refresh tableView after deleting cell

Question

I have a tableView with data populated from Firebase, when I click a delete button the data is removed from Firebase but it remains on my app and it doesn't remove the data from the tableView until I close the app and reopen it. Here is how I set up the delete function:

func deletePost() {
        let uid = FIRAuth.auth()!.currentUser!.uid
        let storage = FIRStorage.storage().reference(forURL: "gs://gsignme-14416.appspot.com")
        FIRDatabase.database().reference().child("posts").child(uid).observe(.childAdded, with: { (snapshot) in

            let indexPath = self.selectedIndex

            let post = self.posts[(indexPath?.row)!] as! [String: AnyObject]
            self.key = post["postID"] as? String

            self.itemsRef = FIRDatabase.database().reference().child("posts").child(uid).child(self.key!)


        // Remove the post from the DB
        FIRDatabase.database().reference().child("books").child(self.key!).removeValue { error in
            if error != nil {
                print("error \(error)")
            }
        }

            })
        self.TableView.reloadData()
    }

Here are the delegate and datasource:

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

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
         posts.count
}

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
       self.selectedIndex = indexPath
        self.didExpandCell()
        if isExpanded && self.selectedIndex == indexPath{
            print(indexPath)
        } else{
                    }}

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {

        if isExpanded && self.selectedIndex == indexPath{
            return 300
        }
              return 126
    }


    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cells", for: indexPath) as! ProfileTableViewCell

        //Configure the cell
        let post = self.posts[indexPath.row] as! [String: AnyObject]
        cell.Title.text = post["title"] as? String
        cell.Author.text = post["Author"] as? String
        cell.ISBN10.text = post["ISBN10"] as? String
        return cell
    }

I attempted to add a tableview.reloaddata at the end of the function but that doesn't help. What am I doing wrong?

Answer 1

Delete the removed object from your array also. Your table view gets populated using posts array, not from Firebase object itself. when you click delete button the data is removed from Firebase but it remains on your app, as you have not deleted that object from your array i.e. posts thats why it doesn't remove the data from the tableView until you close the app and reopen it.

You need the remove the deleted object from your posts array and reload that rows to get the effect.

 self.posts.remove(at: indexPath.row)

and then reload that specific row itself.

 self.tableView.beginUpdates
 tableView.reloadRows(at: [indexPath], with: .top)
 self.tableView.endUpdates;

In your case

 FIRDatabase.database().reference().child("books").child(self.key!).
   removeValue { error in
        if error != nil {
            print("error \(error)")
        } else{
          self.posts.remove(at: indexPath.row)
          self.tableView.beginUpdates
          tableView.reloadRows(at: [indexPath], with: .top)
          self.tableView.endUpdates;
        }
    }
  })

Hope it helps. Happy Coding!!

Answer 2

Remove your object from posts array and then reload your tableView in main queue one you remove your object from firebase.

Check below code:

func deletePost() {
    let uid = FIRAuth.auth()!.currentUser!.uid
    let storage = FIRStorage.storage().reference(forURL: "gs://gsignme-14416.appspot.com")
    FIRDatabase.database().reference().child("posts").child(uid).observe(.childAdded, with: { (snapshot) in

        let indexPath = self.selectedIndex

        let post = self.posts[(indexPath?.row)!] as! [String: AnyObject]
        self.key = post["postID"] as? String

        self.itemsRef = FIRDatabase.database().reference().child("posts").child(uid).child(self.key!)


        // Remove the post from the DB
        FIRDatabase.database().reference().child("books").child(self.key!).removeValue { error in
            if error != nil {
                print("error \(error)")
            } else {
                //Here remove your object from table array
                self.posts.remove(at: indexPath?.row)
                //Reload your tableview in main queue
                DispatchQueue.main.async{
                    self.TableView.reloadData()
                }
            }
        }

    })
}

Didn't tested it so let me know if you still have issue with above code.

Answer 3

        func deletePost() {
                let uid = FIRAuth.auth()!.currentUser!.uid
                let storage = FIRStorage.storage().reference(forURL: "gs://gsignme-14416.appspot.com")
                FIRDatabase.database().reference().child("posts").child(uid).observe(.childAdded, with: { (snapshot) in

                    let indexPath = self.selectedIndex

                    let post = self.posts[(indexPath?.row)!] as! [String: AnyObject]
                    self.key = post["postID"] as? String

                    self.itemsRef = FIRDatabase.database().reference().child("posts").child(uid).child(self.key!)


                // Remove the post from the DB
                FIRDatabase.database().reference().child("books").child(self.key!).removeValue { error in
                    if error != nil {
                        print("error \(error)")
                        return // use return here or use if else
                    }
// no error has occurred,hence move on to remove the post from the array
              self.posts.remove(at: indexPath.row)
 }     })
                DispatchQueue.main.async {
                   self.TableView.reloadData()
                 }

            }