Tabs and Fragments, separate back stacks

Question

I am attempting to add Tabs to an existing app to add more functionality I've been able to implement tabs and also move everything to Fragments. However, the way I have it setup at the moment doesn't preserve the stack per tab. So basically I have a main FrameActivity that handles the tabs and attaches the fragments to each tab.

During my research I found this thread: https://stackoverflow.com/a/7480080/792407

The example he gives makes a lot of sense but I can't seem to get the fragments to display. So let me explain what I'm doing to make sure I understand it correctly:

I have a main tab activity which extends FragmentActivity and handles the tabs. Layout looks like:

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">
    <TabHost
        android:id="@android:id/tabhost"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        >
        <LinearLayout
            android:orientation="vertical"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            >
            <TabWidget
                android:id="@android:id/tabs"
                android:orientation="horizontal"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_weight="0"
                />
            <FrameLayout
                android:id="@android:id/tabcontent"
                android:layout_width="0dp"
                android:layout_height="0dp"
                android:layout_weight="0"/>

            <FrameLayout
                android:id="@+android:id/realtabcontent"
                android:layout_width="fill_parent"
                android:layout_height="0dp"
                android:layout_weight="1"/>
        </LinearLayout>
    </TabHost>
</LinearLayout>

Within this activity I initialize my tabs:

mTabHost = getTabHost();        
Resources res = getResources();
Intent intent;        
TabHost.TabSpec spec; 

//search tab
intent = new Intent().setClass(this, searchFragmentStack.class);
spec = mTabHost.newTabSpec("search").setIndicator("Search",res.getDrawable(R.drawable.ic_tab_search)).setContent(intent);        
mTabHost.addTab(spec);

//home tab
intent = new Intent().setClass(this, homeFragmentStack.class);
spec = mTabHost.newTabSpec("home").setIndicator("Home",res.getDrawable(R.drawable.ic_tab_home)).setContent(intent);        
mTabHost.addTab(spec);

The stack classes I'm using look like:

public class searchFragmentStack extends ActivityInTab {
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            navigateTo(new search());
        }
}

The ActivityInTab abstract class is the same code he used in the thread:

abstract class ActivityInTab extends FragmentActivity { // FragmentActivity is just Activity for the support library.

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

    /**
     * Navigates to a new fragment, which is added in the fragment container
     * view.
     * 
     * @param newFragment
     */
    protected void navigateTo(Fragment newFragment) {
        FragmentManager manager = getSupportFragmentManager();
        FragmentTransaction ft = manager.beginTransaction();
        ft.add(R.id.content, newFragment);
        ft.addToBackStack(null);
        ft.commit();
    }

    @Override
    public void onBackPressed() {
        FragmentManager manager = getSupportFragmentManager();
        if (manager.getBackStackEntryCount() > 0) {
            // If there are back-stack entries, leave the FragmentActivity
            // implementation take care of them.
            super.onBackPressed();
        } else {
            // Otherwise, ask user if he wants to leave :)
            //showExitDialog();
        }
    }

}

and the layout for the stack is again based on his example:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/content"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:isScrollContainer="true">
</RelativeLayout>

And that's pretty much it. All I get are black screens in the tabs which makes me think it's a layout issue or I'm just doing it wrong. Does this make sense? Is there a better way? Am I missing something? Any help will be greatly appreciated.

Scott · Answer 1 · 2012-02-16T20:53:10.940

I've figured it out after starting a dummy project and doing everything from scratch:

The activity I was using to handle the tabs needs to be a TabActivity and implimented as if I was creating normal Tabs using Activities, except I'll be using separate FragmentActivity "stacks" to manage the content in each tab. Also, the layout I was using for the Tab activity was wrong for what I was doing, I am now using:

<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/tabhost"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:padding="5dp">
        <TabWidget
            android:id="@android:id/tabs"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" />
        <FrameLayout
            android:id="@android:id/tabcontent"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:padding="5dp" />
    </LinearLayout>
</TabHost>

Those were the two major changes, I've uploaded the source for the test project in case anyone wants to reference it for their own projects:

Seperate Fragment Stacks in Tabs

EDIT

Forgot to mention that TabActivity is deprecated so one shouldn't rely on this method for future android versions. I have not figured out how to implement this using a FragmentActivity. That said, it works for my current needs and gives me time to figure out how to do it the new way.

have you done something with rotations ? Because when you are in tab 1 and fragment B, then rotate you go back to fragment A — Streetboy, Apr 16 '12 at 08:53
@Streetboy you need to save your active fragment name in onSaveInstanceState. So override that method, save the active fragment name and the next time your application starts, look for the string in the savedInstanceState bundle. If you find it, switch to that fragment screen. — Buffalo, Jun 28 '12 at 11:06
I downloaded code from your link, but tabActivity is deprecated api>14 ! Is there any solution fot it. — Ramesh Akula, Jul 03 '12 at 07:30

score 0 · Answer 2 · edited May 23 '17 at 10:26

0

I experimented about tabs in fragment activity. So, may be it is worth to be seen

FragmentTabHost with own fragment stack for each tab

edited May 23 '17 at 10:26

Community

1
1

answered Oct 21 '14 at 02:10

Alexander

35
4

This example is not complete, but demonstrates base functionality of fragment own stack. – Alexander Oct 21 '14 at 02:13

Tabs and Fragments, separate back stacks

2 Answers2