ios - 无法调用非函数类型的值 'Any?!' :- Firebase, Swift3

Question

这是我在迁移到 Swift 3 之前的代码:

ref.observeEventType(.ChildAdded, withBlock: { snapshot in
            let currentData = snapshot.value!.objectForKey("Dogs")
            if currentData != nil {
            let mylat = (currentData!["latitude"])! as! [String]
            let mylat2 = Double((mylat[0]))
            let mylon = (currentData!["longitude"])! as! [String]
            let mylon2 = Double((mylon[0]))
            let userid = (currentData!["User"])! as! [String]
            let userid2 = userid[0]
            let otherloc = CLLocation(latitude: mylat2!, longitude: mylon2!)
            self.distanceBetweenTwoLocations(self.currentLocation, destination: otherloc, userid: userid2)
            }
        })

这是我迁移到 Swift 3 后的代码:

ref.observe(.childAdded, with: { snapshot in
            let currentData = (snapshot.value! as AnyObject).object("Dogs")
            if currentData != nil {
                let mylat = (currentData!["latitude"])! as! [String]
                let mylat2 = Double((mylat[0]))
                let mylon = (currentData!["longitude"])! as! [String]
                let mylon2 = Double((mylon[0]))
                let userid = (currentData!["User"])! as! [String]
                let userid2 = userid[0]
                let otherloc = CLLocation(latitude: mylat2!, longitude: mylon2!)
                self.distanceBetweenTwoLocations(self.currentLocation, destination: otherloc, userid: userid2)
            }
        })

然后我在第二行收到一个错误:

Cannot call value of non-function type 'Any?!'

我唯一尝试的是将第二行更改为以下代码:

snapshot.value as! [String:AnyObject]

但这不对，没有包含“Dogs”，它警告我从未使用过 distanceBetweenTwoLocations 代码。

Answer 1

看到的问题是，当您实例化和初始化您的变量时，您告诉它它将接收的值将是一个 value。 对于名为 Dogs 的对象出现在这个类型为 AnyObject 的快照中.

但是 snapshot.value 是字典类型，即 [String:AnyObject] , NSDictionary ..

还有 Dogs您检索的节点类型为字典或数组。

基本上您应该避免将值存储在 AnyObject 类型的变量中

试试这个:-

      FIRDatabase.database().reference().child("Posts").child("post1").observe(.childAdded, with: { snapshot in
        if let currentData = (snapshot.value! as! NSDictionary).object(forKey: "Dogs") as? [String:AnyObject]{

            let mylat = (currentData["latitude"])! as! [String]
            let mylat2 = Double((mylat[0]))
            let mylon = (currentData["longitude"])! as! [String]
            let mylon2 = Double((mylon[0]))
            let userid = (currentData["User"])! as! [String]
            let userid2 = userid[0]
            let otherloc = CLLocation(latitude: mylat2!, longitude: mylon2!)
            self.distanceBetweenTwoLocations(self.currentLocation, destination: otherloc, userid: userid2)
        }
    })

PS:-看到您的 JSON 结构，您可能想将其转换为字典而不是数组