Adding checkmarks in a leaderboard

Question

Hi! I'am trying to display a leaderboard where you can add or remove friends. It works fine when I sign up a new user and then add or remove fiends but when I restart the app and navigate to the leaderboard fragment, it crashes.

.invisible{

visivility:hidden;
  public class LeaderboardFragment extends ListFragment {

    public static final String TAG = LeaderboardFragment.class.getSimpleName();
    protected List<ParseUser> mUsers;
    protected List<ParseUser> mFriends;


    protected ParseRelation<ParseUser> mFriendsRelation; //
    protected ListView mListView; //
    protected ParseUser mCurrentUser; //
    protected OnItemClickListener mOnItemClickListener;



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

        mListView = (ListView) rootView.findViewById(android.R.id.list);

        mListView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);

        TextView emptyTextView = (TextView)rootView.findViewById(android.R.id.empty);
        mListView.setEmptyView(emptyTextView);

        return rootView;
    }

    @Override
    public void onResume() {
        super.onResume();

        mCurrentUser = ParseUser.getCurrentUser();
        mFriendsRelation = mCurrentUser.getRelation(ParseConstants.KEY_FRIENDS_RELATION);


        ParseQuery<ParseUser> query = ParseUser.getQuery();
        query.orderByDescending(ParseConstants.KEY_SCORE);
//      query.addAscendingOrder(ParseConstants.KEY_USERNAME);
        query.setLimit(100);
        query.findInBackground(new FindCallback<ParseUser>() {

            @Override
            public void done(List<ParseUser> users, ParseException e) {
                if (e == null) {
                    mUsers = users;
                    String[] usernames = new String[mUsers.size()];
                    int i = 0;
                    for (ParseUser user : mUsers) {
                        usernames[i] = user.getUsername();
                        i++;
                    }
                    if (mListView.getAdapter() == null) {
                        PlayerAdapter adapter = new PlayerAdapter(getListView().getContext(), mUsers);

                        setListAdapter(adapter);
                    } 
                    else {
                        ((PlayerAdapter) mListView.getAdapter()).addAll(mUsers);
                    }
                    addFriendCheckmarks();

                } 
                else {
                    Log.e(TAG, e.getMessage());
                    AlertDialog.Builder builder = new AlertDialog.Builder(
                            getActivity());
                    builder.setMessage(e.getMessage())
                            .setTitle(R.string.error_title)
                            .setPositiveButton(android.R.string.ok, null);
                    AlertDialog dialog = builder.create();
                    dialog.show();
                }

            }
        });
    }



    @Override
    public void onListItemClick(ListView l, View v, int position, long id) {



        super.onListItemClick(l, v, position, id);
        if (mListView.isItemChecked(position)){
            mFriendsRelation.add(mUsers.get(position));


        }
        else{
            mFriendsRelation.remove(mUsers.get(position));

        }

        mCurrentUser.saveInBackground(new SaveCallback() {
            @Override
            public void done(ParseException e) {
                if (e != null) {
                    Log.e(TAG, e.getMessage());
                }
            }
        });

    }




    private void addFriendCheckmarks() {
        mFriendsRelation.getQuery().findInBackground(new FindCallback<ParseUser>() {
            @Override
            public void done(List<ParseUser> friends, ParseException e) {
                if (e == null) {
                    // list returned - look for a match
                    for (int i = 0; i < mUsers.size(); i++) {
                        ParseUser user = mUsers.get(i);

                        for (ParseUser friend : friends) {
                            if (friend.getObjectId().equals(user.getObjectId())) {
                                mListView.setItemChecked(i, true);
                            }
                        }
                    }
                }
                else {
                    Log.e(TAG, e.getMessage());
                }
            }
        });
    }



}
}

I think that the main problem is when I receive the users from parse i the addingcheckmarks blog of code.

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Adding checkmarks in a leaderboard

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Harry James

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Joan Marc Sanahuja

Joan Marc Sanahuja

Joan Marc Sanahuja

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