ViewPager inside Fragment loses content when returning to it

Question

I am implementing tabhost using FragmentActivity , under the first tab i load a welcome fragment that contains a Viewpager and CirclePageIndIcator, I need to load 4 views in side that WelcomeFragment

this is my WelcomeFragment

public class WelcomeFragment extends Fragment
{
     PageAdapter mAdapter;
        ViewPager mPager;
        CirclePageIndicator mIndicator;
        List<Fragment> fragments;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.frag_welcome_layout,null);
        mPager=(ViewPager)view.findViewById(R.id.myViewPager);
        mIndicator=(CirclePageIndicator)view.findViewById(R.id.circlePageIndicator1);
        fragments=new ArrayList<Fragment>();
        return view;
    }
    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        Fragment fragment;
        for(int i=0;i<4;i++)
        {
            fragment= Fragment.instantiate(getActivity(), TipsFragment.class.getName());
            fragments.add(fragment);
        }
            mAdapter = new PageAdapter(getFragmentManager(),fragments);
            mPager.setAdapter(mAdapter);
        mIndicator.setViewPager(mPager);
    }
}

and this is my page adapter

public class PageAdapter extends FragmentPagerAdapter implements Serializable{

    List<Fragment> fragments;
    public PageAdapter(FragmentManager fm,List<Fragment> frags) {
        super(fm);
        fragments = frags;

    }

    @Override
    public Fragment getItem(int arg0) {
        // TODO Auto-generated method stub
        return TipsFragment.newInstance(0, 0);
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return 4;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        FragmentManager manager = ((Fragment) object).getFragmentManager();
        FragmentTransaction trans = manager.beginTransaction();
        trans.remove((Fragment) object);
        trans.commit();

        super.destroyItem(container, position, object);
    }

}

When I load the app first the tabFragmentActivity load successfully and the viewpager inside the welcomeFragment works fine, but when I move to 2nd tab and comes back to the 1st tab again the ViewPager doesn't load successfully.

How can i solve it?

as per the suggestion i used getChildFragmentManager but app got crash error in logcat

09-09 13:28:39.412: E/AndroidRuntime(3100): FATAL EXCEPTION: main
09-09 13:28:39.412: E/AndroidRuntime(3100): java.lang.IllegalStateException: No activity
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1091)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1086)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1877)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.support.v4.app.Fragment.performActivityCreated(Fragment.java:1492)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:947)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1460)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.os.Handler.handleCallback(Handler.java:725)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.os.Handler.dispatchMessage(Handler.java:92)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.os.Looper.loop(Looper.java:137)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at android.app.ActivityThread.main(ActivityThread.java:5041)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at java.lang.reflect.Method.invokeNative(Native Method)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at java.lang.reflect.Method.invoke(Method.java:511)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
09-09 13:28:39.412: E/AndroidRuntime(3100):     at dalvik.system.NativeStart.main(Native Method

)

Nidia

Answer 1

if you are using your ViewPager in a Fragment, when you are creating a new adapter, you should use ChildFragmentManager:

getChildFragmentManager()

Sneaking

Answer 2

Try this:

    ViewPager pager = [your viewPAger]
    pager.setOffscreenPageLimit([quantity of tabs that you are going to use]);

with that sentence (pager.setOffscreenPageLimit) you can specify how far away a tab can stand before it get erased by the ViewPager!

Cheers!

Touchback

Answer 3

Use an AsyncTask to set the ViewPagerAdapter:

private class SetAdapterTask extends AsyncTask<Void, Void, Void> {
        protected Void doInBackground(Void... params) {
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {

            if(mPagerAdapter != null) mViewPager.setAdapter(mPagerAdapter);
        }
    }   

Call it like this:

mAdapter = new PageAdapter(getChildFragmentManager(), fragments);
new SetAdapterTask().execute();

instead of calling:

mViewPager.setAdapter(mPagerAdapter);

And set the Adapter inside the onCreateView(...) method, not onActivityCreated(...).

Also, use getChildFragmentManager() instead of getFragmentManager().

Prance

Set the adapter in the onCreateView() method. You are doing it in onActivityCreated(), which is only called once. – Prance

Also, you need to use getChildFragmentManager(). I updated my answer. – Prance

as your suggestion i use childFragmentManager() now when i come back from 2nd tab to 1st tab... the application crashd.... and error log also given above – Nidia

I dont see your error message. Could you pastebin the current code of your fragment and the error log. pastebin.com – Prance

@user1672337 did you solve this problem? i am having the same problem – Undercharge

ya...it correct for nested fragment, need to use new instance and getChildFragmentManager – Aliaalias

@PhilippJahoda.. Its not working. If I click the tab 1st time its loading fine but if I switch back to other tab & come back then app is getting crashed with IllegalStateException : No Activity – Pyroelectricity