Back navigation in Android navigation drawer won't change selected item

Question

I'm developing on Android for only a few days now and I like it a lot, but right now I'm having a problem I really can't find the solution for.

Actually I can find all kind of posts on the internet about this issue, but none of them worked for me...Most certain I'm doing something wrong, but I just don't know what. So here I am to call for your help!

I'm building a sports app for our local sports club and I'm using a Navigation Drawer to switch pages (fragments). On these fragments I show blog posts, scorings, team info, etc. Now when I open the app everything goes well, navigating through the fragments using the Navigation Drawer goes well, but when I try to turn back to the previous fragment, the app only partly goes like I want. If I'm pushing the back-button on my phone, the application indeed shows the previously shown fragment, but the selected item in the Navigation Drawer and the title of the page won't change.

Please take a look at my code and help me out, it would be great!!

MainActivity.java:

import android.app.Activity;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.ArrayAdapter;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity implements NavigationDrawerFragment.NavigationDrawerCallbacks {

    // Fragment managing the behaviors, interactions and presentation of the navigation drawer.
    private NavigationDrawerFragment mNavigationDrawerFragment;

    // Used to store the last screen title. For use in {@link #restoreActionBar()}.
    private CharSequence mTitle;

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

        mNavigationDrawerFragment = (NavigationDrawerFragment)getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
        mTitle = getTitle();

        // Set up the navigation drawer.
        mNavigationDrawerFragment.setUp(R.id.navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout));
    }

    @Override
    public void onNavigationDrawerItemSelected(int position) {
        // update the main content by replacing fragments
        FragmentManager fragmentManager = getSupportFragmentManager();
        switch (position + 1) {
            case 1:
                fragmentManager.beginTransaction().replace(R.id.container, PlaceholderFragment.newInstance(position + 1)).commit();
                break;
            case 2:
                fragmentManager.beginTransaction().replace(R.id.container, FragmentNieuws.newInstance(position + 1)).addToBackStack(null).commit();
                break;
            case 3:
                fragmentManager.beginTransaction().replace(R.id.container, FragmentUitslagen.newInstance(position + 1)).addToBackStack(null).commit();
                break;
            case 4:
                fragmentManager.beginTransaction().replace(R.id.container, FragmentProgramma.newInstance(position + 1)).addToBackStack(null).commit();
                break;
            case 5:
                fragmentManager.beginTransaction().replace(R.id.container, FragmentMijnteam.newInstance(position + 1)).addToBackStack(null).commit();
                break;
        }
    }

    public void onSectionAttached(int number) {
        // update the title by replacing fragments
        switch (number) {
            case 1:
                mTitle = getString(R.string.title_section1);
                break;
            case 2:
                mTitle = getString(R.string.title_section2);
                break;
            case 3:
                mTitle = getString(R.string.title_section3);
                break;
            case 4:
                mTitle = getString(R.string.title_section4);
                break;
            case 5:
                mTitle = getString(R.string.title_section5);
                break;
        }
    }

    public void restoreActionBar() {
        ActionBar actionBar = getSupportActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
        actionBar.setDisplayShowTitleEnabled(true);
        actionBar.setTitle(mTitle);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        if (!mNavigationDrawerFragment.isDrawerOpen()) {
            // Only show items in the action bar relevant to this screen
            // if the drawer is not showing. Otherwise, let the drawer
            // decide what to show in the action bar.
            getMenuInflater().inflate(R.menu.main, menu);
            restoreActionBar();
            return true;
        }
        return super.onCreateOptionsMenu(menu);
    }

    @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);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        private static final String ARG_SECTION_NUMBER = "section_number";

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        public PlaceholderFragment() {

        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            return rootView;
        }

        @Override
        public void onAttach(Activity activity) {
            super.onAttach(activity);
            ((MainActivity) activity).onSectionAttached(getArguments().getInt(ARG_SECTION_NUMBER));
        }
    }
}

NavigationDrawerFragment.java:

import android.support.v7.app.ActionBarActivity;
import android.app.Activity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

/**
 * Fragment used for managing interactions for and presentation of a navigation drawer.
 * See the <a href="https://developer.android.com/design/patterns/navigation-drawer.html#Interaction">
 * design guidelines</a> for a complete explanation of the behaviors implemented here.
 */
public class NavigationDrawerFragment extends Fragment {

    /**
     * Remember the position of the selected item.
     */
    private static final String STATE_SELECTED_POSITION = "selected_navigation_drawer_position";

