在Flutter应用程序中创建广播接收器，并在Flutter应用程序启动时注册它。当从Android原生应用程序发送意图时，Flutter应用程序将在前台，因此，将执行接收器并自动处理意图。

示例代码：

Flutter应用程序中的广播接收器：

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();

  static const MethodChannel _channel =
      const MethodChannel('com.example/share_intent');

  static Future startReceiver() async {
    _channel.setMethodCallHandler((MethodCall call) async {
      if (call.method == 'onReceive') {
        String text = call.arguments;
        // Do something with the received text
      }
    });
  }
}

class _MyAppState extends State {
  @override
  void initState() {
    super.initState();
    MyApp.startReceiver();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Share Intent Receiver'),
        ),
        body: Center(
          child: const Text('Waiting for text...'),
        ),
      ),
    );
  }
}

在Android Manifest中添加intent-filter：

在MainActivity中发送共享意图：

private void shareText(String text) {
  Intent intent = new Intent(Intent.ACTION_SEND);
  intent.setType("text/plain");
  intent.putExtra(Intent.EXTRA_TEXT, text);
  String packageName = "com.example.flutter_app";
  String className = "com.example.flutter_app.MainActivity";
  intent.setClassName(packageName, className);
  startActivity(intent);
}

在Flutter应用