How to resume child fragments on parent fragment resume

Question

I have a fragment called the MainFragment with a TabLayout . The TabLayout has two tabs with a fragment each. Lets call it Fragment A and Fragment B .

When I open the MainFragment , Fragment A and Fragment B are populated within the TabLayout as expected. When I resume MainFragment , Fragment A and Fragment B are not resumed, and I get two empty tabs.

My MainFragment looks like this

    @Override
    public View onCreateView(
            LayoutInflater inflater, @Nullable ViewGroup container,
            @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.main_fragment, null);
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        Injector.component().inject(this);

        setupViewPager(viewPager);
        tabLayout.setupWithViewPager(viewPager);

    }

    private void setupViewPager(ViewPager viewPager) {
        ViewPagerAdapter adapter = new ViewPagerAdapter(getFragmentManager());
        adapter.addFragment(new FragmentA(), "Fragment A");
        adapter.addFragment(new FragmentB(), "Fragment B");
        viewPager.setAdapter(adapter);
    }

How do I solve this?

Answer 1

由于Fragments A和B是MainFragment子片段， MainFragment使用getChildFragmentManager()而不是getFragmentManager()