    /**
     * Per the design guidelines, you should show the drawer on launch until the user manually
     * expands it. This shared preference tracks this.
     */
    private static final String PREF_USER_LEARNED_DRAWER = "navigation_drawer_learned";

    /**
     * A pointer to the current callbacks instance (the Activity).
     */
    private NavigationDrawerCallbacks mCallbacks;

    /**
     * Helper component that ties the action bar to the navigation drawer.
     */
    private ActionBarDrawerToggle mDrawerToggle;

    private DrawerLayout mDrawerLayout;
    private ListView mDrawerListView;
    private View mFragmentContainerView;

    private int mCurrentSelectedPosition = 0;
    private boolean mFromSavedInstanceState;
    private boolean mUserLearnedDrawer;

    public NavigationDrawerFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Read in the flag indicating whether or not the user has demonstrated awareness of the
        // drawer. See PREF_USER_LEARNED_DRAWER for details.
        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity());
        mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false);

        if (savedInstanceState != null) {
            mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
            mFromSavedInstanceState = true;
        }

        // Select either the default item (0) or the last selected item.
        selectItem(mCurrentSelectedPosition);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        // Indicate that this fragment would like to influence the set of actions in the action bar.
        setHasOptionsMenu(true);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        mDrawerListView = (ListView) inflater.inflate(
                R.layout.fragment_navigation_drawer, container, false);
        mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                selectItem(position);

            }
        });
        mDrawerListView.setAdapter(new ArrayAdapter<String>(
                getActionBar().getThemedContext(),
                android.R.layout.simple_list_item_activated_1,
                android.R.id.text1,
                new String[]{
                        getString(R.string.title_section1),
                        getString(R.string.title_section2),
                        getString(R.string.title_section3),
                        getString(R.string.title_section4),
                        getString(R.string.title_section5),
                }));
        mDrawerListView.setItemChecked(mCurrentSelectedPosition, true);
        return mDrawerListView;
    }

    public boolean isDrawerOpen() {
        return mDrawerLayout != null && mDrawerLayout.isDrawerOpen(mFragmentContainerView);
    }

    /**
     * Users of this fragment must call this method to set up the navigation drawer interactions.
     *
     * @param fragmentId   The android:id of this fragment in its activity's layout.
     * @param drawerLayout The DrawerLayout containing this fragment's UI.
     */
    public void setUp(int fragmentId, DrawerLayout drawerLayout) {
        mFragmentContainerView = getActivity().findViewById(fragmentId);
        mDrawerLayout = drawerLayout;

        // set a custom shadow that overlays the main content when the drawer opens
        mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
        // set up the drawer's list view with items and click listener

        ActionBar actionBar = getActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setHomeButtonEnabled(true);

        // ActionBarDrawerToggle ties together the the proper interactions
        // between the navigation drawer and the action bar app icon.
        mDrawerToggle = new ActionBarDrawerToggle(
                getActivity(),                    /* host Activity */
                mDrawerLayout,                    /* DrawerLayout object */
                R.drawable.ic_drawer,             /* nav drawer image to replace 'Up' caret */
                R.string.navigation_drawer_open,  /* "open drawer" description for accessibility */
                R.string.navigation_drawer_close  /* "close drawer" description for accessibility */
        ) {
            @Override
            public void onDrawerClosed(View drawerView) {
                super.onDrawerClosed(drawerView);
                if (!isAdded()) {
                    return;
                }

                getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
            }

            @Override
            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);
                if (!isAdded()) {
                    return;
                }

                if (!mUserLearnedDrawer) {
                    // The user manually opened the drawer; store this flag to prevent auto-showing
                    // the navigation drawer automatically in the future.
                    mUserLearnedDrawer = true;
                    SharedPreferences sp = PreferenceManager
                            .getDefaultSharedPreferences(getActivity());
                    sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true).apply();
                }

                getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
            }
        };

        // If the user hasn't 'learned' about the drawer, open it to introduce them to the drawer,
        // per the navigation drawer design guidelines.
        if (!mUserLearnedDrawer && !mFromSavedInstanceState) {
            mDrawerLayout.openDrawer(mFragmentContainerView);
        }

