我创建了一个闪屏使用这篇文章从MS：
https://learn.microsoft.com/en-us/xamarin/android/user-interface/splash-screen
问题是，当应用程序启动时：
1.它以红色背景开始
1.然后加载闪屏图像
1.然后加载MainActivity

我如何摆脱第一步？我想直接显示闪屏。

在MainActivity中，我设置了MainLauncher = false和Theme =“@style/MainTheme”：

[Activity(Label = "S", Icon = "@mipmap/icon", Theme = "@style/MainTheme", MainLauncher = false, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]

splash_screen.xml：

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" android:opacity="opaque">
  <item>
    <color android:color="@color/splash_background"/>
  </item>
  <item>
    <bitmap
        android:src="@drawable/splash_logo"
        android:tileMode="disabled" 
        /><!--deleted android:gravity="center" to get a fullscreen image-->
  </item>
</layer-list>

style.xml:

<?xml version="1.0" encoding="utf-8" ?>
<resources>
  <!-- Base theme applied no matter what API -->
  <style name="MainTheme.Base" parent="Theme.AppCompat.Light.DarkActionBar">
    <!--If you are using revision 22.1 please use just windowNoTitle. Without android:-->
    <item name="windowNoTitle">true</item>
    <!--We will be using the toolbar so no need to show ActionBar-->
    <item name="windowActionBar">false</item>
    <!-- Set theme colors from http://www.google.com/design/spec/style/color.html#color-color-palette -->
    <!-- colorPrimary is used for the default action bar background -->
    <item name="colorPrimary">#2196F3</item>
    <!-- colorPrimaryDark is used for the status bar -->
    <item name="colorPrimaryDark">#1976D2</item>
    <!-- colorAccent is used as the default value for colorControlActivated
         which is used to tint widgets -->
    <item name="colorAccent">#FF4081</item>
    <!-- You can also set colorControlNormal, colorControlActivated
         colorControlHighlight and colorSwitchThumbNormal. -->
    <item name="windowActionModeOverlay">true</item>

    <item name="android:datePickerDialogTheme">@style/AppCompatDialogStyle</item>
  </style>

  <style name="MainTheme.Splash" parent ="Theme.AppCompat.Light.NoActionBar">
    <item name="android:windowBackground">@drawable/splash_screen</item>
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowFullscreen">true</item>
    <item name="android:windowContentOverlay">@null</item>
    <item name="android:windowActionBar">true</item>
  </style>
  <style name="MainTheme" parent="MainTheme.Base">
  </style>
  <style name="AppCompatDialogStyle" parent="Theme.AppCompat.Light.Dialog">
    <item name="colorAccent">#FF4081</item>
  </style>
</resources>

SplashActivity.cs:

[Activity(Theme = "@style/MainTheme.Splash", MainLauncher = true, NoHistory = true, ScreenOrientation = ScreenOrientation.Portrait) ]
    public class SplashActivity : AppCompatActivity
    {
        static readonly string TAG = "X:" + typeof(SplashActivity).Name;

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

        // Launches the startup task
        protected override void OnResume()
        {
            base.OnResume();

            Task startupWork = new Task(() => { SimulateStartup(); });
            startupWork.Start();
            SimulateStartup();
        }

        // Simulates background work that happens behind the splash screen
       async void SimulateStartup()
        {
            //Log.Debug(TAG, "Performing some startup work that takes a bit of time.");
            await Task.Delay(5000); // Simulate a bit of startup work.

            //Log.Debug(TAG, "Startup work is finished - starting MainActivity.");
            StartActivity(new Intent(Application.Context, typeof(MainActivity)));
        }

        public override void OnBackPressed() { }
    }
}