安卓本地 Scheduled Notification

原始的AndroidManifest.xml，无法在APP被杀死后接受scheduled消息

<manifest xmlns:android="http://schemas.android.com/apk/res/android">
    <uses-permission android:name = "android.pr"/>
   <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
   <uses-permission android:name="android.permission.VIBRATE" />
   <uses-permission android:name="android.permission.USE_FULL_SCREEN_INTENT" />
   <!-- NOTE: the example app requests USE_EXACT_ALARM to make it easier to run the app.
        Developers will need to check if their own app needs to use SCHEDULE_EXACT_ALARM instead -->
   <uses-permission android:name="android.permission.USE_EXACT_ALARM" />
   <uses-permission android:name="android.permission.POST_NOTIFICATIONS"/>
   <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
   <!-- NOTE: Special use was selected as it's the closest match for this example app.
        apps should specify the appropriate permission for their use cases. -->
   <uses-permission android:name="android.permission.FOREGROUND_SERVICE_SPECIAL_USE" />
   <!-- NOTE: This permission isn't needed by the local notification plugin. It is only being
        requested because the example app will download remote content to demonstrate some scenarios-->
   <uses-permission android:name="android.permission.INTERNET"/>
   <uses-permission android:name="android.permission.ACCESS_NOTIFICATION_POLICY"/>
   <application
        android:label="flutter_local_notifications_example"
        android:icon="@mipmap/ic_launcher">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize"
            android:showWhenLocked="true"
            android:turnScreenOn="true"
            android:exported="true">
            <!-- 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" />
        <!-- If you want your foreground service to be stopped if
             your app is stopped, set android:stopWithTask to true.
             See https://developer.android.com/reference/android/R.attr#stopWithTask -->
        <service
            android:name="com.dexterous.flutterlocalnotifications.ForegroundService"        
            android:exported="false"
            android:stopWithTask="false"
            android:foregroundServiceType="specialUse">
            <property android:name="android.app.PROPERTY_SPECIAL_USE_FGS_SUBTYPE" android:value="To demonstrate how to use foreground services to show notifications"/>
        </service>
        <receiver android:exported="false" android:name="com.dexterous.flutterlocalnotifications.ActionBroadcastReceiver" />
        <receiver android:exported="false" android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationReceiver" />
        <receiver android:exported="false" android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationBootReceiver">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED"/>
                <action android:name="android.intent.action.MY_PACKAGE_REPLACED"/>
                <action android:name="android.intent.action.QUICKBOOT_POWERON" />
                <action android:name="com.htc.intent.action.QUICKBOOT_POWERON"/>
            </intent-filter>
        </receiver>
    </application>
    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
</manifest>

需要增加 WEAK_LOCK权限，

<manifest xmlns:android="http://schemas.android.com/apk/res/android">
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
    <uses-permission android:name="android.permission.VIBRATE" />
    <uses-permission android:name="android.permission.USE_FULL_SCREEN_INTENT" />
    <uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM" />
    <uses-permission android:name="android.permission.POST_NOTIFICATIONS"/>
    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS" />
    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_SPECIAL_USE" />
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_NOTIFICATION_POLICY"/>

    <application
        android:label="flutter_local_notifications_example"
        android:icon="@mipmap/ic_launcher">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize"
            android:showWhenLocked="true"
            android:turnScreenOn="true"
            android:exported="true">
            <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>
        
        <meta-data
            android:name="flutterEmbedding"
            android:value="2" />
            
        <service
            android:name="com.dexterous.flutterlocalnotifications.ForegroundService"        
            android:exported="false"
            android:stopWithTask="false"
            android:foregroundServiceType="specialUse">
            <property android:name="android.app.PROPERTY_SPECIAL_USE_FGS_SUBTYPE" android:value="To demonstrate how to use foreground services to show notifications"/>
        </service>
        
        <receiver 
            android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationReceiver"
            android:exported="false">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED"/>
            </intent-filter>
        </receiver>
        
        <receiver 
            android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationBootReceiver"
            android:exported="false">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED"/>
                <action android:name="android.intent.action.MY_PACKAGE_REPLACED"/>
                <action android:name="android.intent.action.QUICKBOOT_POWERON" />
                <action android:name="com.htc.intent.action.QUICKBOOT_POWERON"/>
                <action android:name="android.intent.action.LOCKED_BOOT_COMPLETED"/>
            </intent-filter>
        </receiver>
    </application>
</manifest>

增加了WAKE_LOCK后，app被杀死后就可以正常显示系统通知消息