        // Defer code dependent on restoration of previous instance state.
        mDrawerLayout.post(new Runnable() {
            @Override
            public void run() {
                mDrawerToggle.syncState();
            }
        });

        mDrawerLayout.setDrawerListener(mDrawerToggle);
    }

    private void selectItem(int position) {
        mCurrentSelectedPosition = position;
        if (mDrawerListView != null) {
            mDrawerListView.setItemChecked(position, true);
        }
        if (mDrawerLayout != null) {
            mDrawerLayout.closeDrawer(mFragmentContainerView);
        }
        if (mCallbacks != null) {
            mCallbacks.onNavigationDrawerItemSelected(position);
        }
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            mCallbacks = (NavigationDrawerCallbacks) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException("Activity must implement NavigationDrawerCallbacks.");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mCallbacks = null;
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition);
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        // Forward the new configuration the drawer toggle component.
        mDrawerToggle.onConfigurationChanged(newConfig);
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        // If the drawer is open, show the global app actions in the action bar. See also
        // showGlobalContextActionBar, which controls the top-left area of the action bar.
        if (mDrawerLayout != null && isDrawerOpen()) {
            inflater.inflate(R.menu.global, menu);
            showGlobalContextActionBar();
        }
        super.onCreateOptionsMenu(menu, inflater);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (mDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }

        if (item.getItemId() == R.id.action_example) {
            Toast.makeText(getActivity(), "Example action.", Toast.LENGTH_SHORT).show();
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    /**
     * Per the navigation drawer design guidelines, updates the action bar to show the global app
     * 'context', rather than just what's in the current screen.
     */
    private void showGlobalContextActionBar() {
        ActionBar actionBar = getActionBar();
        actionBar.setDisplayShowTitleEnabled(true);
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
        actionBar.setTitle(R.string.app_name);
    }

    private ActionBar getActionBar() {
        return ((ActionBarActivity) getActivity()).getSupportActionBar();
    }

    /**
     * Callbacks interface that all activities using this fragment must implement.
     */
    public static interface NavigationDrawerCallbacks {
        /**
         * Called when an item in the navigation drawer is selected.
         */
        void onNavigationDrawerItemSelected(int position);

    }

}

FragmentNieuws.java (one of the fragments I use):

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebView;
import android.webkit.WebViewClient;

public class FragmentNieuws extends Fragment {
    // Definieer de webviewer om webpagina's te kunnen bekijken in de app
    WebView myWebView;

    private static final String ARG_SECTION_NUMBER = "section_number";

    public static FragmentNieuws newInstance(int sectionNumber) {
        FragmentNieuws fragment = new FragmentNieuws();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    public FragmentNieuws() {

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_nieuws, container, false);

        // Open de URL voor deze pagina in de app
        myWebView = (WebView) rootView.findViewById(R.id.webviewnieuws);
        myWebView.setWebViewClient(new WebViewClient());
        myWebView.loadUrl("http://www.url.com");

        return rootView;
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        ((MainActivity) activity).onSectionAttached(getArguments().getInt(ARG_SECTION_NUMBER));
    }

activity_main.xml:

<!-- A DrawerLayout is intended to be used as the top-level content view using match_parent for both width and height to consume the full space available. -->
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:id="@+id/drawer_layout"
    android:layout_width="match_parent" android:layout_height="match_parent"
    tools:context=".MainActivity">

    <!-- As the main content view, the view below consumes the entire
         space available using match_parent in both dimensions. -->
    <FrameLayout android:id="@+id/container" android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <!-- android:layout_gravity="start" tells DrawerLayout to treat
         this as a sliding drawer on the left side for left-to-right
         languages and on the right side for right-to-left languages.
         If you're not building against API 17 or higher, use
         android:layout_gravity="left" instead. -->
    <!-- The drawer is given a fixed width in dp and extends the full height of
         the container. -->
    <fragment android:id="@+id/navigation_drawer"
        android:layout_width="@dimen/navigation_drawer_width" android:layout_height="match_parent"
        android:layout_gravity="start"
        android:name=".NavigationDrawerFragment"
        tools:layout="@layout/fragment_navigation_drawer" />

</android.support.v4.widget.DrawerLayout>

Answer 1

I believe it is as follows.

The title that you get with mTitle = getTitle(); in the onCreate of the Activity is set in the AndroidManifest.xml (and the strings.xml subsequently):

<activity
     android:name=".SomeActivity"
     android:label="@string/app_name"

When you select the NavigationDrawer, and have not clicked an item, this title is shown:

private void showGlobalContextActionBar() { 
    actionBar.setTitle(R.string.app_name);

When an item is selected it shows the name of that item, via the call to onSectionAttached and then restoreActionBar which sets the Title. The default way the title in the ActionBar is chosen is to show the title of the last item of the NavigationDrawer (not the title of the Fragment ). However if you click back, you might want to check which methods are called. My guess is that restoreActionBar is not, such that the title does not update.

You could therefore do the following override:

@Override
    public void onBackPressed() {
        super.onBackPressed();
        restoreActionBar();
    }