceDone(){
    sentenceDelegate?.sentenceDidFinish() //This is where the program breaks
  }

  func start(){
    self.playEvent(0)
  }

  func handleTimer(timer: NSTimer) {
    guard let index = timer.userInfo as? Int else { return }
    playEvent(index)
  }

  func playEvent(eventIndex : Int){
    if (eventIndex < 2){
        let currEvent = self.eventArray[eventIndex]
        currEvent.startEvent()
        let nextIndex = eventIndex + 1
        SharingManager.sharedInstance.globalTimer = NSTimer.scheduledTimerWithTimeInterval(currEvent.duration, target: self, selector: Selector("handleTimer:"), userInfo: NSNumber(integer: nextIndex), repeats: false)
    }
    else if (eventIndex==2){
        let currEvent = self.eventArray[eventIndex]
        currEvent.startEvent()
        SharingManager.sharedInstance.globalTimer = NSTimer.scheduledTimerWithTimeInterval(currEvent.duration, target: self, selector: Selector("sentenceDone"), userInfo: nil, repeats: false)
    }
    else{
        //Nothing
    }
  }
}

我将上述内容初始化为类，并以下列方式从ViewController启动程序：

    let s1:Sentence = Sentence(type: "S3")
    let s2:Sentence = Sentence(type: "S1")
    var newModel = SentenceMarkov(Ult: s1, Penult: s2)
    newModel.startChain()

当我运行程序时，它不会在Delegate类上执行SentenceDelegate方法sentenceDidFinish。当我为该方法设置断点时，程序永远不会停止。当我在Delegator类的sentenceDone上设置断点时，我检查self变量，看到sentenceDelegate已定义，但指向Delegator类的两个副本（{{1} }和UltimateSentence）而不是Delegate类。此外，在使用断点检查时，Delegator类的这两个实例具有PenultimateSentence属性sentenceDelegate。

与照片商量：

我不明白nil属性Sentence（他在 SentenceMarkov 中设置为sentenceDelegate）如何指向一个句子，而不是如何调用self {1}}。任何阐明我在推理/编程中的错误都将非常感激。

Answer 1

问题是您将didSet与init结合使用。在init期间不会调用这些方法，因此您需要创建一个特定的方法，并在init内调用它。例如;

var UltimateSentence : Sentence {
  didSet { setDelegate() }
}

func setDelegate() {
  UltimateSentence.sentenceDelegate = self
}

init(Ult : Sentence, Penult : Sentence){
  self.UltimateSentence = Ult
  self.PenultimateSentence = Penult
  setDelegate()
}

您也只是对代表保持弱引用。我不清楚有什么强烈的参考。如果没有任何强大的参考，它们将在超出范围时被销毁。您可以通过在print deinit内加SentenceMarkov来确认这一点。值得注意的是，Swift标准适用于以大写字母开头的类和以小写字母开头的实例。当你的实例以大写字母开头时，它使得习惯这个惯例的人更难阅读。

Delgator的委托属性指向两个Delegator而不是Delegate类

1 个答案: