Firebase dispatch_async 不断崩溃-swift 2 iOS9

Question

我正在使用 tabBar 控制器。 TabOne 是 rootVC。在 TabOne 中，我有一个 viewController，它通过 sendButton 向 Firebase 发送信息并以编程方式呈现 TabTwo。

在 TabTwo 中，我有获取信息并显示它的 tableView 控制器。奇怪的是，我运行了两次代码，一切都很好，我按下了发送按钮，出现了 TabTwo，它的表格视图正确地加载了具有正确信息的单元格。现在的问题是由于某种奇怪的原因，它只成功运行了这 2 次，并且从那时起它一直在 dispatch_async 上崩溃。

现在我只是尝试运行模拟器，而不是在 TabOne 中按下 sendButton，而是按下 TabTwo 的选项卡，应用程序在 dispatch_async 上崩溃。我没有尝试向 Firebase 发送任何内容，我只是单击了 TabTwo 的选项卡，并且 dispatch_async 因代码而崩溃：

Thread1: EXC_BAD_INSTRUCTION (code=EXC_1338_INVOP, subcode=0x0)

知道为什么我切换标签时它似乎崩溃了吗？ 知道为什么一切正常运行两次然后突然崩溃吗？

代码如下：

模型对象

class CookieModel: NSObject{
     var name: String?
}

标签1

class TabOneController: UIViewController{

var dbRef: FIRDatabaseReference!
let userID: String? = (FIRAuth.auth()?.currentUser?.uid)!
let cookieModel = [CookieModel]()

override func viewDidLoad() {
     super.viewDidLoad()
     self.dbRef = FIRDatabase.database().reference()
}

@IBAction func sendButton(sender: UIButton){
     self.sendToFireBase()

     let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
     let tabBarController = mainStoryboard.instantiateInitialViewController() as! UITabBarController
     tabBarController.selectedIndex = 1
     self.presentViewController(tabBarController , animated: true, completion: nil)
}

//Code to send data to FirebaseDatabase
func sendToFireBase(){

     let uniquePath = NSUUID().UUIDString
     let usersIDRef = self.dbRef.child("users").child(self.userID!)
     let cookiePath = usersIDRef.child("cookieData").child(self.uniquePath)

     let cookie0 = CookieModel()
     cookie0.name = "oatmeal"
     self.cookieModel.append(cookie0)

     let cookie1 = CookieModel()
     cookie1.name = "chocolate"
     self.cookieModel.append(cookie1)

     let cookie2 = CookieModel()
     cookie2.name = "coconut"
     self.cookieModel.append(cookie2)

     var cookieDict = [String:AnyObject]()
     cookieDict.updateValue(cookie0.name!, forKey: "cookie0")
     cookieDict.updateValue(cookie1.name!, forKey: "cookie1")
     cookieDict.updateValue(cookie2.name!, forKey: "cookie2")

     cookiePath.updateChildValues(cookieDict, withCompletionBlock: {
                (error, user) in

            if error != nil{
                print((error?.localizedDescription))
                return
            }
      }

}

tab2

class TabTwoController: UIViewController, UITableViewDataSource, UITableViewDelegate{

@IBOutlet weak var tableView: UITableView!

var dbRef: FIRDatabaseReference!
let userID: String? = (FIRAuth.auth()?.currentUser?.uid)!
var cookieModel = [CookieModel]()

override func viewDidLoad() {
        super.viewDidLoad()

     self.dbRef = FIRDatabase.database().reference()
     self.tableView.delegate = self

     self.observeFBCookieData()
}

//Code to retrieve data from FirebaseDatabase
func observeFBCookieData(){

    let usersIDRef = self.dbRef.child("users").child(self.userID!)
    let cookiePath = usersIDRef.child("cookieData")

    cookiePath.observeEventType(.ChildAdded, withBlock: {

        (snapshot) in

        if let dict = snapshot.value as? [String:AnyObject]{

        let cookie0 = dict["cookie0"] as? String
        let cookie1 = dict["cookie1"] as? String
        let cookie2 = dict["cookie2"] as? String

        let cookie0 = CookieModel()
        cookie0.name = cookie0!
        self.cookieModel.append(cookie0)

        let cookie1 = CookieModel()
        cookie1.name = cookie1!
        self.cookieModel.append(cookie1)

        let cookie2 = CookieModel()
        cookie2.name = cookie2!
        self.cookieModel.append(cookie2)

        dispatch_async(dispatch_get_main_queue(), {
                    self.tableView.reloadData()
                })
     }
  }, withCancelBlock: nil)
}

//MARK: -TableViewDatasource Methods
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return self.cookieModel.count
}



func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! MyCookieCell

        cell.titleLabel.text = self.cookieModel[IndexPath.row].name!

        return cell

    }

 } 

Answer 1

设置委托后，尝试在 viewDidLoad 中设置表视图的数据源。

Self.tableView.datasource = self