将数据从Firebase获取到UITableViewController-Swift

Question

I am trying to get data from my Firebase database into my UITableViewController .

The meaning of the UITableViewController is to display who has liked the post you are visiting.

When someone likes a post, their userID is being placed in the post under the category likesForPost - as you can see here:

As you can see 1 person has already liked this post (the black box is a userID ).

The problem is that I do not get any data displayed on my cell. I am trying to display the userID on my cell but nothing shows. I do however get the number of cells equal to the number of people that has liked the post.

I should explain the that viaSegue is getting a key from a prepareForSegue and yes it is displaying the correct key, so that is not the problem :-)

Here is my UITableViewController :

import UIKit
import FirebaseDatabase
import FirebaseAuth
import FBSDKCoreKit
import FirebaseStorage

class viewLikesTableViewController: UITableViewController {
    var viaSegue = "Nothing"
    var updates = [LikeSweet]()

    override func viewDidLoad() {
        super.viewDidLoad()

        let logo = UIImage(named: "logo.png")
        let imageView = UIImageView(image:logo)
        self.navigationItem.titleView = imageView

        print(viaSegue)

        startObersvingDB()
    }

    func startObersvingDB() {
            FIRDatabase.database().reference().child("feed-items").child(self.viaSegue).child("likesForPost").observeEventType(.Value, withBlock: { (snapshot: FIRDataSnapshot) in
                    // Get user value
                var newUpdates = [LikeSweet]()

                for update in snapshot.children {
                    let updateObject = LikeSweet(snapshot: update as! FIRDataSnapshot)
                    newUpdates.append(updateObject)

                }

                self.updates = newUpdates
                self.tableView.reloadData()
            }) { (error: NSError) in
                print(error.description)
            }
    }

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

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return updates.count
    }

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        tableView.deselectRowAtIndexPath(indexPath, animated: true)

        let update = updates[indexPath.row]

        let allDataSend = update.userID
        self.performSegueWithIdentifier("showProfile", sender: allDataSend)
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell:viewLikesTableViewCell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! viewLikesTableViewCell

            let update = updates[indexPath.row]

            cell.nameLabel.text = update.userID
        return cell
    }
}

You might also want the LikeSweet code:

import Foundation
import FirebaseDatabase
import FirebaseAuth
import UIKit

struct LikeSweet {
    let key: String!
    let userID: String!
    let itemRef: FIRDatabaseReference?
    let path : String!

    init (userID: String, key: String = "") {
        self.key = key
        self.userID = userID
        self.itemRef = nil
        // self.path = dataPath
        self.path = ""
    }

    init (snapshot: FIRDataSnapshot) {
        key = snapshot.key
        itemRef = snapshot.ref
        path  = key
        if let theFeedContent = snapshot.value!["userID"] as? String {
            userID = theFeedContent
        } else {
            userID = ""
        }
    }

    func toAnyObject() -> AnyObject {
        return ["userID":userID]
    }
}

Answer 1

It should be as simple as calling your

self.updates = newUpdates
self.tableView.reloadData()

on the main queue. You can't update the UI on a non-main thread.

Try and do this

DispatchQueue.main.async {
  self.updates = newUpdates
  self.tableView.reloadData()
}