how to display list of data from firebase realtime database code example

Example 1: firebase search into every child

ref.child('users').orderByChild('name').equalTo('John Doe').on("value", function(snapshot) {
    console.log(snapshot.val());
    snapshot.forEach(function(data) {
        console.log(data.key);
    });
});

Example 2: display arraylist messages realtime database

dbref.addValueEventListener(new com.google.firebase.database.ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {

                ArrayList list = new ArrayList<>();
                list.clear();

                for(DataSnapshot ds :dataSnapshot.getChildren()) {
                    Score Result = ds.getValue(Score.class);
                    String userId = String.valueOf(Result.getUserId());
                    String score = String.valueOf(Result.getScore());
                    list.add(userId);
                    list.add(score);

                }
                adapter = new ArrayAdapter<>(getActivity(), android.R.layout.simple_list_item_1, list);
                LvRanking.setAdapter(adapter);
            }