最近忙，先上示例记录一下。说明：主要都是靠网上各路大神的文章整合后出来的。

build.gradle文件

 defaultConfig {
        applicationId "com.my.mine"
        minSdkVersion 21
        targetSdkVersion 30
        versionCode 101
        versionName "1.0.1"
        javaCompileOptions {
            annotationProcessorOptions.includeCompileClasspath = true
        }
        flavorDimensions "" // https://blog.csdn.net/gengbaolong/article/details/101785549
    }

    // 多包名打包
    productFlavors {
        // 常用 apk
        Main {
            // 设置applicationId（这里很重要，两个相同applicationId的apk不同同时安装在同一台Android手机中）
            applicationId defaultConfig.applicationId
            versionCode defaultConfig.versionCode
            versionName defaultConfig.versionName
            // 自定义定义xxx字段，在AndroidManifest.xml文件中用到${xxx}
            manifestPlaceholders = [
                    app_name : "@string/app_main",
                    app_theme: "@style/mainTheme",
                    app_icon : "@mipmap/app_logo_main"]
        }
        // 另一个 apk
        other1 {
            // 解释同app1
            applicationId "com.my.other1"
            versionCode 101
            versionName "1.0.1_01"
            manifestPlaceholders = [
                    app_name : "@string/app_other1",
                    app_theme: "@style/Other1Theme",
                    app_icon : "@mipmap/app_logo_other1"]
        }
    }

AndroidManifest.xml文件的application，的关键信息。app_theme是适配启动闪屏页

<application
        android:name=".MyApplication"
        android:icon="${app_icon}"
        android:label="${app_name}"
        android:roundIcon="${app_icon}"
        android:theme="${app_theme}">
        ...
 </application>

style.xml文件的theme；其中windowBackground就是启动闪屏页

    <!-- Main application theme. -->
    <style name="MainTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="windowActionBar">false</item>
        <item name="android:windowBackground">@drawable/splash_background</item>
        <item name="colorPrimary">@color/white</item>
        <item name="colorPrimaryDark">@color/white</item>
        <item name="colorAccent">@color/white</item>
        <item name="android:windowDrawsSystemBarBackgrounds">true</item>
    </style>

    <!--Other1的主题样式-->
    <style name="HenglinAppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="windowActionBar">false</item>
        <item name="android:windowBackground">@drawable/splash_background_other</item>
        <item name="colorPrimary">@color/white</item>
        <item name="colorPrimaryDark">@color/white</item>
        <item name="colorAccent">@color/white</item>
        <item name="android:windowDrawsSystemBarBackgrounds">true</item>
    </style>

splash_background_other.xml

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

    <!--  闪屏页背景 ，好处适配各种屏幕 -->
    <item android:drawable="@color/white"/>

    <!-- app logo -->
    <item>
        <bitmap
            android:gravity="center"
            android:src="@drawable/icon_logo"/>
    </item>
</layer-list>