ActionBar Tabs with multiple fragments

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();
        }
    }
}