Replace Fragment over Fragment that contains ViewPager

Question

I have ONE activity that calls a FragmentParent. This contains a viewpager. The viewpager has 2 tabs. In each tab there is a fragment. In the first tab (TAB-A) there is a fragment that contains a Recyclerview. When I click over an item the app opens new fragment, but when I go back ALL the fragments inside the viewpager get empty.

I am using Fragments and support library v-13, I already tried with v-4 but I had the same issue.

This is my code:

activity_main.xml

MainActivity.java

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

    initWithFragments(savedInstanceState);
}

public void initWithFragments(Bundle savedInstanceState) {

    if (findViewById(R.id.fragment_container) != null) {

        if (savedInstanceState != null) {
            return;
        }
        // Create a new Fragment to be placed in the activity layout
        MainFragment mainFragment = new MainFragment();
        //Fragment transaction
        FragmentTransaction ft = getFragmentManager().beginTransaction();
        ft.add(R.id.fragment_container, mainFragment);
        ft.commit();
    }
}

MainFragment

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

    //Enabled menu
    setHasOptionsMenu(true);

    // Initialize Toolbar and View Pager
    toolbar = (Toolbar) rootView.findViewById(R.id.toolbar);
    ((AppCompatActivity) getActivity()).setSupportActionBar(toolbar);

    // Create the adapter that will return a fragment for each section
    SectionsPageAdapter mSectionsPagerAdapter = new SectionsPageAdapter(getFragmentManager());

    // Set up the ViewPager with the sections adapter.
    ViewPager mViewPager = (ViewPager) rootView.findViewById(R.id.container_view_pager);
    mViewPager.setAdapter(mSectionsPagerAdapter);
    mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            switch (position) {
                case 0:
                    toolbar.setTitle("Home");
                    break;
                case 1:
                    toolbar.setTitle("Downloads");
                    break;
                default:
                    break;
            }
        }

        @Override
        public void onPageSelected(int position) {
        }

        @Override
        public void onPageScrollStateChanged(int state) {
        }
    });

    // Set up tab layout
    TabLayout tabLayout = (TabLayout) rootView.findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(mViewPager);

    return rootView;
}

fragment_app

This is the FragmentA inside the viewpager

Also I have the PageAdapter

public class SectionsPageAdapter extends FragmentPagerAdapter {

private int NUM_PAGES = 2;

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

@Override
public Fragment getItem(int position) {
    // getItem is called to instantiate the fragment for the given page.
    // Return a PlaceholderFragment (defined as a static inner class below).
    switch (position) {
        case 0:
            return SearchFragment.newInstance();
        case 1:
            return DownloadFragment.newInstance();
        default:
            return new Fragment();
    }
}

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

@Override
public CharSequence getPageTitle(int position) {
    switch (position) {
        case 0:
            return "Search";
        case 1:
            return "Downloads";
    }
    return null;
}

}

I am using FragmentTransaction to replace Fragments...

FragmentTransaction ft = getFragmentManager().beginTransaction();
    ft.replace(R.id.fragment_container,settingFragment);
    ft.addToBackStack(null);
    ft.commit();

If you guys can help me, I will really appreciate Thanks

This is what I want to:

Josymar De Leon · Accepted Answer

I finally resolved using getChildFragments:

I used getChildFragmentManager instead of getFragmentManager. I passed to the constructor of the PageAdapter

SectionsPageAdapter mSectionsPagerAdapter = new SectionsPageAdapter(getChildFragmentManager());

In the view holder of the RecyclerView I created an Interface to communicate Nested Fragments with the Activity(main container). Using this way I could replace Fragments in the R.id.fragment_container

I found the solution in this link: Adding child Fragment to Parent Fragment withing a ViewPager in Android

Replace Fragment over Fragment that contains ViewPager

Answers (2)

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