feat(analytics): event bridge common package

packages/mixpanel_flutter/android/build.gradle

@@ -2,6 +2,7 @@ group 'com.mixpanel.mixpanel_flutter'
 version '1.0'
 
 buildscript {
+    ext.kotlin_version = '1.9.0'
     repositories {
         google()
         mavenCentral()
@@ -10,6 +11,7 @@ buildscript {
     dependencies {
         // Use a compatible version of Gradle Plugin
         classpath 'com.android.tools.build:gradle:8.1.0' // Updated to 8.1.0
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
 
@@ -21,6 +23,7 @@ rootProject.allprojects {
 }
 
 apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
 
 android {
     // Safely handle 'namespace' property for new Android Gradle plugin versions
@@ -40,12 +43,26 @@ android {
         targetCompatibility JavaVersion.VERSION_17
     }
 
+    kotlinOptions {
+        jvmTarget = '17'
+    }
+
+    sourceSets {
+        main.kotlin.srcDirs += 'src/main/kotlin'
+    }
+
     lintOptions {
         disable 'InvalidPackage'
     }
 }
 
 dependencies {
-    // Use the Mixpanel Android SDK
     implementation "com.mixpanel.android:mixpanel-android:8.7.0"
+    // mixpanel-android:8.7.0 only declares mixpanel-android-common as a
+    // runtime dependency, so MixpanelEventBridge is not on the compile
+    // classpath unless we add it explicitly here. EventBridgeSubscriber.kt
+    // imports it directly.
+    implementation "com.mixpanel.android:mixpanel-android-common:1.0.1"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.1"
 }

packages/mixpanel_flutter/android/src/main/java/com/mixpanel/mixpanel_flutter/MixpanelFlutterPlugin.java

@@ -201,12 +201,30 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
             case "getAllVariants":
                 handleGetAllVariants(call, result);
                 break;
+            case "startEventBridge":
+                handleStartEventBridge(result);
+                break;
+            case "stopEventBridge":
+                handleStopEventBridge(result);
+                break;
             default:
                 result.notImplemented();
                 break;
         }
     }
 
+    private void handleStartEventBridge(Result result) {
+        if (channel != null) {
+            EventBridgeSubscriber.start(channel);
+        }
+        result.success(null);
+    }
+
+    private void handleStopEventBridge(Result result) {
+        EventBridgeSubscriber.stop();
+        result.success(null);
+    }
+
     private void initializeMethodChannel() {
         if (channel == null && flutterPluginBinding != null) {
             channel = new MethodChannel(flutterPluginBinding.getBinaryMessenger(), "mixpanel_flutter",
@@ -785,6 +803,7 @@ private long readPersistenceTtlMillis(Map<String, Object> policyMap) {
 
     @Override
     public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
+        EventBridgeSubscriber.stop();
         if (channel != null) {
             channel.setMethodCallHandler(null);
             channel = null;

packages/mixpanel_flutter/android/src/main/kotlin/com/mixpanel/mixpanel_flutter/EventBridgeSubscriber.kt

@@ -0,0 +1,62 @@
+package com.mixpanel.mixpanel_flutter
+
+import android.util.Log
+import com.mixpanel.android.eventbridge.MixpanelEventBridge
+import io.flutter.plugin.common.MethodChannel
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.plus
+import org.json.JSONException
+import org.json.JSONObject
+
+/**
+ * Subscribes to the native Mixpanel SDK's [MixpanelEventBridge] (a Kotlin
+ * `SharedFlow`) and forwards each event to the Dart side via the existing
+ * Flutter MethodChannel.
+ *
+ * The Java plugin calls [start] from `onAttachedToEngine` and [stop] from
+ * `onDetachedFromEngine`. This object is a singleton because the native
+ * SharedFlow itself is a singleton — we never want more than one active
+ * subscription per process.
+ */
+object EventBridgeSubscriber {
+
+    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.Main)
+    private var job: Job? = null
+
+    @JvmStatic
+    fun start(channel: MethodChannel) {
+        if (job != null) return
+        job = scope.launch {
+            MixpanelEventBridge.events().collect { event ->
+                val properties = event.properties?.let { safelyConvert(it) }
+                channel.invokeMethod(
+                    "onMixpanelEvent",
+                    mapOf(
+                        "eventName" to event.eventName,
+                        "properties" to properties,
+                    )
+                )
+            }
+        }
+    }
+
+    @JvmStatic
+    fun stop() {
+        job?.cancel()
+        job = null
+    }
+
+    private fun safelyConvert(json: JSONObject): Map<String, Any?>? = try {
+        MixpanelFlutterHelper.toMap(json)
+    } catch (e: JSONException) {
+        // A malformed properties payload should not abort the whole
+        // subscription — drop this event's properties and keep collecting.
+        Log.w("EventBridgeSubscriber", "Failed to convert event properties", e)
+        null
+    }
+}

packages/mixpanel_flutter/example/pubspec.lock

@@ -143,6 +143,13 @@ packages:
       relative: true
     source: path
     version: "2.8.0"
+  mixpanel_flutter_common:
+    dependency: transitive
+    description:
+      path: "../../mixpanel_flutter_common"
+      relative: true
+    source: path
+    version: "0.1.0"
   path:
     dependency: transitive
     description:

packages/mixpanel_flutter/ios/mixpanel_flutter.podspec

@@ -16,6 +16,9 @@ Pod::Spec.new do |s|
   s.source_files = 'Classes/**/*'
   s.dependency 'Flutter'
   s.dependency 'Mixpanel-swift', '6.4.0'
+  # Explicit dependency (also pulled in transitively by Mixpanel-swift 6.4+)
+  # so `import MixpanelSwiftCommon` in our plugin resolves reliably.
+  s.dependency 'MixpanelSwiftCommon', '~> 1.0.0'
   s.platform = :ios, '12.0'
 
   # Flutter.framework does not contain a i386 slice.