How do I let views keep their states in a Fragment?

Question

Views (in this case, ViewPagers) have their own implementation of saving and restoring state, and I was relying on it to keep my ViewPager on the same page after a device rotate.

It worked perfectly fine when the ViewPager was in an Activity. I'd scroll to a page, rotate the device, and it'd still be on that page. No code was needed in onSaveInstanceState.

I've since converted that Activity into a fragment. Now, the ViewPager doesn't keep its state! If I scroll to a page and rotate the device, it goes back to page 1.

I know that I can save and restore the page in onSaveInstanceState and onCreateView, but I'd rather let the view do it on its own, especially as I add more views and it becomes more complex.

How do I get back this view restoring functionality with fragments?

Here's my fragment:

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class Dashboard extends Fragment {

    private PagerAdapter pagerAdapter;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        pagerAdapter = new PagerAdapter(getChildFragmentManager());
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.dashboard, container, false);

        // irrelevant bits removed

        ViewPager pager = (ViewPager) view.findViewById(R.id.dashboard_pager);
        pager.setOffscreenPageLimit(3);
        pager.setAdapter(pagerAdapter);

        PagerSlidingTabStrip tabs = (PagerSlidingTabStrip) view.findViewById(R.id.dashboard_tabs);
        tabs.setShouldExpand(true);
        tabs.setViewPager(pager);

        return view;
    }

    class PagerAdapter extends FragmentStatePagerAdapter implements PagerSlidingTabStrip.CustomTabProvider {

        public PagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            switch (position) {
                case 0:
                    return Fragment.instantiate(getActivity(), Fragment1.class.getName());
                case 1:
                    return Fragment.instantiate(getActivity(), Fragment2.class.getName());
                case 2:
                    return Fragment.instantiate(getActivity(), Fragment3.class.getName());
            }

            return null;
        }

        @Override
        public int getCount() {
            return 3;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            switch (position) {
                case 0:
                    return "*removed*";
                case 1:
                    return "*removed*";
                case 2:
                    return "*removed*";
            }

            return null;
        }

        @Override
        public View getCustomTabView(ViewGroup viewGroup, int i) {
            return getActivity().getLayoutInflater().inflate(R.layout.tab, viewGroup, false);
        }
    }
}

Answer 1

Have you checked this answer?

If you find if your fragment is still alive in onSavedInstanceState(), you can avoid it.

Apart from that I assume you are aware of android:configChanges= "orientation|screenSize"