stuff.java

    @Override
    public void changeFragment(String fragment_name) {


        Fragment fragment;
        Class fragmentClass = null;
        if(fragment_name.equals(TeamFragment.TAG_TEAM_FRAGMENT)){
            fragmentClass = TeamFragment.class;

            Log.d("HW2", "team fragment selected");
        }
        else if(fragment_name.equals(MyStepsFragment.TAG_MY_STEPS_FRAGMENT)){
            fragmentClass = MyStepsFragment.class;

            Log.d("HW2", "team fragment selected");
        }
        else if(fragment_name.equals(TeamsRankFragment.TAG_TEAM_RANK_FRAGMENT)){
            fragmentClass = TeamsRankFragment.class;

            Log.d("HW2", "team rank fragment selected");
        }

        try {
            if (fragmentClass != null) {
                fragment = (Fragment) fragmentClass.newInstance();



                FragmentTransaction ft= fragmentManager.beginTransaction();


                Log.d("hello", fragment_name); //dashboard_fragment
                Log.d("hello2", ((RetainedFragmentInteraction)taskFragment).getActiveFragmentTag()); //home_fragment
                ft.replace(R.id.frame, fragment,
                        ((RetainedFragmentInteraction)taskFragment).getActiveFragmentTag());
                ft.addToBackStack(null);
                ft.commit();


            }
        } catch (Exception e) {
            e.printStackTrace();
        }