refactor(messaging, android): removed unsafe & deprecated API. E.g. LocalBroadcastManager replaced by LiveData

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/FlutterFirebaseMessagingBackgroundService.java

@@ -14,6 +14,7 @@
 import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Objects;
 import java.util.concurrent.CountDownLatch;
 
 public class FlutterFirebaseMessagingBackgroundService extends JobIntentService {
@@ -29,8 +30,10 @@ public class FlutterFirebaseMessagingBackgroundService extends JobIntentService
    * Schedule the message to be handled by the {@link FlutterFirebaseMessagingBackgroundService}.
    */
   public static void enqueueMessageProcessing(Context context, Intent messageIntent) {
-    RemoteMessage message = (RemoteMessage) messageIntent.getExtras().get("notification");
+    RemoteMessage message =
+        (RemoteMessage) Objects.requireNonNull(messageIntent.getExtras()).get("notification");
 
+    assert message != null;
     enqueueWork(
         context,
         FlutterFirebaseMessagingBackgroundService.class,

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/FlutterFirebaseMessagingPlugin.java

@@ -8,17 +8,15 @@
 
 import android.Manifest;
 import android.app.Activity;
-import android.content.BroadcastReceiver;
-import android.content.Context;
 import android.content.Intent;
-import android.content.IntentFilter;
 import android.content.pm.PackageManager;
 import android.os.Build;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 import androidx.core.app.NotificationManagerCompat;
-import androidx.localbroadcastmanager.content.LocalBroadcastManager;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.Observer;
 import com.google.android.gms.tasks.Task;
 import com.google.android.gms.tasks.TaskCompletionSource;
 import com.google.android.gms.tasks.Tasks;
@@ -41,7 +39,7 @@
 import java.util.Objects;
 
 /** FlutterFirebaseMessagingPlugin */
-public class FlutterFirebaseMessagingPlugin extends BroadcastReceiver
+public class FlutterFirebaseMessagingPlugin
     implements FlutterFirebasePlugin,
         MethodCallHandler,
         NewIntentListener,
@@ -52,6 +50,12 @@ public class FlutterFirebaseMessagingPlugin extends BroadcastReceiver
   private MethodChannel channel;
   private Activity mainActivity;
 
+  private final LiveData<RemoteMessage> liveDataRemoteMessage =
+      FlutterFirebaseRemoteMessageLiveData.getInstance();
+  private Observer<RemoteMessage> remoteMessageObserver;
+  private final LiveData<String> liveDataToken = FlutterFirebaseTokenLiveData.getInstance();
+  private Observer<String> tokenObserver;
+
   private RemoteMessage initialMessage;
   // We store the initial notification in a separate variable
   // because we cannot set the notification key in
@@ -65,13 +69,18 @@ private void initInstance(BinaryMessenger messenger) {
     channel = new MethodChannel(messenger, channelName);
     channel.setMethodCallHandler(this);
     permissionManager = new FlutterFirebasePermissionManager();
-    // Register broadcast receiver
-    IntentFilter intentFilter = new IntentFilter();
-    intentFilter.addAction(FlutterFirebaseMessagingUtils.ACTION_TOKEN);
-    intentFilter.addAction(FlutterFirebaseMessagingUtils.ACTION_REMOTE_MESSAGE);
-    LocalBroadcastManager manager =
-        LocalBroadcastManager.getInstance(ContextHolder.getApplicationContext());
-    manager.registerReceiver(this, intentFilter);
+
+    remoteMessageObserver =
+        remoteMessage -> {
+          Map<String, Object> content =
+              FlutterFirebaseMessagingUtils.remoteMessageToMap(remoteMessage);
+          channel.invokeMethod("Messaging#onMessage", content);
+        };
+    tokenObserver = token -> channel.invokeMethod("Messaging#onTokenRefresh", token);
+    // We remove these observers in the onDetachedFromEngine method. Using "observeForever()"
+    // allows us to use without a LifecycleOwner.
+    liveDataRemoteMessage.observeForever(remoteMessageObserver);
+    liveDataToken.observeForever(tokenObserver);
 
     registerPlugin(channelName, this);
   }
@@ -83,7 +92,8 @@ public void onAttachedToEngine(FlutterPluginBinding binding) {
 
   @Override
   public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
-    LocalBroadcastManager.getInstance(binding.getApplicationContext()).unregisterReceiver(this);
+    liveDataToken.removeObserver(tokenObserver);
+    liveDataRemoteMessage.removeObserver(remoteMessageObserver);
   }
 
   @Override
@@ -115,33 +125,6 @@ public void onDetachedFromActivity() {
     this.mainActivity = null;
   }
 
-  // BroadcastReceiver implementation.
-  @Override
-  public void onReceive(Context context, Intent intent) {
-    String action = intent.getAction();
-
-    if (action == null) {
-      return;
-    }
-
-    if (action.equals(FlutterFirebaseMessagingUtils.ACTION_TOKEN)) {
-      String token = intent.getStringExtra(FlutterFirebaseMessagingUtils.EXTRA_TOKEN);
-      channel.invokeMethod("Messaging#onTokenRefresh", token);
-    } else if (action.equals(FlutterFirebaseMessagingUtils.ACTION_REMOTE_MESSAGE)) {
-      RemoteMessage message;
-      if (android.os.Build.VERSION.SDK_INT >= 33) {
-        message =
-            intent.getParcelableExtra(
-                FlutterFirebaseMessagingUtils.EXTRA_REMOTE_MESSAGE, RemoteMessage.class);
-      } else {
-        message = intent.getParcelableExtra(FlutterFirebaseMessagingUtils.EXTRA_REMOTE_MESSAGE);
-      }
-      if (message == null) return;
-      Map<String, Object> content = FlutterFirebaseMessagingUtils.remoteMessageToMap(message);
-      channel.invokeMethod("Messaging#onMessage", content);
-    }
-  }
-
   private Task<Void> deleteToken() {
     TaskCompletionSource<Void> taskCompletionSource = new TaskCompletionSource<>();
 
@@ -216,7 +199,9 @@ private Task<Void> unsubscribeFromTopic(Map<String, Object> arguments) {
 
     return taskCompletionSource.getTask();
   }
-
+  // This API will be removed in a future release. Slated to be removed by June 2024 by Firebase.
+  // https://firebase.google.com/docs/reference/android/com/google/firebase/messaging/FirebaseMessaging#send
+  @SuppressWarnings("deprecation")
   private Task<Void> sendMessage(Map<String, Object> arguments) {
     TaskCompletionSource<Void> taskCompletionSource = new TaskCompletionSource<>();
 
@@ -383,9 +368,8 @@ private Task<Map<String, Integer>> requestPermissions() {
                     permissions.put("authorizationStatus", notificationsEnabled);
                     taskCompletionSource.setResult(permissions);
                   },
-                  (String errorDescription) -> {
-                    taskCompletionSource.setException(new Exception(errorDescription));
-                  });
+                  (String errorDescription) ->
+                      taskCompletionSource.setException(new Exception(errorDescription)));
             } else {
               permissions.put("authorizationStatus", 1);
               taskCompletionSource.setResult(permissions);
@@ -413,14 +397,14 @@ private Task<Map<String, Integer>> getPermissions() {
         () -> {
           try {
             final Map<String, Integer> permissions = new HashMap<>();
+            final boolean areNotificationsEnabled;
             if (Build.VERSION.SDK_INT >= 33) {
-              final boolean areNotificationsEnabled = checkPermissions();
-              permissions.put("authorizationStatus", areNotificationsEnabled ? 1 : 0);
+              areNotificationsEnabled = checkPermissions();
             } else {
-              final boolean areNotificationsEnabled =
+              areNotificationsEnabled =
                   NotificationManagerCompat.from(mainActivity).areNotificationsEnabled();
-              permissions.put("authorizationStatus", areNotificationsEnabled ? 1 : 0);
             }
+            permissions.put("authorizationStatus", areNotificationsEnabled ? 1 : 0);
             taskCompletionSource.setResult(permissions);
           } catch (Exception e) {
             taskCompletionSource.setException(e);
@@ -445,22 +429,28 @@ public void onMethodCall(final MethodCall call, @NonNull final Result result) {
         @SuppressWarnings("unchecked")
         Map<String, Object> arguments = ((Map<String, Object>) call.arguments);
 
