这是我的代码before迁移到 Swift 3：
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)
}
})
这是我的代码after迁移到 Swift 3：
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错误：
无法调用非函数类型“Any?!”的值
我唯一尝试的是将第二行更改为以下代码：
snapshot.value as! [String:AnyObject]
但这是不对的，其中没有“狗”，它给了我一个警告：distanceBetweenTwoLocations代码从未使用过。
看到的问题是，当您是实例并初始化变量时，您告诉它它将收到的值将是value对于名为Dogs存在于该快照中，其类型为AnyObject.
But snapshot.value是字典类型，即[String:AnyObject],NSDictionary..
And the Dogs您检索的节点的类型为“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
尝试这个：-
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 JSON 结构，您可能想将其转换为字典而不是数组
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