Question

正如标题所示，我正在尝试从firebase数据库中检索一些数据，但我的代码无效。我有三个孩子（我想这就是你怎么称呼它们）里面的“帖子”，称为“标题”，“描述”和“用户名”，我试图获取所有这些并将它们附加到变量中以便以后使用它们，但它只检索每个值的第一个值，尽管事实上有5个值。谁知道为什么？顺便说一句，我在我的ViewDidLoad上调用了这个函数。

let postDB = Database.database().reference().child("Posts")
postDB.queryOrderedByKey().observeSingleEvent(of: .value) { (snapshot) in
    if let snapshotValue = snapshot.value as? NSDictionary {

    let postTitle = snapshotValue["title"] as? String
    let postUsername = snapshotValue["username"] as? String
    let postDesc = snapshotValue["description"] as? String

    let postArray = postStruct(title: postTitle, description: postDesc, username: postUsername)
    self.newPost.insert(postArray, at: 0)

    }

My Firebase Database.

Answer 1

尝试此操作 - 代码将替换您当前在快照处理程序中拥有的内容。

if let firebaseList = snapshot.children.allObjects as? [FIRDataSnapshot] {
        if let swiftList = snapshot.value as? [String:AnyObject] {
            for firebaseItem in firebaseList {
                let childID = firebaseItem.key as String
                let swiftItem = swiftList[childID]
                let postTitle = swiftItem?["title"] as? String
                let postUsername = swiftItem?["username"] as? String
                let postDesc = swiftItem?["description"] as? String
                let postArray = postStruct(title: postTitle, description: postDesc, username: postUsername)
                self.newPost.insert(postArray, at: 0)
            }
        }
    }
}

Answer 2

import UIKit
import FirebaseDatabase

class HomeViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
    // MARK: - variables
    var postDB: DatabaseReference!

    override func viewDidLoad() {
        super.viewDidLoad()

        // getting a node from database //
        postDB = Database.database().reference().child("Posts")

        // observing data changes //
        postDB.observe(DataEventType.value) { (dataSnapshot) in
            self.postArray.removeAll()
            if dataSnapshot.childrenCount > 0 {
                for post in dataSnapshot.children.allObjects as! [DataSnapshot] {
                    let object = post.value as! [String: Any]
                    let description = object["description"] as! String
                    let title = object["title"] as! String
                    let userName = object["username"] as! String
                    let model = postStruct(title: title, description: description, username: userName))
                    self.postArray.append(model)
                }
            }
            self.tableView.reloadData()
        }
    }
}

代码仅从Firebase中的数据中检索一个值

2 个答案: