public void init(Activity activity) {

    this.activity = activity;
    elementsListFragment = new ElementsListFragment();
    loginFragment = new LoginFragment();
    boardFragment = new BoardFragment();

    CustomFragmentManager.getInstance().init(activity);
  }
 public void goToBoardFragment() {
   CustomFragmentManager.getInstance()
       .replaceFragment(R.id.fragment_container, elementsListFragment, boardFragment, true);
 }
 public void goToMapListFragment(boolean addToBackStack) {
   CustomFragmentManager.getInstance()
       .replaceFragment(
           R.id.fragment_container, loginFragment, elementsListFragment, addToBackStack);
 }
 public void goToLoginFragment() {
   CustomFragmentManager.getInstance().addFragment(R.id.fragment_container, loginFragment);
 }