Set Launcher Screen Backgrounds：

<style name="launcher" parent="Theme.AppCompat.NoActionBar">
    <item name="android:windowFullscreen">true</item>
    <item name="android:windowBackground">@drawable/launcher</item>
</style>

<style name="dialog" parent="Theme.AppCompat.Dialog.Alert">
    <item name="android:windowBackground">#00000000</item>
</style>

Then goto AndroidManifest.xml set this style to launcher activity