How do I retrieve a list of all children in a Firebase realtime database?

Question

The structure of my Firebase database is shown below. I want to make a list of all the Rooms in Android Studio. In other words, I need an array of [Room1, Room2, ...] for use in a spinner. How can I do this?

Answer 1

What you can do is loop over all the children of your database and add them to an ArrayList and then use an array adapter to display the list.

What I am saying, looks something like this in code:

rootRef.child("Rooms").addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
       for (DataSnapshot ds : dataSnapshot.getChildren()) {
            array.add(ds.child("Users").child("UserID").getValue(String.class));
        }

        ArrayAdapter adapter = new ArrayAdapter(YourActivity.this, android.R.layout.simple_list_item_1, array);
        listView.setAdapter(adapter);
    }

    @Override
    public void onCancelled(@NonNull DatabaseError databaseError) {
        // Do something for errors too
    }
});