Implementing proper back navigation and home button handling using Toolbar in Android

Question

I am using a single activity and multiple fragments(screenshot attached) within the same activity to provide a seamless navigation. But after implementing the latest toolbar and

Answer 1

Try something like this:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    if (getSupportActionBar()!=null) {
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

    drawer = (DrawerLayout) findViewById(R.id.drawer_layout);

    final ActionBarDrawerToggle drawerToggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.addDrawerListener(drawerToggle);
    drawerToggle.syncState();

    final View.OnClickListener originalToolbarListener = drawerToggle.getToolbarNavigationClickListener();

    final View.OnClickListener navigationBackPressListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getFragmentManager().popBackStack();
        }
    };

    getFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
        @Override
        public void onBackStackChanged() {
            if (getFragmentManager().getBackStackEntryCount() > 0) {
                drawerToggle.setDrawerIndicatorEnabled(false);
                drawerToggle.setToolbarNavigationClickListener(navigationBackPressListener);
            } else {
                drawerToggle.setDrawerIndicatorEnabled(true);
                drawerToggle.setToolbarNavigationClickListener(originalToolbarListener);
            }
        }
    });

    // Though below steps are not related but I have included to show drawer close on Navigation Item click. 

    navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(MenuItem item) {
            int id = item.getItemId();
            /**
             * handle item clicks using id
             */
            drawer.closeDrawer(GravityCompat.START);
            return true;
        }
    });
}

Handle the drawer state onBackPressed:

@Override
public void onBackPressed() {
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}

To reload previous fragment on back press, always add the fragment transaction to back stack like this:

FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
SomeFragment fragmentToBeLoaded = new SomeFragment();
fragmentTransaction.replace(R.id.fragment_container, fragmentToBeLoaded,
                fragmentToBeLoaded.getName());
fragmentTransaction.addToBackStack(fragmentToBeLoaded.getName());
fragmentTransaction.commit();

To dynamically change the page title, you can call this from every Fragments onStart or onResume method:

@Override
public void onStart() {
   super.onStart();
   getActivity().setTitle("Title for fragment");
}

Note: I have considered standard layout declaration and thus I have not included any layouts.