Swift：幫助發現導致我的應用程序崩潰的不一致性

Question

當我運行我的應用程序時，我得到了臭名昭着的錯誤：unexpectedly found nil while unwrapping an Optional value。我相信這是由於我的代碼不一致，我似乎無法找到...

問題出現在4個地方中的任何一個。我的子類對象CustomMessage.swift，功能addMessage，didPressSendButton或observeMessages

這裏是我的子類的對象CustomMessage：

class CustomMessage: JSQMessage { 
    var score : Int 

    init(senderId: String, displayName: String, text: String, date: NSDate, score: Int) { 
     self.score = score 
     // super.init(senderId:senderId, displayName:displayName, text:text) // Must call a designated initializer of the superclass 'JSQMessage' 
     //super.init(senderId: senderId, displayName: displayName, text: text) 
     super.init(senderId: senderId, senderDisplayName: displayName, date: date, text: text) 
    } 

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

這裏是我已經提到的其他三個功能。請注意，所有這些一起工作。

func addMessage(id: String, text: String, displayName: String, date: NSDate, score: Int) { 

     // Make sure the character count is between 10 and 140, then add message to message list to display 
     if (text.characters.count <= 10 || text.characters.count >= 140) { 

     } 
     else { 
      // let message = JSQMessage(senderId: id, displayName: displayName, text: text) 
      let message = CustomMessage(senderId: id, displayName: displayName, text: text, date: date, score: score) 
      messages.append(message) 
     } 

    } 

    override func didPressSendButton(button: UIButton!, withMessageText text: String!, senderId: String!, 
          senderDisplayName: String!, date: NSDate!) { 

     // Make sure the character count is between 10 and 140, then save data to Firebase 
     if (text.characters.count <= 10 || text.characters.count >= 140) { 
      print("Your text must be between 10 and 140 characters") 
     } 
     else { 
      let itemRef = messageRef.childByAutoId() // 1 
      let messageItem = [ // 2 
       "text": text, 
       "senderId": senderId, 
       "location": getLocation(), 
       "date": String(date), 
       "score": getScore() 
      ] 
      itemRef.setValue(messageItem) // 3 

      // 4 
      JSQSystemSoundPlayer.jsq_playMessageSentSound() 

      // 5 

      finishSendingMessage() 

      Answers.logCustomEventWithName("Message sent", customAttributes: nil) 
     } 

    } 

    private func observeMessages() { 

     print("gets here") 

     // 1 
     let messagesQuery = messageRef.queryLimitedToLast(25) 
     // 2 
     messagesQuery.observeEventType(.ChildAdded) { (snapshot: FIRDataSnapshot!) in 
      // 3 
      print("gets inside") 

      let id = snapshot.value!["senderId"] as! String 
      let text = snapshot.value!["text"] as! String 
      let locationId = snapshot.value!["location"] as! String 
      let textScore = snapshot.value!["score"] as! NSInteger 
      let date = NSDate() 

      // 4 
      self.addMessage(id, text: text, displayName: locationId, date: date, score: textScore) 

      print("finished adding messages") 

      // 5 
      self.finishReceivingMessage() 

      Answers.logCustomEventWithName("Visited RoastChat", customAttributes: nil) 

     } 
    } 

我也試圖做一些調試和代碼不會崩潰，直到observeMessages（）被調用，但即使如此，它運行（注意方法中我打印語句），但不會崩潰，直至線：

self.addMessage(id, text: text, displayName: locationId, date: date, score: textScore)

這使我相信，這個問題是由於不一致的地方這三個函數裏面。我無法弄清楚它在哪裏或是什麼。

感謝您的幫助！

讓我知道你是否需要任何額外的信息。

Answer 1

我推翻了這麼多......在之前的測試中，我保存了沒有我的新屬性的對象，所以當應用程序試圖調用舊數據的新屬性時，Xcode會迴應此錯誤消息。對我而言，這是愚蠢的。