从片段访问和使用活动导航抽屉

Question

Is there a way possible to access the navigation drawer I created in my activity from my fragment? I also want to be able to use the back pressed feature. My activity is launched on handsets and my fragment is launched on tablets.

activity class

public class BakerlooHDNActivity extends AppCompatActivity {

    private Drawer result = null;

    @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);
        }

        // 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)
                .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) {
             result.closeDrawer();
        }
    };

    private AccountHeader headerResult = null;
    private Drawer result = null;

    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);

        super.onCreate(savedInstanceState);
        return v;
    }

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

        super.onActivityCreated(savedInstanceState);
    }
}

Answer 1

I would never have a fragment access the drawer directly. Instead I would call the Activity via a callback method from the Fragment and then access the drawer.

After re-reading your question I suggest the following:

• You Activity is already closing the drawer so no need to do it again in the fragment.
• You should have 2 fragments, one for tablet and one for phone

If you still need to communicate with the Fragment do this:

public void onBackPressed() {
    if (result.isDrawerOpen()) {
        result.closeDrawer();
        getSupportFragmentManager().findFragmentByTag("FRAGMENT_TAG").doSomething();
    } else {
        super.onBackPressed();
    }
}

In your Fragment add this:

public void doSomething() {
    // Do it here
}

Answer 2

My suggestion is basically to create a public method in the fragment. And the activity calls the public method passing the drawer object. Simple really. This has the effect of passing the drawer by reference.

Code suggestion. In BakerlooHDNActivity class:

AccountHeader headerResult;

if (savedInstanceState == null) {
   FragmentBakerlooHDN myFragment = new FragmentBakerlooHDN();
   myFragment.setDrawer(headerResult);
}

In FragmentBakerlooHDN class:

private AccountHeader myDrawer;

public void setDrawer(final AccountHeader drawer) {
   this.myDrawer = drawer;
}

Notes:

• You may pass the object headerResult onto FragmentBakerlooHDN constructor but that is normally not done due to fragment lifecycle, I believe.
• For now, you may call the public setDrawer immediately after creating new instance of the fragment. But there may be issues with UI and fragment lifecycle.
• If you modify contents of the drawer, either do it in activity or fragment, not both. Again, this solution is passing the drawer object by reference. So it is powerful enough to be dangerous. Another method would be to use the technique of using callback/listener like what Sweder has said.
• Object myDrawer is declared as AccountHeader instead of AccountHeaderBuilder.

Answer 3

My suggestion is use method onBackPressed in Activity. I updated source code of my tutorial about NavigationDrawer ( https://github.com/AlexZhukovich/NavigationDrawerTutorial ). I hope it's help you. I used NavigationDrawer from com.android.support:design in this tutorial.

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

For me it's work in tablet and phone. (Nexus devices).

I created simple activity with fragment for you. This activity shows 2 fragment, but after click to back, delete second fragment.

    public class TestActivity extends AppCompatActivity {

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

        getSupportFragmentManager().beginTransaction().add(R.id.container, new DummyFragment(), "TEST").commit();
        getSupportFragmentManager().beginTransaction().add(R.id.container2, new DummyFragment(), "TEST2").commit();
    }

    @Override
    public void onBackPressed() {
        if (getSupportFragmentManager().findFragmentByTag("TEST2") != null && getSupportFragmentManager().findFragmentByTag("TEST2").isVisible()) {
            getSupportFragmentManager().beginTransaction().remove(getSupportFragmentManager().findFragmentByTag("TEST2")).commit();
        } else {
            super.onBackPressed();
        }
    }

    private class DummyFragment extends Fragment {

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