-        long pluginCallbackHandle = 0;
-        long userCallbackHandle = 0;
+        long pluginCallbackHandle;
+        long userCallbackHandle;
 
         Object arg1 = arguments.get("pluginCallbackHandle");
         Object arg2 = arguments.get("userCallbackHandle");
 
         if (arg1 instanceof Long) {
           pluginCallbackHandle = (Long) arg1;
-        } else {
+        } else if (arg1 instanceof Integer) {
           pluginCallbackHandle = Long.valueOf((Integer) arg1);
+        } else {
+          throw new IllegalArgumentException(
+              "Expected 'Long' or 'Integer' type for 'pluginCallbackHandle'.");
         }
 
         if (arg2 instanceof Long) {
           userCallbackHandle = (Long) arg2;
-        } else {
+        } else if (arg2 instanceof Integer) {
           userCallbackHandle = Long.valueOf((Integer) arg2);
+        } else {
+          throw new IllegalArgumentException(
+              "Expected 'Long' or 'Integer' type for 'userCallbackHandle'.");
         }
 
         FlutterShellArgs shellArgs = null;
@@ -546,8 +536,8 @@ private Map<String, Object> getExceptionDetails(@Nullable Exception exception) {
   }
 
   @Override
-  public boolean onNewIntent(Intent intent) {
-    if (intent == null || intent.getExtras() == null) {
+  public boolean onNewIntent(@NonNull Intent intent) {
+    if (intent.getExtras() == null) {
       return false;
     }
 

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/FlutterFirebaseMessagingReceiver.java

@@ -8,7 +8,6 @@
 import android.content.Context;
 import android.content.Intent;
 import android.util.Log;
-import androidx.localbroadcastmanager.content.LocalBroadcastManager;
 import com.google.firebase.messaging.RemoteMessage;
 import java.util.HashMap;
 
@@ -42,9 +41,7 @@ public void onReceive(Context context, Intent intent) {
     //      App in Foreground
     //   ------------------------
     if (FlutterFirebaseMessagingUtils.isApplicationForeground(context)) {
-      Intent onMessageIntent = new Intent(FlutterFirebaseMessagingUtils.ACTION_REMOTE_MESSAGE);
-      onMessageIntent.putExtra(FlutterFirebaseMessagingUtils.EXTRA_REMOTE_MESSAGE, remoteMessage);
-      LocalBroadcastManager.getInstance(context).sendBroadcast(onMessageIntent);
+      FlutterFirebaseRemoteMessageLiveData.getInstance().postRemoteMessage(remoteMessage);
       return;
     }
 

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/FlutterFirebaseMessagingService.java

@@ -4,18 +4,14 @@
 
 package io.flutter.plugins.firebase.messaging;
 
-import android.content.Intent;
 import androidx.annotation.NonNull;
-import androidx.localbroadcastmanager.content.LocalBroadcastManager;
 import com.google.firebase.messaging.FirebaseMessagingService;
 import com.google.firebase.messaging.RemoteMessage;
 
 public class FlutterFirebaseMessagingService extends FirebaseMessagingService {
   @Override
   public void onNewToken(@NonNull String token) {
-    Intent onMessageIntent = new Intent(FlutterFirebaseMessagingUtils.ACTION_TOKEN);
-    onMessageIntent.putExtra(FlutterFirebaseMessagingUtils.EXTRA_TOKEN, token);
-    LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(onMessageIntent);
+    FlutterFirebaseTokenLiveData.getInstance().postToken(token);
   }
 
