当我回来时,Android片段在viewpager中为空

Question

我有一个导航抽屉,其中有一个扩展片段的ViewPager.当我点击抽屉的项目时,我打开其中有三个片段的viewpager.它完美地运作.但如果我再次点击相同的抽屉项目再次打开viewpager,则viewpager为空..我可以看到标签但不是那里的片段.这是Viewpager:

public class ViewPagerManager extends Fragment {
    public static ViewPagerManager instance = null;
    Toolbar toolbar;
    public static PagerSlidingTabStrip tabs;
    public MyPagerAdapter adapter;
    public ViewPager pager;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.activity_tabbed, container, false);
        instance = this;
        adapter = new MyPagerAdapter(getFragmentManager());

        pager = (ViewPager)view.findViewById(R.id.pager);
        tabs = (PagerSlidingTabStrip)view.findViewById(R.id.tabs);

        pager.setAdapter(adapter);
        tabs.setViewPager(pager);

        pager.setOffscreenPageLimit(3);

        adapter.notifyDataSetChanged();
        pager.invalidate();
        return view;
    }

    public class MyPagerAdapter extends FragmentPagerAdapter {

        private final String[] TITLES = { "One", "Two", "Three" };

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

        @Override
        public CharSequence getPageTitle(int position) {
            return TITLES[position];
        }

        @Override
        public int getCount() {
            return TITLES.length;
        }
        @Override
        public int getItemPosition(Object object) {
            return POSITION_NONE;

        }


        @Override
        public Fragment getItem(int position) {
            switch (position) {
            case 0:
                // Top Rated fragment activity
                return new FragmentOne();
            case 1:
                // Games fragment activity
                return new FragmentTwo();
            case 2:
                // Games fragment activity
                return new FragmentThree();

            }

            return null;
        }
    }
}

这是正常的吗？我怎么解决？如果可以帮助我使用PagerSlidingTabStrip库.

Answer 1

使用此代码

 adapter = new MyPagerAdapter(getChildFragmentManager()); 

代替

adapter = new MyPagerAdapter(getFragmentManager());