Why am I not seeing my friends when I am clicking edit friends?

public static final String TAG = EditFriendsActivity.class.getSimpleName();

protected List<ParseUser> mUsers;
protected ParseRelation <ParseUser> mFriendsRelation;
protected ParseUser mCurrentUser;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
    setContentView(R.layout.activity_edit_friends);

    getListView().setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.edit_friends, menu);


    return true;
}


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

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

    setProgressBarIndeterminate(true);

    ParseQuery<ParseUser> query = ParseUser.getQuery();
    query.orderByAscending(ParseConstants.KEY_USERNAME);

    query.setLimit(1000);
    query.findInBackground(new FindCallback<ParseUser>() {

        @Override
        public void done(List<ParseUser> users, ParseException e) {
            setProgressBarIndeterminate(false);

            if(e == null){
                //success
                mUsers = users;
                String[] usernames = new String[mUsers.size()];
                int i = 0;
                for (ParseUser user : mUsers){
                    usernames[i] = user.getUsername();
                    i++;
                }
                ArrayAdapter<String> adapter = new ArrayAdapter<>(EditFriendsActivity.this, 
                        android.R.layout.simple_list_item_checked, usernames);
                        setListAdapter(adapter);

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

        }
    });
}


@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);

    if(getListView().isItemChecked(position)){
        mFriendsRelation.add(mUsers.get(position));
        mCurrentUser.saveInBackground(new SaveCallback() {

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

            }
        });
    }
    else{
        //Remove them
    }

}
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()));
                        getListView().setItemChecked(i, true);
                    }
                }
            }
            else{
                Log.e(TAG, e.getMessage());
            }

        }
    });
}