在 Android 6 以上的设备中，flutter_local_notifications 未在发布模式下显示前台通知

Question

我正在使用 Firebase Cloud Messaging(FCM) 向我的 Flutter 应用发送推送通知。我需要在 Android 的前台显示通知，所以尝试了 FlutterFire 文档中提到的插件 -flutter_local_notifications，但它似乎不适用于所有设备。我发现它只能在一台运行 Android 6 的设备上运行。

我在AndroidManifest.xml 中添加了这一行 -

  <meta-data
            android:name="com.google.firebase.messaging.high_importance_channel"
            android:value="high_importance_channel"/>

我如何在接收 FCM 消息时触发本地通知 -

 // local notif initialisation //
    var initializationSettingsAndroid = new AndroidInitializationSettings('@mipmap/ic_launcher');
    var initializationSettingsIOS = new IOSInitializationSettings();
    var initializationSettings = new InitializationSettings(android: initializationSettingsAndroid, iOS: initializationSettingsIOS);

    flutterLocalNotificationsPlugin = new FlutterLocalNotificationsPlugin();
    flutterLocalNotificationsPlugin.initialize(initializationSettings, onSelectNotification: onSelectNotification);

    /// Foreground
    FirebaseMessaging.onMessage.listen((RemoteMessage message) {
      if (message.notification != null) {
        print('Foreground (onMessage): Title:${message.notification.title}, Subtitle:${message.notification.body}, Data:${message.data.toString()}');
        remoteMessage = message;
        var data = json.decode(message.data['metadata']);

        showNotification(
          1234,
          "${message.notification.title}",
          "${message.notification.body}",
          "$message",
        );
      }
    });

我也尝试过像这样创建自定义通知通道

  AndroidNotificationChannel channel = AndroidNotificationChannel(
    'high_importance_channel', // id
    'High Importance Notifications', // title
    description: 'This channel is used for important notifications.', // description
    importance: Importance.max,
  );

 await flutterLocalNotificationsPlugin
        .resolvePlatformSpecificImplementation<AndroidFlutterLocalNotificationsPlugin>()
        ?.createNotificationChannel(channel);

我不确定我是否遗漏了什么？更高的 Android API 级别是否有任何额外的步骤。插件的自述文件中有一个标题为Release build configuration 的注释，要求对 ProGuard 文件进行自定义，我也遵循了这些步骤，但对我的情况没有任何帮助。在这个问题上寻求一些帮助。

依赖版本：

  firebase_core: ^1.13.1 
  firebase_messaging: ^11.2.8
  flutter_local_notifications: ^9.2.0

Flutter SDK 版本：Flutter 2.10.2

Answer 1

在androidpp 目录中添加proguard-rules.pro。正如 flutter_location_notification 所暗示的那样

##---------------Begin: proguard configuration for Gson  ----------
# Gson uses generic type information stored in a class file when working with fields. Proguard
# removes such information by default, so configure it to keep all of it.
-keepattributes Signature

# For using GSON @Expose annotation
-keepattributes *Annotation*

# Gson specific classes
-dontwarn sun.misc.**
#-keep class com.google.gson.stream.** { *; }

# Application classes that will be serialized/deserialized over Gson
-keep class com.google.gson.examples.android.model.** { <fields>; }

# Prevent proguard from stripping interface information from TypeAdapter, TypeAdapterFactory,
# JsonSerializer, JsonDeserializer instances (so they can be used in @JsonAdapter)
-keep class * extends com.google.gson.TypeAdapter
-keep class * implements com.google.gson.TypeAdapterFactory
-keep class * implements com.google.gson.JsonSerializer
-keep class * implements com.google.gson.JsonDeserializer

# Prevent R8 from leaving Data object members always null
-keepclassmembers,allowobfuscation class * {
  @com.google.gson.annotations.SerializedName <fields>;
}

# Retain generic signatures of TypeToken and its subclasses with R8 version 3.0 and higher.
-keep,allowobfuscation,allowshrinking class com.google.gson.reflect.TypeToken
-keep,allowobfuscation,allowshrinking class * extends com.google.gson.reflect.TypeToken

##---------------End: proguard configuration for Gson  ----------

您可以尝试在androidppuild.gradle > buildTypes > release 中添加以下行

proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'

buildTypes 将如下所示：

buildTypes {
        release {
            minifyEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile(
                    'proguard-android-optimize.txt'),
                    'proguard-rules.pro'
            signingConfig signingConfigs.release
        }

Answer 2

各位有没有找到解决办法？我也面临同样的问题，我不知道要解决这个问题。