Android Splash Screen Launcher Theme (based on https://android.jlelse.eu/the-complete-android-splash-screen-guide-c7db82bce565 )

AndroidManifest.xml

<?xml version="1.0" encoding="UTF-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android">
    <application>
      
      <!-- Set AppTheme.Launcher for launcher activity -->
        <activity
            android:name=".MainActivity"
            android:theme=”@style/AppTheme.Launcher”>
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
      <!-- ... -->
  </application>

  <!-- ... -->

</manifest>

launch_screen.xml

<?xml version="1.0" encoding="utf-8"?>

<!-- The android:opacity=”opaque” line — this is critical in preventing a flash of black as your theme transitions. -->
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" android:opacity="opaque">
  
  <!-- The background color, preferably the same as your normal theme -->
  <item android:drawable="@android:color/white"/>
  
  <!-- Your product logo - 144dp color version of your app icon -->
  <item>
    
    <bitmap
      android:src="@drawable/product_logo_144dp"
      android:gravity="center"/>
    
  </item>
  
</layer-list>

MainActivity.kt

class MainActivity: AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) { 
        // Make sure this is before calling super.onCreate 
        setTheme(R.style.AppTheme)
        super.onCreate(savedInstanceState)
        // …
    }

}

styles.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
  
  <!-- Your AppTheme or other themes/styles here -->
  
  <!-- The launcher theme. It sets the main window background to the launch_screen drawable -->
  <style name=”AppTheme.Launcher”>
    <item name=”android:windowBackground”>@drawable/launch_screen</item>
    <!-- Optional, on Android 5+ you can modify the colorPrimaryDark color to match the windowBackground color for further branding-->
    <!-- <item name="colorPrimaryDark">@android:color/white</item> -->
  </style>
  
</resources>