delete Table View Cells from Firebase - ios

Question

I have a table View full of appended messages with the logged in user and other users of the app. When I swipe a cell, I want to be able to delete it from Firebase and also automatically from the tableView. I managed to get the cell deleted from Firebase but not from the tableView. This is how the messages are initially loaded into the tableView:
func loadData()
{
guard let uid = FIRAuth.auth()?.currentUser?.uid else {
return
}
FIRDatabase.database().reference().child("messages").observeSingleEvent(of: .value, with: { (snapshot:FIRDataSnapshot) in
if let postsDictionary = snapshot .value as? [String: AnyObject] {
for post in postsDictionary {
let messages = post.value as! [String: AnyObject]
for (id, value) in messages {
let info = value as! [String: AnyObject]
let convoId = info["convoId"]
let toId = info["ReceiverId"] as! String!
let fromId = info["senderId"] as! String!
if (toId == self.loggedInUserUid || fromId == self.loggedInUserUid) {
let refs = FIRDatabase.database().reference().child("user-messages").child(convoId as! String).child(uid)
refs.observe(.childAdded, with: { (snapshot) in
self.messageId = snapshot.key
let ref = FIRDatabase.database().reference().child("messages").child(convoId as! String).child(self.messageId!)
ref.observeSingleEvent(of: .value, with: { (snapshot) in
if let dictionary = snapshot.value as? [String: AnyObject] {
let message = Message(dictionary: dictionary)
if let receiver = message.convoId {
self.messagesDictionary[receiver] = message
self.messages = Array(self.messagesDictionary.values)
print(self.messages)
self.messages.sort(by: { (message1, message2) -> Bool in
return (message1.timestamp?.int32Value)! > (message2.timestamp?.int32Value)!
})
}
//this will crash because of background thread, so lets call this on dispatch_async main thread
DispatchQueue.main.async(execute: {
self.MessageTableView.reloadData()
})
}
}, withCancel: nil) })}
}
}}})
}
Here is how I perform the delete function in Firebase and attempt to perform a delete function in the tableView:
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
guard let uid = FIRAuth.auth()?.currentUser?.uid else {
return
}
let message = messages[(indexPath.row)]
self.deletemessage = message.convoId
FIRDatabase.database().reference().child("messages").observeSingleEvent(of: .value, with: { (snapshot:FIRDataSnapshot) in
if let postsDictionary = snapshot .value as? [String: AnyObject] {
for post in postsDictionary {
let messages = post.value as! [String: AnyObject]
for (id, value) in messages {
let info = value as! [String: AnyObject]
let convoId = info["convoId"]
let ref = FIRDatabase.database().reference().child("user-messages").child(self.deletemessage!).child(uid)
ref.observe(.childAdded, with: { (snapshot) in
self.messageId = snapshot.key
FIRDatabase.database().reference().child("user-messages").child(self.deletemessage!).child(uid).child( self.messageId!).removeValue(completionBlock: { (error, ref) in
if error != nil {
print("error \(error)")
}else{
}})})}}}})
self.messages.remove(at: indexPath.row)
self.MessageTableView.deleteRows(at: [indexPath], with: .automatic)
}
}
it deletes from the tableView but crashes and gives me an error on self.messages.remove(at: indexPath.row) fatal error: Index out of Range.

Answer 1

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
let state = id[indexPath.row] //it store the child key to be removed. here id array is not displayed but used as backend process
print(state) // (Not required)
names.remove(at: indexPath.row) //Remove the selected name from array used in TableView that is displayed in cell
tableView.deleteRows(at: [indexPath], with: .fade) // TableView Animation
Database.database().reference().child("artists").child(id[indexPath.row]).removeValue() // remove the child referred using id from database
id.remove(at: indexPath.row) // removing selected if from id array locally
}
}
Try the following code In your case please and let me know issue still Exists
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
guard let uid = FIRAuth.auth()?.currentUser?.uid else {
return
}
let message = messages[(indexPath.row)]
self.deletemessage = message.convoId
FIRDatabase.database().reference().child("messages").observeSingleEvent(of: .value, with: { (snapshot:FIRDataSnapshot) in
if let postsDictionary = snapshot .value as? [String: AnyObject] {
for post in postsDictionary {
let messages = post.value as! [String: AnyObject]
for (id, value) in messages {
let info = value as! [String: AnyObject]
let convoId = info["convoId"]
let ref = FIRDatabase.database().reference().child("user-messages").child(self.deletemessage!).child(uid)
ref.observe(.childAdded, with: { (snapshot) in
self.messageId = snapshot.key
FIRDatabase.database().reference().child("user-messages").child(self.deletemessage!).child(uid).child( self.messageId!).removeValue(completionBlock: { (error, ref) in
if error != nil {
print("error \(error)")
}
})
})
}
}}})
self.messages.remove(at: indexPath.row)
self.MessageTableView.deleteRows(at: [indexPath], with: .automatic)
}
}
Try this it occur because you are deleting value correct but under a handler which even caused a error in my project . data in messages is loaded from database so if value is not delete from database it will update again even if u remove from array. so please try this code