Firebase實時陣列計數不匹配

Question

我有一個使用Firebase實時數據庫的iOS快速應用程序。如果我通常到目前爲止使用該應用程序，我找不到任何問題。但是，我想預測邊緣情況。

我試圖在我推送更新之前測試我的應用程序，而且我正在做的一種方式是快速地從具有tableView的VC到來到VC，這是一個詳細的VC。如果我做了幾次，最終tableview會顯示大量重複的數據。

我已經通過在我的模擬器上打開tableview並進入我的Firebase控制檯並手動更改值並在設備上即時更改字符串來測試了我的應用程序。

所以我很困惑，爲什麼我的tableview會顯示不正確的孩子數量，如果它不斷檢查值應該是什麼。

// MARK: Firebase Methods 

func checkIfDataExits() { 
    DispatchQueue.main.async { 
     self.cardArray.removeAll() 
     self.ref.observe(DataEventType.value, with: { (snapshot) in 
      if snapshot.hasChild("cards") { 
       self.pullAllUsersCards() 
      } else { 
       self.tableView.reloadData() 
      } 
     }) 
    } 
} 



func pullAllUsersCards() { 
    cardArray.removeAll() 
    let userRef = ref.child("users").child((user?.uid)!).child("cards") 
    userRef.observe(DataEventType.value, with: { (snapshot) in 
     for userscard in snapshot.children { 
      let cardID = (userscard as AnyObject).key as String 
      let cardRef = self.ref.child("cards").child(cardID) 
      cardRef.observe(DataEventType.value, with: { (cardSnapShot) in 
       let cardSnap = cardSnapShot as DataSnapshot 
       let cardDict = cardSnap.value as! [String: AnyObject] 
       let cardNickname = cardDict["nickname"] 
       let cardType = cardDict["type"] 
       let cardStatus = cardDict["cardStatus"] 
       self.cardNicknameToTransfer = cardNickname as! String 
       self.cardtypeToTransfer = cardType as! String 
       let aCard = CardClass() 
       aCard.cardID = cardID 
       aCard.nickname = cardNickname as! String 
       aCard.type = cardType as! String 
       aCard.cStatus = cardStatus as! Bool 
       self.cardArray.append(aCard) 
       DispatchQueue.main.async { 
        self.tableView.reloadData() 
       } 
      }) 
     } 
    }) 
} 

Answer 1

我得到的幫助和改變了我的代碼厲害，所以現在它的工作原理

func checkIfDataExits() { 
    self.ref.observe(DataEventType.value, with: { (snapshot) in 
     if snapshot.hasChild("services") { 
      self.pullCardData() 
     } else { 
      DispatchQueue.main.async { 
       self.collectionView.reloadData() 
      } 
     } 
    }) 
} 


func pullCardData() { 
    let cardRef = self.ref.child("cards") 
    cardRef.observe(DataEventType.value, with: { (snapshot) in 
     for cards in snapshot.children { 
      let allCardIDs = (cards as AnyObject).key as String 
      if allCardIDs == self.cardID { 
       if let childId = self.cardID { 
        let thisCardLocation = cardRef.child(childId) 
        thisCardLocation.observe(DataEventType.value, with: { (snapshot) in 
         let thisCardDetails = snapshot as DataSnapshot 
         if let cardDict = thisCardDetails.value as? [String: AnyObject] { 
          self.selectedCard?.cardID = thisCardDetails.key 
          self.selectedCard?.nickname = cardDict["nickname"] as? String ?? "" 
          self.selectedCard?.type = cardDict["type"] as? String ?? "" 
          self.pullServicesForCard() 
         } 
        }) 
       } 
      } 
     } 
    }) 
} 

func pullServicesForCard() { 
    if let theId = self.cardID { 
     let thisCardServices = self.ref.child("cards").child(theId).child("services") 
     thisCardServices.observe(DataEventType.value, with: { (serviceSnap) in 
      if self.serviceArray.count != Int(serviceSnap.childrenCount) { 
       self.serviceArray.removeAll() 
       self.fetchAndAddAllServices(serviceSnap: serviceSnap, index: 0, completion: { (success) in 
        if success { 
         DispatchQueue.main.async { 
          self.collectionView.reloadData() 
         } 
        } 
       }) 
      } 
     }) 
    } 
} 

func fetchAndAddAllServices(serviceSnap: DataSnapshot, index: Int, completion: @escaping (_ success: Bool) -> Void) { 
    if serviceSnap.hasChildren() { 
     if index < serviceSnap.children.allObjects.count { 
      let serviceChild = serviceSnap.children.allObjects[index] 
      let serviceID = (serviceChild as AnyObject).key as String 

      let thisServiceLocationInServiceNode = self.ref.child("services").child(serviceID) 

      thisServiceLocationInServiceNode.observeSingleEvent(of: DataEventType.value, with: { (thisSnap) in 
       let serv = thisSnap as DataSnapshot 

       if let serviceDict = serv.value as? [String: AnyObject] { 

        let aService = ServiceClass(serviceDict: serviceDict) 
        self.serviceCurrent = serviceDict["serviceStatus"] as? Bool 
        self.serviceName = serviceDict["serviceName"] as? String ?? "" 
        self.serviceURL = serviceDict["serviceURL"] as? String ?? "" 
        self.serviceFixedBool = serviceDict["serviceFixed"] as? Bool 
        self.serviceFixedAmount = serviceDict["serviceAmount"] as? String ?? "" 
        self.attentionInt = serviceDict["attentionInt"] as? Int 

        self.totalArr.append((serviceDict["serviceAmount"] as? String)!) 
        //      self.doubleArray = self.totalArr.flatMap{ Double($0) } 
        //      let arraySum = self.doubleArray.reduce(0, +) 
        //      self.title = self.selectedCard?.nickname ?? "" 

        //      if let titleName = self.selectedCard?.nickname { 
        //       self.title = "\(titleName): \(arraySum)" 
        //      } 

        aService.serviceID = serviceID 
        if serviceDict["serviceStatus"] as? Bool == true { 
         self.selectedCard?.cStatus = true 
        } else { 
         self.selectedCard?.cStatus = false 
        } 



        if !self.serviceArray.contains(where: { (service) -> Bool in 
         return service.serviceID == aService.serviceID 
        }) { 
         self.serviceArray.append(aService) 

         self.serviceArray.sort {$1.serviceAttention < $0.serviceAttention} 

        } 
       } 
       self.fetchAndAddAllServices(serviceSnap: serviceSnap, index: index + 1, completion: completion) 
      }) 

     } 
     else { 
      completion(true) 
     } 
    } 
    else { 
     completion(false) 
    } 

}