Swift Firebase TableView 数据 - DataEventType.value

Question

我正在调用“关注”的孩子，并查看登录用户的 UID 是否存在，并且是否有登录用户正在关注的另一个用户的孩子。

我正在将登录用户正在关注的人打印到表格视图中。第一个问题是我的代码，因为我知道在彼此之间有两个 firebase 调用是不好的做法，所以我需要有人教我一个更好的方法。由于糟糕的代码，当我取消关注其他用户并返回显示他们关注的登录用户列表的选项卡时，它显示了这一点（下图）。当登录的用户没有关注任何人时，它应该只显示“对不起！”文本，但仍保留用户关注的人。需要有人教我一种更好的方法来进行这种类型的 firebase 调用。代码和firebase JSON堆栈图像如下......在firebase JSON堆栈图像中，扩展的UID是登录用户，子用户是登录用户关注的另一个用户。我需要一种更好的方法来调用和提取这些信息，我只是不知道如何做。

func getFollowingData() {

    Database.database().reference().child("following").child(uid!).observe(DataEventType.value, with: { (snapshot) in
        if snapshot.exists() {
            print("Got Snapshot")
            Database.database().reference().child("following").child(self.uid!).observe(.childAdded, with: { (snapshot) in
                if snapshot.exists() {
                    print(snapshot)
                    let snapshot = snapshot.value as? NSDictionary
                    self.listFollowing.append(snapshot)
                    self.followingTableView.insertRows(at: [IndexPath(row:self.listFollowing.count-1,section:0)], with: UITableViewRowAnimation.automatic)
                    self.followingTableView.backgroundView = nil
                }
            })
        } else {
            print("No Snapshot")
            self.followingTableView.backgroundView = self.noDataView
        }
    })
}

Answer 1

想通了，只需要按照我之前在其他提要上的方式进行即可。

import UIKit
import Firebase

class BusinessFollowing: UITableViewController {

@IBOutlet var noDataView: UIView!
@IBOutlet var followingTableView: UITableView!

var yourFollowing = [Information]()

var listFollowing = [NSDictionary?]()
var databaseRef = Database.database().reference()
let uid = Auth.auth().currentUser?.uid


var loggedInUser = Auth.auth().currentUser
var loggedInUserData:NSDictionary?

var following = [String]()

override func viewDidLoad() {
    super.viewDidLoad()

    self.followingTableView.backgroundView = nil


}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    self.followingTableView.reloadData()
    self.yourFollowing.removeAll()
    self.following.removeAll()

    getFollowingData()

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    super.prepare(for: segue, sender: sender)
    if segue.identifier == "following" {
        // gotta check if we're currently searching
            if let indexPath = followingTableView.indexPathForSelectedRow {
                let user = listFollowing[indexPath.row]
                let controller = segue.destination as? ExploreBusinessProfileSwitchView
                controller?.otherUser = user
            }
    }
}

override func numberOfSections(in tableView: UITableView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    // #warning Incomplete implementation, return the number of rows
    return self.yourFollowing.count
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! BusinessFollowingCell
    let following = yourFollowing[indexPath.row]

    let businessName = following.businessName
    let businessStreet = following.businessStreet
    let businessCity = following.businessCity
    let businessState = following.businessState

    cell.businessName.text = businessName
    cell.businessStreet.text = businessStreet
    cell.businessCity.text = businessCity
    cell.businessState.text = businessState

    // cell.businessName?.text = self.listFollowing[indexPath.row]?["businessName"] as? String
    // cell.businessStreet?.text = self.listFollowing[indexPath.row]?["businessStreet"] as? String
    // cell.businessCity?.text = self.listFollowing[indexPath.row]?["businessCity"] as? String
    // cell.businessState?.text = self.listFollowing[indexPath.row]?["businessState"] as? String

    return cell
}

func getFollowingData() {
    self.yourFollowing.removeAll()
    self.following.removeAll()
    self.followingTableView.reloadData()

    Database.database().reference().child("Businesses").child((loggedInUser?.uid)!).child("following").observe(.value, with: { snapshot in
        if snapshot.exists() {
            MBProgressHUD.showAdded(to: self.view, animated: true)
            let databaseRef = Database.database().reference()
            databaseRef.child("Businesses").queryOrderedByKey().observeSingleEvent(of: .value, with: { (usersSnapshot) in
                let users = usersSnapshot.value as! [String: AnyObject]
                for (_, value) in users {
                    if let userID = value["uid"] as? String {
                        if userID == Auth.auth().currentUser?.uid {
                            print(value)
                            if let followingUsers = value["following"] as? [String : String] {
                                for (_,user) in followingUsers {
                                    self.following.append(user)
                                }
                            }
                            databaseRef.child("following").queryOrderedByKey().observeSingleEvent(of: .value, with: { (postsSnapshot) in
                                let posts = postsSnapshot.value as! [String: AnyObject]

                                for (_, post) in posts {
                                    for (_, postInfo) in post as! [String: AnyObject] {
                                        if let followingID = postInfo["uid"] as? String {
                                            for each in self.following {
                                                if each == followingID {
                                                    guard let uid = postInfo["uid"] as! String? else {return}
                                                    guard let name = postInfo["businessName"] as! String? else {return}
                                                    guard let address = postInfo["businessStreet"] as! String? else {return}
                                                    guard let state = postInfo["businessState"] as! String? else {return}
                                                    guard let city = postInfo["businessCity"] as! String? else {return}

                                                    self.yourFollowing.append(Information(uid: uid, businessName: name, businessStreet: address, businessCity: city, businessState: state))
                                                }

                                                self.followingTableView.backgroundView = nil
                                                self.followingTableView.reloadData()
                                            }
                                        }
                                    }
                                }
                                MBProgressHUD.hide(for: self.view, animated: true)
                            }) { (error) in
                                print(error.localizedDescription)
                            }
                        }
                    }
                }

            })
        } else {
            print("Not following anyone")
            self.followingTableView.backgroundView = self.noDataView
            MBProgressHUD.hide(for: self.view, animated: true)
        }
    })

}

}