Firebase Snapshot正常工作以检索用户信息，但无法检索个人资料图片-Swift

Question

我的快照出现了一个奇怪的问题，在该快照中，用户名和电子邮件已被提取，但是对于个人资料照片，快照返回nil。

func displayUserInformation() {

    let uid = Auth.auth().currentUser?.uid
    Database.database().reference().child("users").child(uid!).observeSingleEvent(of: .value, with: { (snapshot) in


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

            self.username.text! = (dictionary["username"] as? String)!
            self.email.text! = (dictionary["email"] as? String)!

            let profileImageUrl =  (dictionary["photoUrl"] as? String)!
            let url = URL(string: profileImageUrl)
            URLSession.shared.dataTask(with: url!, completionHandler: { (data, response, error) in
                    if error != nil {
                        print(error!)
                        return
                    }
                    DispatchQueue.main.async {
                        self.profilePicture.image? = UIImage(data: data!)!
                        print(data!)
                    }
                }).resume()


            print(profileImageUrl)
            print(snapshot)
        }
    }, withCancel: nil)
}

快照正在运行，profileUrl确实显示了数据，所以我不知道可能是什么问题。这是print（profileImageUrl）显示的内容和快照

https://firebasestorage.googleapis.com/v0/b/gastet-4cfd2.appspot.com/o/profileImages%2F031F0B9F-AA41-4C16-8446-CD07893F2CA7.jpg?alt=media&token=c0e07615-8166-40e7-8d92-22bb8fbc8c8e
Snap (wL40cuYrGAVNdCVvCGUhKsD64RH2) {
    email = "ximeft29@gmail.com";
    photoUrl = "https://firebasestorage.googleapis.com/v0/b/gastet-4cfd2.appspot.com/o/profileImages%2F031F0B9F-AA41-4C16-8446-CD07893F2CA7.jpg?alt=media&token=c0e07615-8166-40e7-8d92-22bb8fbc8c8e";
    username = ximeft29;
}

Answer 1

我已经在一个示例项目中复制了您的示例，并成功地获得了它以从URL异步获取图片。

我还重写了该函数，以更优雅地处理数据展开。任何问题都可以问！

func displayUserInformation() {

    if let currentUser = Auth.auth().currentUser {

        Database.database().reference().child("users").child(currentUser.uid).observeSingleEvent(of: .value) { (snapshot) in

            if let dictionary = snapshot.value as? [String: AnyObject],
               let username = dictionary["username"] as? String,
               let email = dictionary["email"] as? String,
               let urlString = dictionary["photoUrl"] as? String,
               let url = URL(string: urlString) {

                self.username.text = username // Set the username
                self.email.text = email // Set the email

                /*
                 * Fetch the image asyncronously
                 */
                URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in

                    if let error = error {
                        print("There was an error fetching the image from the url: \n", error)
                    }

                    if let data = data, let profilePicture = UIImage(data: data) {
                        DispatchQueue.main.async() {
                            self.profilePicture.image = profilePicture // Set the profile picture
                        }
                    } else {
                        print("Something is wrong with the image data")
                    }

                }).resume()
            }
        }
    }
}