ProjectLaogai/app/src/main/res/drawable/background_splash.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

    <item
            android:drawable="@color/colorPrimary"/>

    <!--TODO when minAPI is 23 use this-->
    <!--<item android:gravity="center" android:width="144dp" android:height="144dp">-->
    <item android:gravity="center">
        <bitmap
                android:gravity="fill_horizontal|fill_vertical"
                android:src="@mipmap/ic_laogai_icon_splash"/>
    </item>

</layer-list>