I am developing an app and I have a problem. I started recording GPS position, but data started to be too much. So I implemented a Button to cancel anything is under "Location" (or under "latitude" and "longitude", it is the same for me). The problem is that nothing seems to be canceled into the database. I am facing this problem for 2 days and I am stuck. This is my DB:

This is the code I used:

public class GalleryFragment extends Fragment {
    private GalleryViewModel galleryViewModel;
    private FragmentGalleryBinding binding;
    DatabaseReference mbase;

    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
        galleryViewModel =
                new ViewModelProvider(this).get(GalleryViewModel.class);

        binding = FragmentGalleryBinding.inflate(inflater, container, false);
        View root = binding.getRoot();
        EditText ET = binding.EditProva;
        Button btn = binding.buttonProva;
        FirebaseDatabase database = FirebaseDatabase.getInstance();
        mbase = FirebaseDatabase.getInstance().getReference();

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                DatabaseReference drTest = FirebaseDatabase.getInstance().getReference();
                drTest.child("Location").addListenerForSingleValueEvent(new ValueEventListener() {
                    @Override
                    public void onDataChange(@NonNull DataSnapshot snapshot) {
                        for(DataSnapshot dataSnapshot:snapshot.getChildren()){
                            dataSnapshot.getRef().setValue(null);
                        }
                    }

                    @Override
                    public void onCancelled(@NonNull DatabaseError error) {
                        Log.w("Errore DB: ", error.getMessage());
                    }
                });
            }
        });

        galleryViewModel.getText().observe(getViewLifecycleOwner(), new Observer<String>() {
            @Override
            public void onChanged(@Nullable String s) {
                //textView.setText(s);
            }
        });
        return root;
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        binding = null;
    }
   }

Before this solution I used that code in the :

                DatabaseReference latRef = database.getReference("Location/latitude");
                latRef.removeValue();
                DatabaseReference longRef = database.getReference("Location/longitude");
                longRef.removeValue();

But neither does this work. I checked out other answers, but nothing helps me.

CodePudding user response：

The problem is that nothing seems to be canceled into the database.

That's happening most likely because you are trying to delete a huge amount of data. If you want to remove everything that exists under the Location node, then you should consider deleting a reasonable number of items one at a time. That can be done on the client, but you can also write a function in Cloud Functions for Firebase, to achieve the exact same result.