Back press feature for navigation drawer not working

Question

I'm trying to implement the back press feature for a fragment and activity regarding the navigation drawer but it's not working. Does anyone know what I'm doing wrong / what is missing and what needs to be done in order to fix this?

activity class

public class BakerlooHDNActivity extends AppCompatActivity {

    //save our header or result
    private Drawer result = null;

    // Declaring Views and Variables
    ViewPager pager;
    BakerlooHDNViewPagerAdapter adapter;
    BakerlooHDNSlidingTabLayout bakerloohdntabs;
    int Numboftabs = 2;

    private int getFactorColor(int color, float factor) {
        float[] hsv = new float[3];
        Color.colorToHSV(color, hsv);
        hsv[2] *= factor;
        color = Color.HSVToColor(hsv);
        return color;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bakerloo_hdn);


        final String actionBarColor = "#B36305";

        Toolbar mToolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(mToolbar);

        if(getSupportActionBar()!=null) {
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
            getSupportActionBar().setDisplayShowHomeEnabled(false);
            getSupportActionBar().setTitle(Html.fromHtml("<font color='#FFFFFF'>" + getResources().getString(R.string.hdn) + "</font>"));
            getSupportActionBar().setSubtitle(Html.fromHtml("<font color='#FFFFFF'>" + getResources().getString(R.string.zone_3) + "</font>"));

            final Drawable upArrow = ContextCompat.getDrawable(this, R.drawable.abc_ic_ab_back_mtrl_am_alpha);
            upArrow.setColorFilter(getResources().getColor(R.color.white), PorterDuff.Mode.SRC_ATOP);
            getSupportActionBar().setHomeAsUpIndicator(upArrow);
        }

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            Window window = getWindow();
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            getWindow().setStatusBarColor(getFactorColor(Color.parseColor(actionBarColor), 0.8f));
        }

        // start of navigation drawer
        headerResult = new AccountHeaderBuilder()
                .withActivity(getActivity())
                .withCompactStyle(true)
                .withHeaderBackground(R.color.bakerloo)
                .withProfileImagesVisible(false)
                .withTextColor(Color.parseColor("#FFFFFF"))
                .withSelectionListEnabled(false)

                .addProfiles(
                        new ProfileDrawerItem().withName(getString(R.string.hdn)).withEmail(getString(R.string.hello_world))
                )
                .build();

        result = new DrawerBuilder()
                .withActivity(getActivity())
                .withAccountHeader(headerResult)
                .withTranslucentStatusBar(false)
                .withActionBarDrawerToggle(false)
                .withSelectedItem(-1)
                .addDrawerItems(
                        new PrimaryDrawerItem().withName(R.string.hello_world).withIdentifier(1).withCheckable(false)
                )
                .build();
        // end of navigation drawer
    }


    @Override
    public void onBackPressed() {
        if (result.isDrawerOpen()) {
            result.closeDrawer();
        } else {
            super.onBackPressed();
        }
        LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(new Intent("BACKPRESSED_TAG"));
    }
}

fragment class

public class FragmentBakerlooHDN extends android.support.v4.app.Fragment {

    public FragmentBakerlooHDN() {
        // Required empty constructor
    }

    BroadcastReceiver onNotice = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            // do stuff when back in activity is pressed
             result.closeDrawer();
        }
    };

    // Declaring navigation drawer
    private AccountHeader headerResult = null;
    private Drawer result = null;

    /**
     * Whether or not the activity is in two-pane mode, i.e. running on a tablet
     * device.
     */
    private boolean mTwoPane;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        LocalBroadcastManager.getInstance(getActivity()).registerReceiver(onNotice, new IntentFilter("BACKPRESSED_TAG"));

        super.onCreate(savedInstanceState);
    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_bakerloo_hdn, container, false);

        // start of navigation drawer
        headerResult = new AccountHeaderBuilder()
                .withActivity(getActivity())
                .withCompactStyle(true)
                .withHeaderBackground(R.color.bakerloo)
                .withProfileImagesVisible(false)
                .withTextColor(Color.parseColor("#FFFFFF"))
                .withSelectionListEnabled(false)

                .addProfiles(
                        new ProfileDrawerItem().withName(getString(R.string.hdn)).withEmail(getString(R.string.hello_world))
                )
                .build();

        result = new DrawerBuilder()
                .withActivity(getActivity())
                .withAccountHeader(headerResult)
                .withTranslucentStatusBar(false)
                .withActionBarDrawerToggle(false)
                .withSelectedItem(-1)
                .addDrawerItems(
                        new PrimaryDrawerItem().withName(R.string.hello_world).withIdentifier(1).withCheckable(false)
                )
                .build();
        // end of navigation drawer


        super.onCreate(savedInstanceState);
        return v;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        View v = getView();

        super.onActivityCreated(savedInstanceState);
    }
}

Answer 1

try this:

    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;

    @Override
    public void onCreate() {
        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        mDrawerList = (ListView) findViewById(R.id.navdrawer);
    }

    @Override
    public void onBackPressed() {
        if(mDrawerLayout.isDrawerOpen(mDrawerList)) mDrawerLayout.closeDrawer(mDrawerList);
        else super.onBackPressed();
    }

EDIT:

You can use LocalBroadcastManager to update fragment when in activity back is pressed:

in fragment add new BroadcastReceiver() Instance:

 BroadcastReceiver onNotice = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        // do stuff when back in activity is pressed
        // headerResult.closeDrawer();
    }
};

and register it with tag in onCreate method:

LocalBroadcastManager.getInstance(this).registerReceiver(onNotice,
            new IntentFilter("BACKPRESSED_TAG"));

Then, in Activity OnBackPressed method call broadcast:

LocalBroadcastManager.getInstance(context).sendBroadcast(new Intent("BACKPRESSED_TAG"));

Answer 2

Do you have a reference inside your code to the interface? Looks like you're calling that interface directly hence the errors. Try renaming that method too. It might be conflicting with the super class's onBackPressed method.

Answer 3

Your problem is that your interface is named exactly as the property you are trying to use.

Rename it and use a instance.

@Override
public void onBackPressed() {
    OnBackPressedListener instance = getSettedListener();
    if (result.isDrawerOpen()) {
        result.closeDrawer();
    } else {
        return instance.onBackPressed();
    }
}

public interface OnBackPressedListener {
    boolean onBackPressed();
}

This code would compile if you also implement the method getSettedListener on your code (that could be like the following):

    public OnBackPressedListener getSettedListener() {
           return new OnBackPressedListener(){
                   boolean onBackPressed(){
                          if(shouldConsumeBack)
                               return consumeBack();
                          else return false;
                     };
         }
}

But this code could return the Fragment that does implements the method.