platform-handler

name	platform_handler
description	Use when coding with platform_handler: centralized Flutter MethodChannel registration, native-to-Flutter notification dispatch, invokeMethod wrappers, and PingPongPlatformNotification requestId response matching.

platform_handler Agent Context

Use this package to organize Flutter MethodChannel communication. Register a channel once, subscribe notifications by native method name, and invoke native methods through a PlatformHandler.

Imports

import 'package:platform_handler/platform_handler.dart';
import 'package:platform_handler/platform_notification.dart';

Handler Setup

class AppPlatformHandler extends PlatformHandler {
  @override
  Future<dynamic> n2fCallDispatcher(MethodCall call) async {
    print("native -> flutter: ${call.method}, ${call.arguments}");
    return super.n2fCallDispatcher(call);
  }
}

final handler = AppPlatformHandler();
handler.registerChannel("native.demo.com/messageChannel");

Native Callback Notification

class LogNotification extends PlatformNotification {
  LogNotification() {
    subscribers = {
      "LogCallback": onLog,
    };
  }

  void listen() {
    docking = true;
  }

  void onLog(dynamic arguments) {
    print(arguments);
  }
}

final logNotification = LogNotification()..listen();
handler.subscribe([logNotification]);
await handler.invokeMethod("startLog");

Ping-Pong Request/Response

Use PingPongPlatformNotification when each request expects one matching terminal response.

class RuleNotification extends PingPongPlatformNotification {
  RuleNotification() {
    subscribers = {
      "RuleResult": onRuleResult,
    };
  }

  void listen() {
    docking = true;
  }

  void onRuleResult(dynamic responseData) {
    print("rule result: $responseData");
  }
}

final ruleNotification = RuleNotification()..listen();
handler.subscribe([ruleNotification]);
await handler.invokeMethod("luaScript", "return 1", ruleNotification);

Native must respond with { "requestId": sameRequestId, "responseData": result }. Late, duplicate, or mismatched request IDs are ignored.

Notes for Agents

• Business code should use handler.invokeMethod, not raw MethodChannel, unless low-level control is required.
• Set docking = true before expecting callbacks.
• Map native method names in subscribers.
• Use PingPongPlatformNotification for request-response flows; use PlatformNotification for push/event callbacks.