Delete Tableview Cell, and Remove Data from Firebase

How to delete tableView cell and remove data from firebase

To delete a node in Firebase, first establish the path to that node by creating a reference to it, and then removeValue on that reference (or set the ref to nil which also removes it)

In brief

let eventToDelete = dataSource[indexPath.row] //get the event from the dataSource
let firebaseKey = eventToDelete.eventId //assuming the eventId is the node key
let eventRef = my_firebase.child("events").child(firebaseKey)
eventRef.removeValue()  //or eventRef.setValue(nil)

Delete tableView cell and remove data from firebase

Speaking at a high level, your tableView is backed by a dataSource, typically an array, which is the source for the content displayed in the tableView.

var userCommentArray = [UserComment]()

you should be loading data from Firebase and storing that data in the array as UserComment objects

class UserComment {
   var firebaseKey = ""
   var commentText = ""
   var uid = ""
}

the firebase_key property is the key to the node in Firebase, shown as -MH_xxxx in the screenshot and then the commentText and uid are is the child data of that node.

The indexes of the elements in the array match what's being shown in the tableView, so row0 matches the array index 0, row 1 matches the array index 1 etc.

When the user deletes row 1, you know that's index 1 in the array. read the object, get it's firebaseKey and then delete it from firebase, updating the array accordingly and then reloading your UI.

See my answer to your Other Question for details on that process.

delete tableView cell, and remove data from firebase

First, you don't delete a tableViewCell from Firebase, but you can remove the data from Firebase that you pull to populate your tableView.

Second, what you're doing wrong is trying to get a class value of ref from an array.

Third, after deleting the data from the web, you'll still need to remove the cell from the table which your code looks like it will do just fine but I'm putting it here for completeness.

To delete a value from Firebase you need to create a reference and then process things from there. Like this :

let ref = Database.database().reference(fromURL: yourProjectURL)
let groupRef= ref.child("groups").child(groupsArray[indexPath.row].key)
// ^^ this only works if the value is set to the firebase uid, otherwise you need to pull that data from somewhere else.
groupRef.removeValue()

Then delete the item from the array:

groupsArray.remove(at: indexPath.row)

And delete the row from the tableView:

tableView.deleteRows(at: [indexPath], with: .automatic)

Everything should look like this :

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
        let ref = Database.database().reference(fromURL: yourProjectURL)
        let groupRef= ref.child("groups").child(groupsArray[indexPath.row].key)
        // ^^ this only works if the value is set to the firebase uid, otherwise you need to pull that data from somewhere else.
        groupRef.removeValue()
        groupsArray.remove(at: indexPath.row)
        tableView.deleteRows(at: [indexPath], with: .fade)
    }
}

how to delete firebase with tableView cell SWIFT

The code in the question won't actually remove anything from the posts node.

Database.database().reference().child("posts").child("uid").removeValue()
                                                     ^^^^^

there is no child node that's has a key of the literal string "uid"

If there were a child node with a key of "uid", only that child would be removed. For example.

posts
   post_0
      author: "test_0"
   post_1
      author: "test_1"
   uid
      author: "test_2"
   post_2
      author: "test_3"

If the structure looked like that and the code was run, it would remove the node that had a key of "uid"

posts
   post_0
      author: "test_0"
   post_1
      author: "test_1"
   post_2
      author: "test_3"

EDIT:

Supposed I wanted to delete the post_1 node from posts. Here's how that would be done (there are other ways as well)

Database.database().reference().child("posts").child("post_1").removeValue()

EDIT 2: the good stuff

Based on comments, the actual issue is the OP doesn't know how to get to the specific node they want to delete. Here are two options

1) Query for the node (not recommended)
With this option, you would need to query for the node by some value. The key here is the value must exist within the node. So in my above structure query for the node where author = "test_1". The downside of this is there could be multiple authors "test_1" so this option has limitations

2) Recommended
Change your Swift model to also store the node key. It's not outlined in the question but typically a tableView is backed by a dataSource, an array, and that array contains models which match your Firebase data.

I'm addressing this at a high level with pseudo-code as there's not enough code in the question know specifics.

