platform_handler

A small Flutter helper for organizing native MethodChannel callbacks.

platform_handler lets you register one native channel, subscribe callback handlers by method name, and invoke native methods through the same manager. For request-response style calls, PingPongPlatformNotification automatically attaches a requestId and ignores stale or duplicated responses.

Chinese documentation: README-zh.md

Features

Register a native MethodChannel in one place.
Route native callbacks to focused PlatformNotification classes.
Invoke native methods without exposing MethodChannel to business code.
Built-in ping-pong request id handling for one request and one terminal response.

Quick Start

final handler = AppPlatformHandler();

handler.registerChannel('native.demo.com/messageChannel');
handler.subscribe([
  logNotification,
  ruleNotification,
]);

Handle Native Callbacks

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

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

  void listen() {
    docking = true;
  }

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

Invoke Native Methods

logNotification.listen();
await handler.invokeMethod('startLog');

Ping-Pong Requests

Use PingPongPlatformNotification when each request should accept only one 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();
ruleNotification.listen();

await handler.invokeMethod(
  'luaScript',
  'return 1',
  ruleNotification,
);

When the notification is ping-pong, invokeMethod sends this shape to native:

{
  'requestId': 'ph-request...',
  'arguments': originalArguments,
}

Native should return:

{
  'requestId': sameRequestId,
  'responseData': nativeResult,
}

Only the matching response is delivered to onRuleResult. Late, duplicated, or mismatched responses are ignored.

Native Side

Use the same method channel name on Android and iOS:

native.demo.com/messageChannel

Then call Flutter with the method names subscribed by your notifications, for example LogCallback or RuleResult.

Additional Information

Issues and suggestions are welcome on GitHub.