Firebase Remove Children From Recyclerview Adapter

I need to remove child from Firebase after onClick from RecyclerView Adapter. I have something like this: public void onBindViewHolder(final ViewHolder holder, final int position)

Solution 1:

Recap:

Suppose you have a Database reference responsible for fetching your entire list of items called: mDatabase,which you should have already innitialized:

private DatabaseReference mDatabase;

And in your activity main method:

@OverrideprotectedvoidonCreate(Bundle savedInstanceState) {
mDatabase = FirebaseDatabase.getInstance().getReference();

And fetching your Data as:

  mDatabase = FirebaseDatabase.getInstance().getReference()
            .child("myitems").child(someKey);

Now that your data is displaying in your recycler view,at some point we will use our mDatabase to successfully delete an item below:

In your ViewHolder:

You have to first get a reference of the position of your item from your ViewHolder which is directly referencing the item from the database:

Assuming your Database reference is itemRef:

final DatabaseReference ** itemRef**

You would have to assign the database reference to the position of each item by using getRef:

finalDatabaseReferenceitemRef= getRef(position);

And there after use the reference to your position and database reference and assign it to a String which you will use to get the unique key of your item:

finalStringmyKey= itemRef.getKey();//you can name the myKey whatever you want.

finally we can access the key to delete an item:

In this example:Lets assume your delete button is:delBtn,and your ViewHolder is GameViewHolder viewHolder as below:

@Override
protected void onBindViewHolder(@NonNull GameViewHolder viewHolder,int position,
@NonNull final Game model)

Deleting an Item:

In your ViewHolder/referencing the viewHolder...we set an o'clock listener on our button and use our database reference for all items to get the particular items position and remove the value:

viewHolder.delBtn.setOnClickListener(v -> {
mDatabase.child(myKey).removeValue();

Our Entire deleting item code would therefore look like this:

@NonNull@Overridepublic GameViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
LayoutInflaterinflater= LayoutInflater.from(viewGroup.getContext());
returnnewGameViewHolder(inflater.inflate(R.layout.single_item, viewGroup, false));}

@OverrideprotectedvoidonBindViewHolder(@NonNull GameViewHolder viewHolder,int position,
@NonNullfinal Game model){
finalDatabaseReferenceitemRef= getRef(position);              
finalStringmyKey= itemRef.getKey();//you can name the myKey whatever you want.


 viewHolder.delBtn.setOnClickListener(newView.OnClickListener() {
                    @OverridepublicvoidonClick(View v) {
  mDatabase.child(myKey).removeValue();

                    }
                });

More details from this blog

Firebase Official Documents

Solution 2:

User removeValue method and add listener to know the status of the delete operation as shown below. For complete example http://www.zoftino.com/firebase-realtime-database-android-example#realtime-database-delete

FirebaseDatabase.getInstance().getReference()
                .child("notifications").child(toId.toString()).removeValue()
                .addOnCompleteListener(new OnCompleteListener<Void>() {
                    @Override
                    public void onComplete(@NonNull Task<Void> task) {
                        if (task.isSuccessful()) {
                            Log.d("Delete", "Notification has been deleted");
                        } else {
                            Log.d("Delete", "Notification couldn't be deleted");
                        }
                    }
                });

Solution 3:

In order to delete a Firebase database record, you don't need to use a listener, you only need to use removeValue() method directly on the reference like this:

messageRef.child("notifications").child(toId.toString()).removeValue();