Android APP 启动白屏优化

<resources>
    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <!--parent设置为启动页的theme-->
    <style name="AppTheme.customeTheme" parent="AppTheme">
        <item name="android:windowBackground">@drawable/bg</item>
    </style>
</resources>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.example.xiao.custom_launch">

    <application
  			...此处省略很多代码...
        android:theme="@style/AppTheme">

        <!--启动activity的theme设为自定义的customeTheme-->
        <activity android:name=".MainActivity"
            android:theme="@style/AppTheme.customeTheme">
        		...此处省略很多代码...
        </activity>
    </application>
</manifest>