ResultsActivity.java

...imports... 


public class ResultsActivity extends AppCompatActivity implements
        ResultListFragment.OnListFragmentInteractionListener,
        ResultsMapFragment.OnResultsMapFragmentInteractionListener{

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

    public static final int LIST_FRAGMENT = 1;
    public static final int MAP_FRAGMENT = 2;

    private int CURRENT_FRAGMENT = LIST_FRAGMENT;

    ... fields and such ...

    private ResultListFragment listFragment;
    private ResultsMapFragment mapFragment;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_property_list);
        Toolbar toolbar = (Toolbar) findViewById(R.id.home_list_toolbar);
        setSupportActionBar(toolbar);

         ... other onCreatecode...

        // Check that the activity is using the layout version with
        // the fragment_container FrameLayout
        if (findViewById(R.id.results_fragment_container) != null) {


            // Get Fragment from savedInstanceState
            if (savedInstanceState != null) {
                CURRENT_FRAGMENT = savedInstanceState.getInt("current_fragment");
                listFragment = (ResultListFragment) getSupportFragmentManager().getFragment(savedInstanceState, "listFragment");
                mapFragment = (ResultsMapFragment) getSupportFragmentManager().getFragment(savedInstanceState, "mapFragment");
            }

            // Create a new Fragment to be placed in the activity layout
            listFragment = new ResultListFragment();
            mapFragment = new ResultsMapFragment();

            displayFragment(LIST_FRAGMENT);

        }

    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("current_fragment", CURRENT_FRAGMENT);
        if(listFragment.isAdded()) {
            getSupportFragmentManager().putFragment(outState, "listFragment", listFragment);
        }
        if(mapFragment.isAdded()) {
            getSupportFragmentManager().putFragment(outState, "mapFragment", mapFragment);
        }
    }

    protected void displayFragment(int fragmentFlag) {
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        if(fragmentFlag == MAP_FRAGMENT) {
            CURRENT_FRAGMENT = MAP_FRAGMENT;
            ft.add(R.id.results_fragment_container, mapFragment);
        }
        else {
            CURRENT_FRAGMENT = LIST_FRAGMENT;
            ft.add(R.id.results_fragment_container, listFragment);
        }

        ft.commit();
    }

    protected void replaceFragment(int newFragmentFlag) {

        if(CURRENT_FRAGMENT == newFragmentFlag) {
            return;
        }
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        if(newFragmentFlag == MAP_FRAGMENT) {
            CURRENT_FRAGMENT = MAP_FRAGMENT;
            ft.replace(R.id.results_fragment_container, mapFragment);
        }
        else if (newFragmentFlag == LIST_FRAGMENT) {
            CURRENT_FRAGMENT = LIST_FRAGMENT;
            ft.replace(R.id.results_fragment_container, listFragment);
        }
        ft.commit();

    }

    ... other code that doesnt pertain to the fragment stuff ...

    // callbacks from when menu options to switch to other fragment is called from 
    // within a fragment
    @Override
    public void onMenuMapItemSelected() {
        replaceFragment(MAP_FRAGMENT);
    }

    @Override
    public void onMenuListItemSelected() {
        replaceFragment(LIST_FRAGMENT);
    }

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


    @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();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}