在android手机上打开flutter应用的时候，首先会进入到原生的Activity，我们在AndroidManifest.xml中的activity会添加theme，theme会设置背景
<activity
android:name=".MainActivity"
android:launchMode="singleTop"
android:theme="@style/LaunchTheme" //这个主体有一个背景
android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
android:hardwareAccelerated="true"
android:windowSoftInputMode="adjustResize">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
1、我们的styles.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="LaunchTheme" parent="@android:style/Theme.Black.NoTitleBar">
<!-- Show a splash screen on the activity. Automatically removed when
Flutter draws its first frame -->
<item name="android:windowBackground">@drawable/launch_background</item>
<item name="android:statusBarColor">#ffffff</item>
<item name="android:windowTranslucentStatus">true</item>
<item name="android:windowIsTranslucent">false</item>
<item name="android:windowNoTitle">true</item>
</style>
2、在打开Flutter对应的AndroidManifest.xml中的activity标签内添加如下两条
<meta-data
android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
android:value="true" />
<meta-data
android:name="io.flutter.embedding.android.SplashScreenDrawable"
android:resource="@drawable/launch_background" />
