Question

I’ve been trying to update my app and get going with fragments, the
action bar, and all the other UI features that I’m missing out on. I
understand I can have multiple fragments in an activity, have
different layouts based upon the device and all that good stuff but
I’m struggling with getting some tab stuff the way I want. I
understand how to add tabs, switching between them but how do I have
more than one fragment in a tab? So for example I have essentially two
screens I want the user to be able to switch back and forth from
easily (why I want to use tabs). If I have two separate activities I
can specify this in xml files and use setContentView using the layouts
below

tab1_layout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <fragment
        android:name="com.example.tabrefactor.Fragment1"
        android:id="@+id/fragment_1"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"/>
    <fragment
        android:name="com.example.tabrefactor.Fragment2"
        android:id="@+id/fragment_2"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"/>
    <fragment
        android:name="com.example.tabrefactor.Fragment3"
        android:id="@+id/fragment_3"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"/>
</LinearLayout>

tab2_layout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <fragment
        android:name="com.example.tabrefactor.Fragment4"
        android:id="@+id/fragment_4"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"/>
</LinearLayout>

I can convert the second layout to using tabs since its only contains
one fragment but I’m not sure how get the first layout into a single
tab. Is that something that’s allowed? Thanks in advance,

Jason Prenger

Answer 1

I’ll leave this open incase someone has a simplification or a better idea…

Eventually went with a workaround of having a base layout with 3 frame layouts…

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

    <FrameLayout
        android:id="@+id/fragment_sb"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>
    <FrameLayout
        android:id="@+id/fragment_local"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>
    <FrameLayout
        android:id="@+id/fragment_rest"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="1"/>

</LinearLayout>

Then in my activity with the tabs I made a custom TabListener that handled the changes between. The code I used is below (I’m using actionbarsherlock so it’ll look slightly different than the normal stuff)

public class TabActivity extends FragmentActivity {

    Fragment1 fragment1;
    Fragment2 fragment2;
    Fragment3 fragment3;
    Fragment4 fragment4;

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

        final ActionBar bar = getSupportActionBar();
        bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        bar.setDisplayShowTitleEnabled(true);
        bar.setDisplayShowHomeEnabled(false);
        bar.setTitle("Title");

        bar.addTab(bar.newTab()
                .setIcon(R.drawable.ic_list_tab_selected)
                .setTabListener(new ListTabListener(this)));
        bar.addTab(bar.newTab()
                .setIcon(R.drawable.ic_map_tab_selected)
                .setTabListener(new MapTabListener(this)));

        if (savedInstanceState != null) {
            bar.setSelectedNavigationItem(savedInstanceState.getInt("tab", 0));
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("tab", getSupportActionBar().getSelectedNavigationIndex());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.test_menu, menu);

        return super.onCreateOptionsMenu(menu);
    }

    public static class ListTabListener implements ActionBar.TabListener {
        private static final String fragment1Tag = "fragment1_tag";
        private static final String fragment2Tag = "fragment2_tag";
        private static final String fragment3Tag = "fragment3_tag";

        private FragmentActivity activity;
        private Fragment1 fragment1;
        private Fragment2 fragment2;
        private Fragment3 fragment3;

        public ListTabListener(FragmentActivity activity) {
            this.activity = activity;

            FragmentTransaction ft = activity.getSupportFragmentManager().beginTransaction();
            fragment1 = (Fragment1) activity.getSupportFragmentManager().findFragmentByTag(fragment1Tag);
            if (fragment1 != null && !fragment1.isDetached()) {
                ft.detach(fragment1);
            }

            fragment2 = (Fragment2) activity.getSupportFragmentManager().findFragmentByTag(fragment1Tag);
            if (fragment2 != null && !fragment2.isDetached()) {
                ft.detach(fragment2);
            }

            fragment3 = (Fragment3) activity.getSupportFragmentManager().findFragmentByTag(fragment1Tag);
            if (fragment3 != null && !fragment3.isDetached()) {
                ft.detach(fragment3);
            }

            ft.commit();
        }

        @Override
        public void onTabReselected(Tab tab, FragmentTransaction nullFt) {
            //Reselected don't do anything          
        }

        @Override
        public void onTabSelected(Tab tab, FragmentTransaction nullFt) {
            FragmentTransaction ft = activity.getSupportFragmentManager().beginTransaction();

            if(fragment1 == null) {
                fragment1 = new Fragment1();
                ft.add(R.id.fragment_sb, fragment1, fragment1Tag);
            } else {
                ft.attach(fragment1);
            }

            if(fragment2 == null) {
                fragment2 = new Fragment2();
                ft.add(R.id.fragment_local, fragment2, fragment2Tag);
            } else {
                ft.attach(fragment2);
            }

            if(fragment3 == null) {
                fragment3 = new Fragment3();
                ft.add(R.id.fragment_rest, fragment3, fragment3Tag);
            } else {
                ft.attach(fragment3);
            }

            ft.commit();
        }

        @Override
        public void onTabUnselected(Tab tab, FragmentTransaction nullFt) {
            FragmentTransaction ft = activity.getSupportFragmentManager().beginTransaction();

            if(fragment1 != null)
                ft.detach(fragment1);
            if(fragment2 != null)
                ft.detach(fragment2);
            if(fragment3 != null)
                ft.detach(fragment3);

            ft.commit();
        }
    }

    public static class MapTabListener implements ActionBar.TabListener {
        private static final String fragment4Tag = "fragment4_tag";

        private FragmentActivity activity;
        private Fragment4 fragment4;

        public MapTabListener(FragmentActivity activity) {
            this.activity = activity;

            FragmentTransaction ft = activity.getSupportFragmentManager().beginTransaction();
            fragment4 = (Fragment4) activity.getSupportFragmentManager().findFragmentByTag(fragment4Tag);
            if (fragment4 != null && !fragment4.isDetached()) {
                ft.detach(fragment4);
            }
            ft.commit();
        }

        @Override
        public void onTabReselected(Tab tab, FragmentTransaction nullFt) {
            //Reselected don't do anything          
        }

        @Override
        public void onTabSelected(Tab tab, FragmentTransaction nullFt) {
            FragmentTransaction ft = activity.getSupportFragmentManager().beginTransaction();

            if(fragment4 == null) {
                fragment4 = new Fragment4();
                ft.add(R.id.fragment_rest, fragment4, fragment4Tag);
            } else {
                ft.attach(fragment4);
            }

            ft.commit();
        }

        @Override
        public void onTabUnselected(Tab tab, FragmentTransaction nullFt) {
            FragmentTransaction ft = activity.getSupportFragmentManager().beginTransaction();

            if(fragment4 != null)
                ft.detach(fragment4);

            ft.commit();
        }
    }
}