   @Override

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/FlutterFirebaseRemoteMessageLiveData.java

@@ -0,0 +1,23 @@
+// Copyright 2023 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.firebase.messaging;
+
+import androidx.lifecycle.LiveData;
+import com.google.firebase.messaging.RemoteMessage;
+
+public class FlutterFirebaseRemoteMessageLiveData extends LiveData<RemoteMessage> {
+  private static FlutterFirebaseRemoteMessageLiveData instance;
+
+  public static FlutterFirebaseRemoteMessageLiveData getInstance() {
+    if (instance == null) {
+      instance = new FlutterFirebaseRemoteMessageLiveData();
+    }
+    return instance;
+  }
+
+  public void postRemoteMessage(RemoteMessage remoteMessage) {
+    postValue(remoteMessage);
+  }
+}

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/FlutterFirebaseTokenLiveData.java

@@ -0,0 +1,22 @@
+// Copyright 2023 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.firebase.messaging;
+
+import androidx.lifecycle.LiveData;
+
+public class FlutterFirebaseTokenLiveData extends LiveData<String> {
+  private static FlutterFirebaseTokenLiveData instance;
+
+  public static FlutterFirebaseTokenLiveData getInstance() {
+    if (instance == null) {
+      instance = new FlutterFirebaseTokenLiveData();
+    }
+    return instance;
+  }
+
+  public void postToken(String token) {
+    postValue(token);
+  }
+}

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/JobIntentService.java

@@ -26,6 +26,8 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 
+// Issue added for this file, we will migrate this in the future
+@SuppressWarnings("all")
 abstract class JobIntentService extends Service {
   static final String TAG = "JobIntentService";
 

packages/firebase_messaging/firebase_messaging/example/android/app/build.gradle

@@ -26,7 +26,7 @@ apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
     namespace 'io.flutter.plugins.firebase.messaging.example'
-    compileSdkVersion 33
+    compileSdk 33
 
     lintOptions {
         disable 'InvalidPackage'

packages/firebase_messaging/firebase_messaging/example/android/build.gradle

@@ -1,20 +1,29 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.4.1'
-        classpath 'com.google.gms:google-services:4.3.15'
+        classpath 'com.android.tools.build:gradle:8.1.0'
+        classpath 'com.google.gms:google-services:4.4.0'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
+// Use this to lint the project
+//    gradle.projectsEvaluated {
+//      tasks.withType(JavaCompile).tap {
+//        configureEach {
+//          options.compilerArgs << "-Xlint:deprecation"
+//          options.compilerArgs << "-Xlint:unchecked"
+//        }
+//      }
+//    }
 }
 
 rootProject.buildDir = '../build'

packages/firebase_messaging/firebase_messaging/example/android/gradle.properties

@@ -1,6 +1,5 @@
 org.gradle.jvmargs=-Xmx1536M
 android.useAndroidX=true
-android.enableJetifier=true
 android.defaults.buildfeatures.buildconfig=true
 android.nonTransitiveRClass=false
-android.nonFinalResIds=false
+android.nonFinalResIds=false

packages/firebase_messaging/firebase_messaging/lib/src/messaging.dart

@@ -203,6 +203,9 @@ class FirebaseMessaging extends FirebasePluginPlatform {
   }
 
   /// Send a new [RemoteMessage] to the FCM server. Android only.
+  /// Firebase will decommission in June 2024: https://firebase.google.com/docs/reference/android/com/google/firebase/messaging/FirebaseMessaging#send
+  @Deprecated(
+      'This will be removed in a future release. Firebase will decommission in June 2024')
   Future<void> sendMessage({
     String? to,
     Map<String, String>? data,