EventFragment.java

public class PastEventFragment extends Fragment {

    private static final String TAG = PastEventFragment.class.getSimpleName();
    public static final String MARATHON_EVENT_DATABASE = "event";

    private DatabaseReference mDatabase;
    private List<Event> mEventList;
    private Query mEventsQuery;
  
    private Context mContext;

    public PastEventFragment() {
    }

    // TODO: Customize parameter initialization
    @SuppressWarnings("unused")
    public static PastEventFragment newInstance() {
        PastEventFragment fragment = new PastEventFragment();
        Bundle args = new Bundle();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setHasOptionsMenu(true);

        mDatabase = FirebaseDatabase.getInstance().getReference(MARATHON_EVENT_DATABASE);

        mEventsQuery = mDatabase.child(DateHelper.getCurrentYear()).orderByChild("date").startAt(DateHelper.getCurrentDate());

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        final View view = inflater.inflate(R.layout.fragment_past_event_list, container, false);
 

        if(savedInstanceState == null) {
            addFirebaseEventListener();
        }

        return view;
    }


    private void addFirebaseEventListener() {

        mEventsQuery.addValueEventListener(new ValueEventListener() {

            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                // This method is called once with the initial value and again
                // whenever data at this location is updated.
                mEventList = new ArrayList<Event>();

                if(dataSnapshot.exists()) {
                    for (DataSnapshot eventSnapshot : dataSnapshot.getChildren()) {

                        Event event = eventSnapshot.getValue(Event.class);
                        mEventList.add(event);
                       ;

                    }
                    // Set Adapter

                }

            }

            @Override
            public void onCancelled(DatabaseError error) {
                Log.w(TAG, "Failed to read value.", error.toException());
            }


        });
    }

}