Firebase未加载数据

Question

这是我第一次使用firebase，我想要做的是将数据库中存储的4个值调用到单个字符串，这些代码和数据库的外观如下所示。我在数据库中启用了读写功能。任何帮助将不胜感激。

我从这里获得了一些代码Type 'Any' has no subscript members (firebase)

并且一直在关注将数据存储在数组https://youtu.be/XIQsQ2injLo

中的教程

但到目前为止我没有成功。 感谢

import UIKit
import Firebase
import FirebaseDatabase


class ViewController: UIViewController {

@IBOutlet var Silver: UILabel!
@IBOutlet var Aqua: UILabel!
@IBOutlet var Orange: UILabel!
@IBOutlet var Purple: UILabel!




@IBAction func loadData(_ sender: Any) {

    let databaseRef = FIRDatabase.database().reference()

    databaseRef.queryOrderedByKey().observe(.childChanged, with: {
        snapshot in


        let content2 = (snapshot.value as? NSDictionary)?["aqua"] as? String ?? ""
        let content3 = (snapshot.value as? NSDictionary)?["orange"] as? String ?? ""
        let content4 = (snapshot.value as? NSDictionary)?["purple"] as? String ?? ""
        let content = (snapshot.value as? NSDictionary)?["silver"] as? String ?? ""



        print(content2)
        print(content3)
        print(content4)
        print(content)

        self.Silver.text = content
        self.Aqua.text = content2
        self.Orange.text = content3
        self.Purple.text = content4
    })



}




override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    let databaseRef = FIRDatabase.database().reference()

    databaseRef.queryOrderedByKey().observe(.childChanged, with: {
        snapshot in

        let content = (snapshot.value as? NSDictionary)?["silver"] as? String ?? ""
        let content2 = (snapshot.value as? NSDictionary)?["aqua"] as? String ?? ""
        let content3 = (snapshot.value as? NSDictionary)?["orange"] as? String ?? ""
        let content4 = (snapshot.value as? NSDictionary)?["purple"] as? String ?? ""


        self.Silver.text = content
        self.Aqua.text = content2
        self.Orange.text = content3
        self.Purple.text = content4
    })



}




}

Answer 1

您已使用.childChanged观察者尝试下面的代码

 ref.observeSingleEvent(of: .value, with: { (snapshot) in
  // Get user value
  let value = snapshot.value as? NSDictionary
  let username = value?["username"] as? String ?? ""


  // ...
  }) { (error) in
    print(error.localizedDescription)
}