How Can I Fill The Recylerview With Firebase Realtime Database Data?

I tried so many solutions about this, but none of this resolve my problem. I can not reach the database using recyclerview. I have firebase realtime database data like this; Tag

Solution 1:

Get The data with child name ds.child("SubTag").getValue()

  dbRefTags.addValueEventListener(new ValueEventListener() {
                @Override
                public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                    for (DataSnapshot parentDS : dataSnapshot.getChildren()) {
                        Log.d("Tag:", String.valueOf(parentDS.getKey()));
                        for (DataSnapshot ds : parentDS.getChildren()) {
                            Tags tags = new Tags();
                            tags.setMainTag(parentDS.getKey());
                            tags.setSubTag(ds.child("SubTag").getValue().toString());
                            Log.d("Tag: -> SubTag)", tags.getSubTag());
                            tagsList.add(tags);
                        }
                    }
                    tagAdapter.notifyDataSetChanged();
                }

                @Override
                public void onCancelled(@NonNull DatabaseError databaseError) {
                    Toast.makeText(getContext(), databaseError.getMessage(), Toast.LENGTH_SHORT).show();
                }
            });