在片段内显示片段时获取空白页？

Question

这是我在导航菜单中的片段。

class MirandaFragment extends Fragment {
    protected View view;
    FragmentPagerAdapter adapterViewPager;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        view = inflater.inflate(R.layout.miranda, container, false);
        ViewPager vpPager = (ViewPager) view.findViewById(R.id.vpPager);
        adapterViewPager = new MyPageAdapter(getFragmentManager());
        vpPager.setAdapter(adapterViewPager);


        return view;
    }
}

这是我设置两个片段EngMiranda和SpaMiranda的适配器。

class MyPageAdapter extends FragmentPagerAdapter {
private static int NUM_ITEMS = 2;

public MyPageAdapter(FragmentManager fragmentManager) {
    super(fragmentManager);
}

// Returns total number of pages.
@Override
public int getCount() {
    return NUM_ITEMS;
}

// Returns the fragment to display for a particular page.
@Override
public Fragment getItem(int position) {
    switch (position) {
        case 0:
            return EngMiranda.newInstance("Fragment 1", getCount());
        case 1:
            return SpaMiranda.newInstance("Fragment 2", getCount());
        default:
            return null;
    }
}

// Returns the page title for the top indicator
@Override
public CharSequence getPageTitle(int position) {
    switch (position) {
        case 0:
            return "English";
        case 1:
            return "Spanish";
        default:
            return null;
    }

}

}

应用程序第一次打开后，我可以打开片段并查看其中的选项卡片段，但是当我们第二次打开该片段时，适配器不会显示。