Xamarin.Android项目：片段中的ViewPager显示空白

Question

在我的项目中，我有一些片段布局。

在Main.axml中，我使用CoordinatorLayout和NavigationView导航到我的布局。这没问题。但在一个片段中，我想使用TabLayout和ViewPager来显示两个子布局，这也是片段，我有问题。当我切换TabLayout时，ViewPager显示为空白。

简而言之，Fragment和ViewPager中的ViewPager中没有任何内容。

我调试了两天，并搜索了很多方法来解决这个问题，但没用。这是我的部分代码。

提前致谢

Interface Image

片段布局有ViewPager

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <android.support.design.widget.TabLayout
        android:id="@+id/astroTabLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <android.support.v4.view.ViewPager
        android:id="@+id/astroViewPager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

其片段代码

class AstroFragment : Fragment
        {
            ViewPager astroViewPager;
            TabLayout astroTabLayout;

            public override void OnStart()
            {
                base.OnStart();
            }

            public override void OnCreate(Bundle savedInstanceState)
            {
                base.OnCreate(savedInstanceState);
            }

            public override void OnViewCreated(View view, Bundle savedInstanceState)
            {
                base.OnViewCreated(view, savedInstanceState);           
            }

            public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
            {
                View view = inflater.Inflate(Resource.Layout.AstroFragment, container, false);

                astroViewPager = view.FindViewById<ViewPager>(Resource.Id.astroViewPager);
                astroTabLayout = view.FindViewById<TabLayout>(Resource.Id.astroTabLayout);

                MyFragmentPagerAdapter adapter = new MyFragmentPagerAdapter(ChildFragmentManager);
                astroViewPager.Adapter = adapter;
                astroViewPager.SetCurrentItem(0, true);
                astroViewPager.OffscreenPageLimit = 2;

                astroTabLayout.SetupWithViewPager(astroViewPager);

                return view;
            }
        }

一个子片段布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
              android:padding="30px">
    <TextView
        android:text="data"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

一个子片段代码

class AstroDataFragment : Android.Support.V4.App.Fragment
    {
        public override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            // Create your fragment here
        }

        public override void OnViewCreated(View view, Bundle savedInstanceState)
        {
            base.OnViewCreated(view, savedInstanceState);
        }

        public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
            // Use this to return your custom view for this Fragment
            View view = inflater.Inflate(Resource.Layout.AstroDataFragment, container, false);

            return view;
        }
    }

MyFragmentPagerAdapter代码

class MyFragmentPagerAdapter : FragmentPagerAdapter
    {
        const int PAGE_COUNT = 2;
        private string[] tabTitles = { "视图一", "网页图表" };
        private List<Android.Support.V4.App.Fragment> fragments = new List<Android.Support.V4.App.Fragment>();

        public MyFragmentPagerAdapter(Android.Support.V4.App.FragmentManager fm) : base(fm)
        {
            // Sub Fragments
            fragments.Add(new AstroDataFragment());
            fragments.Add(new AstroImageFragment());                
        }

        public override int Count
        {
            get
            {
                return PAGE_COUNT;
            }
        }

        public override void DestroyItem(ViewGroup container, int position, Java.Lang.Object @object)
        {
            //base.DestroyItem(container, position, @object);
        }

        public override Android.Support.V4.App.Fragment GetItem(int position)
        {
            return fragments[position];
        }

        public override ICharSequence GetPageTitleFormatted(int position)
        {
            var charSequence = CharSequence.ArrayFromStringArray(tabTitles);

            return charSequence[position];
        }
    }