CODEWITHSUNDEEP
javaandroidfirebasefirebase-realtime-database
user4744059
user4744059

Reputation:

How to delete selected child on Firebase Database Android

I am trying to delete a child from the database by setting the unique Key to null. What I do is - I press and hold on a List Item to get the Alert Dialog and then press to delete the entry I have selected. The problem is when I retrieve the key it returns me all the keys. And closest I managed to get so far was to delete everything from the database. Please check my code snapshots below:

 mLocationListView.setLongClickable(true);
    mLocationListView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {

            AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this)
                    .setTitle("Delete a Location")
                    .setMessage("Do you want to delete your location?")
                    .setPositiveButton("Delete", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {

//Problem is here. if I exclude .child(pushKey)everything is deleted from the database. 
                                DatabaseReference db_node = FirebaseDatabase.getInstance().getReference().getRoot().child("locations").child(pushKey);

                        db_node.setValue(null);
                        }
                    });
                AlertDialog alert = builder.create();
                alert.show();
            return true;
        }
    });

Here is how I retrieve pushKey. Any suggestions how to do it in more proper way? (if there is one)

 queryRef.addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {
            locationCurrent = dataSnapshot.getValue(LocationCurrent.class);
            mLocationAdapter.add(locationCurrent);
            pushKey = dataSnapshot.getKey();
            Log.i("PUSH KEY ", pushKey);

        }

        @Override
        public void onChildChanged(DataSnapshot dataSnapshot, String s) {
            locationCurrent = dataSnapshot.getValue(LocationCurrent.class);


        }

        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {

        }

        @Override
        public void onChildMoved(DataSnapshot dataSnapshot, String s) {

        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

I was thinking of putting the Key to the database as well but there is no point and there must be the most efficient solution.

UPDATE:

I have tried doing this with another method attaching a single value event listener to the query but it does not work because I cannot determine which list item I click on so I delete the whole database. Basically, I need to click on a list item and delete it. But It does not work. I did exactly as in the link here below:

How to delete from firebase realtime database?

Any suggestions?

Upvotes: 1

Views: 4417

Answers (1)

Saurabh Padwekar
Saurabh Padwekar

Reputation: 4074

Add a transient variable called refKey in your LocationCurrent.class. Save the ref in onChildAdded

public void onChildAdded(DataSnapshot dataSnapshot, String s) {
    locationCurrent = dataSnapshot.getValue(LocationCurrent.class);
    locationCurrent.setRefKey(dataSnapshot.getKey()); 
    mLocationAdapter.add(locationCurrent);
}

And on delete click do this :

mLocationListView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
    @Override
    public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
    DatabaseReference db_node = FirebaseDatabase.getInstance().getReference().child("locations").child(mLocationAdapter.getItem(position).getRefKey());
    db_node.removeValue();
});

Upvotes: 2

Related Questions