ViewPager and fragments — what's the right way to store fragment's state?

Question

Fragments seem to be very nice for separation of UI logic into some modules. But along with ViewPager its lifecycle is still misty to me. So Guru thoughts are b

Answer 1

My solution is very rude but works: being my fragments dynamically created from retained data, I simply remove all fragment from the PageAdapter before calling super.onSaveInstanceState() and then recreate them on activity creation:

@Override
protected void onSaveInstanceState(Bundle outState) {
    outState.putInt("viewpagerpos", mViewPager.getCurrentItem() );
    mSectionsPagerAdapter.removeAllfragments();
    super.onSaveInstanceState(outState);
}

You can't remove them in onDestroy(), otherwise you get this exception:

java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState

Here the code in the page adapter:

public void removeAllfragments()
{
    if ( mFragmentList != null ) {
        for ( Fragment fragment : mFragmentList ) {
            mFm.beginTransaction().remove(fragment).commit();
        }
        mFragmentList.clear();
        notifyDataSetChanged();
    }
}

I only save the current page and restore it in onCreate(), after the fragments have been created.

if (savedInstanceState != null)
    mViewPager.setCurrentItem( savedInstanceState.getInt("viewpagerpos", 0 ) );