AndroidManifest.xml
设置 android:theme=“@style/LaunchTheme”

<application
        android:label="@string/app_name"
        android:name="${applicationName}"
        android:icon="@mipmap/ic_launcher"
        android:roundIcon="@mipmap/ic_launcher"
        android:theme="@style/LaunchTheme">
        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:launchMode="singleTop"
            android:taskAffinity=""
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize">
            <!-- Specifies an Android theme to apply to this Activity as soon as
                 the Android process has started. This theme is visible to the user
                 while the Flutter UI initializes. After that, this theme continues
                 to determine the Window background behind the Flutter UI. -->
            <meta-data
              android:name="io.flutter.embedding.android.NormalTheme"
              android:resource="@style/NormalTheme"
              />
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
        <!-- Don't delete the meta-data below.
             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
        <meta-data
            android:name="flutterEmbedding"
            android:value="2" />
    </application>

styles.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="LaunchTheme" parent="@android:style/Theme.Light.NoTitleBar">
        <item name="android:windowBackground">@drawable/launch_background</item>
    </style>
    <style name="NormalTheme" parent="@android:style/Theme.Light.NoTitleBar">
        <item name="android:windowBackground">?android:colorBackground</item>
    </style>
</resources>

launch_background.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <bitmap android:src="@drawable/launch_image" />
    </item>
    <item
        android:width="65dp"
        android:height="326dp"
        android:gravity="center_horizontal|clip_vertical"
        android:top="145dp">
        <bitmap android:src="@drawable/ver6_bg_word" />
    </item>
    <item
        android:width="209dp"
        android:height="66dp"
        android:bottom="18dp"
        android:gravity="bottom|center_horizontal">
        <bitmap android:src="@drawable/ver6_prod_logo" />
    </item>
</layer-list

项目结构：

iOS LaunchScreen.storyboard 的使用和适配

修复项目中的警告⚠️
dart fix --apply --code=unused_import
dart fix --apply --code=use_key_in_widget_constructors