ios - 泄漏的监听器 firebase ios

Question

我正在尝试为聊天功能加载消息框数据。

消息框加载为:

override func viewDidAppear(animated: Bool) {
          super.viewDidAppear(animated)

if (PFUser.currentUser()!["firebaseUID"] !== nil)
{
    print(PFUser.currentUser()!["firebaseUID"])
   self.updateResultArray(PFUser.currentUser()!["firebaseUID"] as! String)
}
}

    func updateResultArray(uid: String) {


    let userName = String(PFUser.currentUser()!["username"])

    //print("updateResultArray is getting called")
    let userhandle = self.firebase.childByAppendingPath("users").childByAppendingPath(uid).childByAppendingPath("rooms").queryOrderedByValue()
        .observeSingleEventOfType(.Value, withBlock: { roomsnapshot in

            let enumerator = roomsnapshot.children
            while let rest = enumerator.nextObject() as? FDataSnapshot {
                self.roomArray.append(rest.key)
            }

            //get the latest message from all the rooms
            if self.roomArray.isEmpty == false
            {
                for i in 0...self.roomArray.count-1
                {
                    print("in the room loop \(self.roomArray[i])")

                    let messagehandle = self.messagesRef.childByAppendingPath(self.roomArray[i]).queryOrderedByKey().queryLimitedToFirst(1).observeSingleEventOfType(.Value, withBlock: {
                        messagesnapshot in

                        print("the messagesnapshot child count is \(messagesnapshot.childrenCount)")
                        let enumerator = messagesnapshot.children
                        while let rest = enumerator.nextObject() as? FDataSnapshot {

                            let sender = rest.value.objectForKey("sender") as? String
                            let reciever = rest.value.objectForKey("reciever") as? String

                            //print("sender is \(sender!) and reciever is \(reciever!)")


                            let eventhandle = self.firebase.childByAppendingPath("rooms").childByAppendingPath(self.roomArray[i]).observeSingleEventOfType(.Value, withBlock: { eventsnapshot in

                                if eventsnapshot.value is  NSNull {
                                    // The value is null
                                }
                                else
                                {
                                let eventAttr = eventsnapshot.value.objectForKey("eventAttributes") as? String
                                let eventDetails = eventsnapshot.value.objectForKey("eventDetails") as? String


                                //print("userName is \(userName)")
                                //print("sender is \(sender)")
                                if (userName !=  sender!) //for event joinee
                                {
                                    let firstname1 = eventsnapshot.value.objectForKey("firstname1") as? String
                                    self.otherNames.append(sender!)
                                    self.resultsNameArray.append(firstname1!)
                                    self.base4String = eventsnapshot.value.objectForKey("img1") as! String
                                    self.resultsImageFiles.append(self.base4String)

                                }
                                else //for event creator
                                {
                                    let firstname2 = eventsnapshot.value.objectForKey("firstname2") as? String
                                    self.otherNames.append(reciever!)
                                    self.resultsNameArray.append(firstname2!)
                                    self.base4String = eventsnapshot.value.objectForKey("img2") as! String
                                    self.resultsImageFiles.append(self.base4String)

                                }

                                let newlineChars = NSCharacterSet.newlineCharacterSet()
                                let evntArray = eventDetails!.componentsSeparatedByCharactersInSet(newlineChars).filter{!$0.isEmpty}
                                self.eventArray.append(evntArray[0])

                                self.eventdetailsArray.append(eventAttr!)

                                dispatch_async(dispatch_get_main_queue()) { () -> Void in
                                    self.resultsTable.reloadData()
                                }

                                }

                            })

                           // self.firebase.removeAuthEventObserverWithHandle(eventhandle)
                        }

                    })

                    //self.messagesRef.removeAuthEventObserverWithHandle(messagehandle)
                }

            }
        })


      //firebase.removeAuthEventObserverWithHandle(userhandle)


}

因为我使用的是 observeSingleEventOfType，所以我没有编写代码来删除处理程序(我也尝试过)。

在个人聊天中，代码是这样的:

func refreshResults() {

    print("the roomid is \(roomid)")

    //update from firebase
   let messagehandle = self.messagesRef.childByAppendingPath(roomid).queryOrderedByKey()
        .observeEventType(.Value, withBlock: { messageTextsnapshot in

            self.messageArray.removeAll()
            self.senderArray.removeAll()


            //                print("the messageTextsnapshot child count is \(messageTextsnapshot.childrenCount)") // I got the expected number of items
            let enumerator = messageTextsnapshot.children
            while let rest = enumerator.nextObject() as? FDataSnapshot {


                let text = rest.value.objectForKey("message") as? String
                let sender = rest.value.objectForKey("sender") as? String


                if text != nil && text != ""
                {

                    self.messageArray.append(text!)
                    self.senderArray.append(sender!)

                }

            }


            for subView in self.resultsScrollView.subviews {
                subView.removeFromSuperview()
            }

            for var i = 0; i <= self.messageArray.count-1; i++ {


                if self.senderArray[i] == userName {


                    if (self.messageArray[i].rangeOfString(self.acceptMessage) != nil)
                    {

                        let chatBubbleData = ChatBubbleData(text: self.messageArray[i], image:self.myImg, date: NSDate(), type: .AcceptMine)

                        self.addChatBubble(chatBubbleData)

                    }
                    else
                    {

                        let chatBubbleData = ChatBubbleData(text: self.messageArray[i], image:self.myImg, date: NSDate(), type: .Mine)

                        self.addChatBubble(chatBubbleData)

                    }

                } else {

                    if (self.messageArray[i].rangeOfString(self.acceptMessage) != nil)
                    {

                        let chatBubbleData = ChatBubbleData(text: self.messageArray[i], image:self.otherImg, date: NSDate(), type: .Accept)

                        self.addChatBubble(chatBubbleData)

                    }
                    else
                    {

                        let chatBubbleData = ChatBubbleData(text: self.messageArray[i], image:self.otherImg, date: NSDate(), type: .Opponent)

                        self.addChatBubble(chatBubbleData)
                    }
                }

                let bottomOffset:CGPoint = CGPointMake(0, self.resultsScrollView.contentSize.height - self.resultsScrollView.bounds.size.height)
                self.resultsScrollView.setContentOffset(bottomOffset, animated: false)

            }


        })

    self.messagesRef.removeAuthEventObserverWithHandle(messagehandle)
}

还有一些其他类似的监听器。问题是当我从这个 View 返回时(个人聊天到消息框，内存消耗增加。我已经清除了所有数组并在使用后立即关闭了处理程序。但内存消耗仍然增加，有时在消息框中再次复制相同的行.我应该怎么解决这个问题。我试过使用observeSingleEventOfType 但它不是正确的解决方案，因为数据同步停止。

以此为引用: https://www.firebase.com/blog/2015-10-15-best-practices-uiviewcontroller-ios-firebase.html

Answer 1

由于持有对消息框对象的引用的监听器回调 block 引起的保留周期，您的消息框对象似乎未被释放。您可以通过在传递给其他对象的 block 中使用 [weak self] 来缓解这种情况。例如:

            .observeSingleEventOfType(.Value, withBlock: 
                {
                    [weak self] roomsnapshot in

                    let enumerator = roomsnapshot.children
                    ...

这使得“self”成为可选类型，然后您可以添加:

guard let strongSelf = self else { ... }