我尝试使用admob向我的应用程序添加广告，但运行应用程序后出现此错误：“Java.Lang.IllegalArgumentException：'未找到片段ShellItemRenderer{...}的ID 0x 1（未知）的视图...
MainActivity.cs中的OnCreate：

protected override void OnCreate(Bundle savedInstanceState)
        {
            FFImageLoading.Forms.Platform.CachedImageRenderer.Init(true);
            base.OnCreate(savedInstanceState);

            Xamarin.Essentials.Platform.Init(this, savedInstanceState);
            global::Xamarin.Forms.Forms.Init(this, savedInstanceState);

            MobileAds.Initialize(ApplicationContext);
            string adUnitId = Resources.GetString(Resource.String.banner_ad_unit_id);
            SetContentView(Resource.Layout.activity_main);
            AdView adView = FindViewById<AdView>(Resource.Id.adView);
            var adRequest = new AdRequest.Builder().Build();
            adView.LoadAd(adRequest);

            LoadApplication(new App());
        }

activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:ads="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.google.android.gms.ads.AdView
        android:id="@+id/adView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        ads:adSize="BANNER"
        ads:adUnitId="ca-app-pub-***" />
</RelativeLayout>

有什么问题？
你能帮我解决这个问题吗？