ios - 如何解决这个: "Could not cast value of type ' NSTaggedPointerString' (0x105d25e88) to 'NSDictionary' (0x105d261a8).”

Question

我正在使用具有以下结构的 Firebase:

当我单击“保存”按钮时，这是写入 firebase 的代码:

let savedDB = Database.database().reference().child("saved")
let postid = detailpost?.postid
let uid = Auth.auth().currentUser?.uid
let key = savedDB.child(postid!).key
let childUpdates : [String : String] = ["\(uid!)/\(key)/": "true"]
savedDB.updateChildValues(childUpdates)

要尝试读取数据，这是我的代码:

if let uid = Auth.auth().currentUser?.uid{
     let savedDB = Database.database().reference().child("saved").child(uid)
     savedDB.observe(.childAdded) { (snapshot) in
     let snapshotValue = snapshot.value as! Dictionary<String,String>
     if let savedpostid = snapshotValue["postid"]{
     ......

当我的代码到达这一步时，它崩溃了，并显示以下错误消息:

Could not cast value of type 'NSTaggedPointerString' (0x111688e88) to 'NSDictionary' (0x1116891a8).

我无法弄清楚导致此问题的原因以及如何解决它。有人可以建议吗？谢谢。

Answer 1

更改此:

let snapshotValue = snapshot.value as! Dictionary<String,String>

进入此:

 let snapshotValue = snapshot.value as! FIRDataSnapshot

查看此链接以获取更多信息:https://firebase.google.com/docs/reference/ios/firebasedatabase/api/reference/Classes/FIRDataSnapshot

A FIRDataSnapshot contains data from a Firebase Database location. Any time you read Firebase data, you receive the data as a FIRDataSnapshot.