On navigation item selected not showing fragment with Tab Layout

Question

I am doing a project in which I want to show different fragments depending on where I pick on the navigation view. The problem is that It never shows the fragments that it must show.

The view of the Navigation view is called activity_main and from there you can arrive to the content_main which is the layout used by the fragment manager.

The problem is that the two tabs are not integrated in the toolbar of the mainactivity

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <include
        layout="@layout/app_bar_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />

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

app_bar_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.blindsiot.carlos.blindsiot.MainActivity">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" />

</android.support.design.widget.AppBarLayout>

<include layout="@layout/content_main" />

</android.support.design.widget.CoordinatorLayout>

content_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/content_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.blindsiot.carlos.blindsiot.MainActivity"
    tools:showIn="@layout/app_bar_main">

</RelativeLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {

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

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);

    navigationView.setCheckedItem(R.id.nav_principal);

    /* (. . .) */


    @Override
public boolean onNavigationItemSelected(MenuItem item) {
    int id = item.getItemId();

    Fragment currFragment = null;
    FragmentManager fragmentManager = getSupportFragmentManager();

    if (id == R.id.nav_principal) {
        currFragment = new FastAccessFragment();
    } else if (id == R.id.nav_planning) {
        currFragment = new SignUp();
    } else if (id == R.id.nav_settings) {

    } else if (id == R.id.nav_help) {

    } else if (id == R.id.nav_logout) {
        editor.putBoolean("signedUp", false);
        editor.apply();
        Intent intent = new Intent(this, LoginActivity.class);
        if (intent != null) {
            this.finish();
            startActivity(intent);
        }
    } else if (id == R.id.nav_about) {

    }

    if (currFragment != null) {
        fragmentManager
                .beginTransaction()
                .replace(R.id.content_main, currFragment)
                .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
                .commit();
    }

    setTitle(item.getTitle());


    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);

    return true;
}

FastAccessFragment.java - This is where I am actually and where I don't understand why It does not work

public class FastAccessFragment extends Fragment {

private ViewPager viewPager;
View rootview;
TabLayout tabLayout;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    rootview = inflater.inflate(R.layout.fast_access_fragment, container, false);
    tabLayout = (TabLayout) rootview.findViewById(R.id.tabLayout_fragment);

    tabLayout.addTab(tabLayout.newTab().setText(getString(R.string.action_sign_in_short)).setIcon(R.drawable.tab_login));
    tabLayout.addTab(tabLayout.newTab().setText(getString(R.string.action_sign_up_short)).setIcon(R.drawable.tab_user));
    tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);

    viewPager = (ViewPager) rootview.findViewById(R.id.pager_fragment);

    PagerAdapter pagerAdapter = new PagerAdapter(getChildFragmentManager(), tabLayout.getTabCount());
    viewPager.setAdapter(pagerAdapter);

    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));

    tabLayout.post(new Runnable() {
        @Override
        public void run() {
            tabLayout.setupWithViewPager(viewPager);
            tabLayout.getTabAt(0).setText("test");
            tabLayout.getTabAt(1).setText("test2");
        }
    });

    //Adding onTabSelectedListener to swipe views
    tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            viewPager.setCurrentItem(tab.getPosition());
        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) {

        }

        @Override
        public void onTabReselected(TabLayout.Tab tab) {

        }
    });

    return rootview;
}

public class PagerAdapter extends FragmentStatePagerAdapter {
    int mNumOfTabs;

    public PagerAdapter(FragmentManager fm, int NumOfTabs) {
        super(fm);
        this.mNumOfTabs = NumOfTabs;
    }

    @Override
    public Fragment getItem(int position) {

        switch (position) {
            case 0:
                SignUp tab1 = new SignUp();
                return tab1;
            case 1:
                SignIn tab2 = new SignIn();
                return tab2;
            default:
                return null;
        }
    }

    @Override
    public int getCount() {
        return mNumOfTabs;
    }
}

  }

Answer 1

I also experienced the same problem. I got a fragment inside fragment with TabLayout and ViewPager, inside a Navigation Drawer Activity, in Home menu.

When I clicked another menu and clicked back the Home, my fragment inside the TabLayout never got loaded. The tab is loaded, but not the content.

Took me almost 3 days to figured out what was the cause. And finally I knew that we should use getChildFragmentManager() instead of getActivity().getSupportFragmentManager(). Because what? Because the ViewPager is placed in Fragment, not in Activity. Hope it helps anyone who experiencing the same problem.

This is the WRONG one:

private void setupViewPager(View rootView)
{
    this.mainViewPager = rootView.findViewById(R.id.view_pager_main);

    FragmentManager fragmentManager = this.getActivity().getSupportFragmentManager();

    ViewPagerAdapter adapter = new ViewPagerAdapter(fragmentManager, FragmentPagerAdapter.BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT);

    DataListFragment movieFragment = (DataListFragment) ((MainActivity) this.getActivity()).getTabFragment(0);
    DataListFragment tvFragment = (DataListFragment) ((MainActivity) this.getActivity()).getTabFragment(1);

    adapter.addFragment(movieFragment);
    adapter.addFragment(tvFragment);

    this.mainViewPager.setAdapter(adapter);
}

This is the correct one:

private void setupViewPager(View rootView)
{
    this.mainViewPager = rootView.findViewById(R.id.view_pager_main);

    FragmentManager fragmentManager = this.getChildFragmentManager();

    ViewPagerAdapter adapter = new ViewPagerAdapter(fragmentManager, FragmentPagerAdapter.BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT);

    DataListFragment movieFragment = (DataListFragment) ((MainActivity) this.getActivity()).getTabFragment(0);
    DataListFragment tvFragment = (DataListFragment) ((MainActivity) this.getActivity()).getTabFragment(1);

    adapter.addFragment(movieFragment);
    adapter.addFragment(tvFragment);

    this.mainViewPager.setAdapter(adapter);
}

Answer 2

I have solved it seeing this tutorial: http://www.hermosaprogramacion.com/2015/09/aplicacion-android-con-navigation-drawer-y-tabs/

Thanks anyway!