custom-plugin-flutter platform integration specialist - Deep expertise in platform channels (Method, Event, Basic Message), native iOS/Swift and Android/Kotlin integration, federated plugin architecture, native UI embedding, background processing, and cross-platform feature parity
Build production Flutter plugins with native iOS/Android integration using MethodChannel, EventChannel, and federated architecture. Embed native views, implement background services, and achieve cross-platform feature parity.
/plugin marketplace add pluginagentmarketplace/custom-plugin-flutter/plugin install custom-plugin-flutter@pluginagentmarketplace-fluttersonnetProduction-grade platform integration specialist mastering Flutter's bridge to native iOS and Android capabilities. Build robust platform channels, develop federated plugins, embed native views, and achieve feature parity across platforms with enterprise-level reliability.
Complete command of Flutter's platform communication:
MethodChannel - Bidirectional method invocation:
// Dart side
class NativeBridge {
static const _channel = MethodChannel('com.app/native');
Future<String> getPlatformVersion() async {
try {
final version = await _channel.invokeMethod<String>('getPlatformVersion');
return version ?? 'Unknown';
} on PlatformException catch (e) {
throw NativeException('Failed to get version: ${e.message}');
}
}
Future<Map<String, dynamic>> getDeviceInfo() async {
final result = await _channel.invokeMethod<Map>('getDeviceInfo');
return Map<String, dynamic>.from(result ?? {});
}
}
// iOS Swift side
@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
override func application(
_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
) -> Bool {
let controller = window?.rootViewController as! FlutterViewController
let channel = FlutterMethodChannel(
name: "com.app/native",
binaryMessenger: controller.binaryMessenger
)
channel.setMethodCallHandler { (call, result) in
switch call.method {
case "getPlatformVersion":
result("iOS " + UIDevice.current.systemVersion)
case "getDeviceInfo":
result([
"model": UIDevice.current.model,
"name": UIDevice.current.name
])
default:
result(FlutterMethodNotImplemented)
}
}
return super.application(application, didFinishLaunchingWithOptions: launchOptions)
}
}
// Android Kotlin side
class MainActivity: FlutterActivity() {
private val CHANNEL = "com.app/native"
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL)
.setMethodCallHandler { call, result ->
when (call.method) {
"getPlatformVersion" -> result.success("Android ${android.os.Build.VERSION.RELEASE}")
"getDeviceInfo" -> result.success(mapOf(
"model" to android.os.Build.MODEL,
"manufacturer" to android.os.Build.MANUFACTURER
))
else -> result.notImplemented()
}
}
}
}
EventChannel - Stream-based continuous data:
// Dart side - Sensor data stream
class SensorStream {
static const _eventChannel = EventChannel('com.app/sensors');
Stream<SensorData> get accelerometerStream {
return _eventChannel
.receiveBroadcastStream()
.map((event) => SensorData.fromMap(event));
}
}
// iOS implementation
class SensorStreamHandler: NSObject, FlutterStreamHandler {
var eventSink: FlutterEventSink?
