Android - Multiple fragments in ONE tab

Question

I searched a lot in the web about the possibility to have multiple fragments in one action bar tab.

This question comes closest to my needs but the code is not working.

Is there another possibility to include multiple fragments in one tab?

---

This is the StartActivity

public class StartActivity extends FragmentActivity implements ActionBar.TabListener {

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

        // Set up the action bar.
        final ActionBar actionBar = getActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        actionBar.addTab(
              actionBar.newTab()
             .setText("Karte")
              .setTabListener(new MapFragmentListener(this)));

    }

The corresponding layout acticity_start contains two frame layouts for the two fragments that will be placed in the tab.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >  

    <FrameLayout
        android:id="@+id/fragment_map"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>
    <FrameLayout
        android:id="@+id/fragment_realtime"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

The TabListener looks like this:

private class TabListener implements ActionBar.TabListener {

        private static final String fragment1_tag = "fragment1_tag";
        private static final String fragment2_tag = "fragment2_tag";

        private FragmentActivity activity;
        private RealtimeFragment fragment1;
        private RealtimeFragment fragment2;

        public TabListener(FragmentActivity activity) {

            this.activity = activity;

            android.support.v4.app.FragmentTransaction ft = activity.getSupportFragmentManager().beginTransaction();

            fragment1 = (RealtimeFragment) activity.getSupportFragmentManager().findFragmentByTag(fragment1_tag);
            if (fragment1 != null && !fragment1.isDetached()) {
                ft.detach(fragment1);
            }

            fragment2 = (RealtimeFragment) activity.getSupportFragmentManager().findFragmentByTag(fragment2_tag);
            if (fragment2 != null && !fragment2.isDetached()) {
                ft.detach(fragment2);
            }

            ft.commit();
        }

        @Override
        public void onTabReselected(Tab tab, FragmentTransaction ft) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onTabSelected(Tab tab, FragmentTransaction ft) {

            android.support.v4.app.FragmentTransaction fragmentTransaction = activity.getSupportFragmentManager().beginTransaction();

            if(fragment1 == null) {
                fragment1 = new RealtimeFragment();
                fragmentTransaction.add(R.id.fragment_map, fragment1, fragment1_tag);
            } else {
                fragmentTransaction.attach(fragment1);
            }


            if(fragment2 == null) {
                fragment2 = new RealtimeFragment();
                fragmentTransaction.add(R.id.fragment_realtime, fragment2, fragment2_tag);
            } else {
                fragmentTransaction.attach(fragment2);
            }


            fragmentTransaction.commit();

        }

        @Override
        public void onTabUnselected(Tab tab, FragmentTransaction ft) {

            android.support.v4.app.FragmentTransaction fragementTransaction = activity.getSupportFragmentManager().beginTransaction();

            if(fragment1_tag != null)
                fragementTransaction.detach(fragment1);
            if(fragment2 != null)
                fragementTransaction.detach(fragment2);


            fragementTransaction.commit();

        }

    }

The class RealtimeFragment and the corresponding layout fragment_realtime looks like this:

public class RealtimeFragment extends Fragment {

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


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button" />

</LinearLayout>

In one tab now two fragments of the class RealtimeFragment should be displayed. The fragments just show one button but NOTHING is displayed! Why?

Answer 1

I was looking for a solution to the same Topic, and found this, which comes in quite handy.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <fragment android:name="com.example.news.ArticleListFragment"
            android:id="@+id/list"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="match_parent" />
    <fragment android:name="com.example.news.ArticleReaderFragment"
            android:id="@+id/viewer"
            android:layout_weight="2"
            android:layout_width="0dp"
            android:layout_height="match_parent" />
</LinearLayout>

so Reference your Fragments and inflate it, just like a normal Fragment