In this case it appears to be a listing of posts so a model would be

class PostClass {
   var post_id = ""
   var post_text = ""
   var author_uid = ""
   var photo_url = ""
}

then the dataSource array to store it

var postsArray = [PostClass]()

then when Firebase is read, create the object and store the key along with the data in each object

postsNode.observe.... { snapshot in
   let post = PostClass()
   post.post_id = snapshot.key  //<-  this is the important part
   post.post_text = snapshot.childSnapshot("post_text") as? String ?? "No Text"
....
   self.postArray.append(post)
}

So now all of the data from each node is stored and when it comes time to delete, just read that object from the dataSource, get the post_id and delete

let post = self.postArray[index of row to delete]
let postId = post.post_id

Database.database().reference().child("posts").child(postId).removeValue()

how to delete cell and data in firebase and swift 3

You are only deleting data for your UITableView. The logic that you need is to delete from your UITableView and Fireabase Database. As the firebase docs says you can either call removeValue, or setValue to nil or updateChildValues.

To make the deletion easier, I'd save the key of the object where the data is saved (snapshot.keys), so when you want to delete you can just get that key and perform actions.

How do I delete a cell from tableview

Without seeing all of the code it's hard to provide a specific example but let me cover this at a high level.

Suppose we have a posts class object

class PostsClass {
   var docId = ""
   var post = ""
}

and an class array (aka a 'dataSource') to store them in

var postsArray = [PostsClass]()

The first step is to load all of the posts from Firebase, storing the docId and post text in each class and then store the class in the dataSource array.

myFirebase.getDocuments { doc...
   for doc in documents { //iterate over the documents and populate the array
      let post = PostClass(populate with data from firebase)
      self.postsArray.add(post)
   }
}

the dataSouce array will look like this

postsArray[0] = some post
postsArray[1] = another post

etc, and all of that is displayed in a tableView.

The user then decides to delete the post at row 1. So they swipe row one, which fires a tableView delegate event letting the app know the index of the swiped row.

Step 1: You then get that post from the array based on the swiped row index

let postToDelete = self.postsArray[swiped index]
let docIdToDelete = postsToDelete.docID

Step 2: then remove it from the array

self.postsArray.deleteRow(atIndex: swiped index)

Step 3: then delete it from Firebase.

self.my_firebase.collection("posts").document(docIdToDelete).delete {....

Note that the func tableView:tableView:commit editingStyle will present the editing style of .delete when the row is supposed to be deleted and also provide the index in indexPath.row

How to delete files from Firebase Storage and Table View - Swift

UPDATE This is how i managed to solve my issue for deleting files in Storage the reference in Firestore and the downloaded file also i remove from the table directly.

This help me: Swift Firestore - Delete Table Cell and Remove Document from Firestore

    let localFileName = fileURLs[indexPath.row].lastPathComponent
     var storageURL = ""
     db.collection(K.FStore.customerCollectionName).document(documentListRef)
         .collection(K.FStore.docCollectionName).whereField("fileName", isEqualTo: localFileName).getDocuments{ snapshot, error in
         if let error = error {
             print(error.localizedDescription)
         } else {
             for document in snapshot!.documents {
                 //print("\(document.documentID) => \(document.data())")
                 let data = document.data()
                 if  let url = data["url"] as? String{
                     storageURL = url
                 }
        if document.documentID != "" {

         let storageRef = Storage.storage().reference()
         //Get the sotrage reference from firesore
         let fileRef = storageRef.child(storageURL)
         //Delete the specific file in firestore
         fileRef.delete { error in
             if let error = error{
                 print("Error while deleting the document \(error)")
             } else{
                 print("File deleted successfully")
                 //Delete the document from firestore
                 self.db.collection(K.FStore.customerCollectionName).document(self.documentListRef)
                     .collection(K.FStore.docCollectionName).document(document.documentID).delete(){ err in
                     if let err = err {
                         print("Error while deleting the document: \(err)")
                     } else {
                         //Get the local file path
                         let docsurl = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
                         let tempDirPath = docsurl.appendingPathComponent("\(K.FStorage.documentFolderName)/\(self.documentListRef)/\(localFileName)")
                         do {
                             //Delete the local file from path
                             try FileManager.default.removeItem(at: tempDirPath)
                         } catch  { print(error) }
                         print("Document successfully deleted")
                         
                         //Remove the file from the TableView
                         self.fileURLs.remove(at: indexPath.row)
                         tableView.deleteRows(at: [indexPath], with: .fade)

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