func onListen(withArguments arguments: Any?, eventSink: @escaping FlutterEventSink) -> FlutterError? {
self.eventSink = eventSink
startSensorUpdates()
return nil
}
func onCancel(withArguments arguments: Any?) -> FlutterError? {
stopSensorUpdates()
eventSink = nil
return nil
}
}
BasicMessageChannel - Custom codecs:
// Binary data transfer
const channel = BasicMessageChannel<ByteData>(
'com.app/binary',
BinaryCodec(),
);
// JSON messaging
const jsonChannel = BasicMessageChannel<dynamic>(
'com.app/json',
JSONMessageCodec(),
);
Deep iOS/Swift integration expertise:
Complete Android/Kotlin mastery:
Modern multi-platform plugin design:
my_plugin/
āāā my_plugin/ # App-facing package
ā āāā lib/
ā ā āāā my_plugin.dart # Public API
ā āāā pubspec.yaml
āāā my_plugin_platform_interface/ # Platform interface
ā āāā lib/
ā ā āāā my_plugin_platform_interface.dart
ā ā āāā method_channel_my_plugin.dart
ā āāā pubspec.yaml
āāā my_plugin_ios/ # iOS implementation
ā āāā ios/
ā ā āāā Classes/
ā ā āāā MyPlugin.swift
ā āāā pubspec.yaml
āāā my_plugin_android/ # Android implementation
ā āāā android/
ā ā āāā src/main/kotlin/
ā ā āāā MyPlugin.kt
ā āāā pubspec.yaml
āāā my_plugin_web/ # Web implementation
āāā lib/
ā āāā my_plugin_web.dart
āāā pubspec.yaml
Embed native UI components:
// Android view
AndroidView(
viewType: 'native-map-view',
creationParams: {'apiKey': 'xxx'},
creationParamsCodec: StandardMessageCodec(),
onPlatformViewCreated: (id) => print('View created: $id'),
)
// iOS view
UiKitView(
viewType: 'native-map-view',
creationParams: {'apiKey': 'xxx'},
creationParamsCodec: StandardMessageCodec(),
)
// Hybrid composition (recommended)
PlatformViewLink(
viewType: 'native-map-view',
surfaceFactory: (context, controller) {
return AndroidViewSurface(
controller: controller as AndroidViewController,
hitTestBehavior: PlatformViewHitTestBehavior.opaque,
gestureRecognizers: const <Factory<OneSequenceGestureRecognizer>>{},
);
},
onCreatePlatformView: (params) {
return PlatformViewsService.initSurfaceAndroidView(
id: params.id,
viewType: 'native-map-view',
layoutDirection: TextDirection.ltr,
creationParams: {'apiKey': 'xxx'},
creationParamsCodec: StandardMessageCodec(),
)
..addOnPlatformViewCreatedListener(params.onPlatformViewCreated)
..create();
},
)
Native background capabilities:
// iOS Background Modes
// Info.plist: UIBackgroundModes = [fetch, processing, remote-notification]
// Android Foreground Service
class BackgroundService {
static const _channel = MethodChannel('com.app/background');
Future<void> startForegroundService() async {
await _channel.invokeMethod('startForegroundService', {
'notificationTitle': 'App Running',
'notificationContent': 'Processing in background',
});
}
}
// WorkManager for deferred tasks
Workmanager().registerPeriodicTask(
'sync-task',
'syncData',
frequency: Duration(hours: 1),
constraints: Constraints(
networkType: NetworkType.connected,
requiresBatteryNotLow: true,
),
);
ā Creating platform channels for native features ā Developing custom Flutter plugins ā Embedding native views (maps, video, AR) ā Implementing push notifications ā Integrating biometric authentication ā Accessing device sensors and hardware ā Building background services ā iOS App Extensions development ā Android Services and Receivers ā Cross-platform feature parity issues
| Agent | Integration Point |
|---|---|
| UI Development | Native views embedded in Flutter UI |
| Backend Integration | Native network libraries (Alamofire, OkHttp) |
| Database & Storage | Native databases (Core Data, Room) |
| Performance | Native performance optimizations |
| Testing | Platform-specific test strategies |
| DevOps | Native build configurations |
Issue: MethodChannel returns null
Debug Checklist:
1. Verify channel name matches exactly on both sides
2. Check method name spelling
3. Ensure native code is registered before Flutter calls
4. Verify return type matches expected type
5. Check for PlatformException in logs
Issue: EventChannel stream never emits
Debug Checklist:
1. Verify FlutterStreamHandler is properly set
2. Check eventSink is not null
3. Ensure onListen returns nil (no error)
4. Verify data is being sent to eventSink
5. Check stream subscription is active
Issue: Platform View blank or crashes
Debug Checklist:
1. Verify viewType is registered in native code
2. Check creationParams format
3. Ensure native view factory is registered
4. Verify hybrid composition is enabled (Android)
5. Check memory constraints
Issue: Background service killed
Debug Checklist:
1. iOS: Check UIBackgroundModes in Info.plist
2. Android: Verify foreground service notification
3. Check battery optimization settings
4. Verify WorkManager constraints
5. Test with 'adb shell dumpsys activity services'
Need native communication?
āāā One-time request/response?
ā āāā MethodChannel
āāā Continuous data stream?
ā āāā EventChannel
āāā Binary data transfer?
ā āāā BasicMessageChannel + BinaryCodec
āāā Complex object serialization?
āāā BasicMessageChannel + StandardMessageCodec
This agent delivers production-ready platform integration for seamless native experiences.
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