FIRInvalidArgumentException，原因：文档路径不能为空

Question

我正在尝试访问我从 Firebase 快照创建的字典中的一些值，我使用这些值来访问我的 firestore 中的一些文档，但是这些值返回为空，因此我使用这些值的路径是空的，我可以t 访问 Firestore。

我不确定这些值是否嵌套在字典中，我尝试搜索访问嵌套字典，但出现其他错误。

这是 output

snapshot Optional({
16640500463403668 =     {
    ReciverID = "manarx224@gmail.com";
    RewardKey = "Reward_25";
    isScanned = 1;
};
}) 
Scanned successfully 
16640500463403668 
Dictionary is:
Optional({ 16640500463403668 = { ReciverID = "manarx224@gmail.com"; RewardKey = "Reward_25"; isScanned = 1; }; }) 
resciver id is
RewardKey id is

2022-09-25 02:31:20.924590+0300 KhutaaScannser[30891:1892245] *** Terminating app due to uncaught exception 'FIRInvalidArgumentException', reason: 'Document path cannot be empty.'

这是我的代码：

let ref = ref.child("AllQRCodes")
ref.getData { [self] (error, snapshot) in
    print("snapshot \(snapshot.value as Any)")
   
    if let value = snapshot.value as? [String: Any] {
        for key in value.keys {

            if key == QRnumber {
        
                self.ref.child("AllQRCodes").child(QRnumber).child("isScanned").setValue(true)
                print("Scanned successfully")
                self.messageLabel.text = "Succefully Scanned"
                print(key)
                
                let dictionary = snapshot.value as? NSDictionary
                print("Dictionary is:  " )
                print(dictionary)
                
                var ReciverID = dictionary?["ReciverID"] as? String ?? ""
                var RewardKey = dictionary?["RewardKey"] as? String ?? ""
                
                print("resciver id is" + ReciverID)
                print("RewardKey is "+RewardKey)
                
                db.collection("users").document(ReciverID).collection("UserRewards").document(RewardKey).setData( ["isScanned": true], merge: true)
                
                print("Scanned successfully")
                self.messageLabel.text = "Succefully Scanned"

                self.ref.child("AllQRCodes").child(QRnumber).removeValue()
                
                break

Answer 1

您没有从正确的子快照中读取。

var ReciverID = dictionary?["QRnumber"]["ReciverID"] as? String ?? ""

您可能需要在其中进行一些额外的 null 处理，因此如果您收到关于此的错误，请搜索错误消息。