这是一个简单的实现，展示了：
1.将字符串Value从flutter传递到Android代码
1.从Android代码获取响应以进行Flutter
代码基于以下示例：https://flutter.io/platform-channels/#codec
1.传递字符串值“text”：

String text = "whatever";

Future<Null> _getBatteryLevel(text) async {
String batteryLevel;
try {
  final String result = await platform.invokeMethod('getBatteryLevel',{"text":text}); 
  batteryLevel = 'Battery level at $result % .';
} on PlatformException catch (e) {
  batteryLevel = "Failed to get battery level: '${e.message}'.";
}

setState(() {
  _batteryLevel = batteryLevel;
});

1.在RandomFunction（）后返回响应“电池电量”;

public void onMethodCall(MethodCall call, MethodChannel.Result result) {
    if (call.method.equals("getBatteryLevel")) {

        text = call.argument("text");
        String batteryLevel = RandomFunction(text);

        if (batteryLevel != null) {
            result.success(batteryLevel);
        } else {
            result.error("UNAVAILABLE", "Battery level not available.", null);
        }
    } else {
        result.notImplemented();
    }
}

目标C

call.arguments[@"parameter"]

安卓

call.argument("parameter");

是的，flutter确实有一个EventChannel类，这正是您要寻找的。
Here是一个示例，演示了如何实现MethodChannel和EventChannel。this中等文章展示了如何在flutter中实现EventChannel。
希望有帮助！

对于雨燕

guard let args = call.arguments as? [String : Any] else {return}
    let phoneNumber = args["contactNumber"] as! String
    let originalMessage = args["message"] as! String

从Flutter转换为本地：

await platform.invokeMethod('runModel', 
                           {'path': imagePath!.path} // 'path' is the key here to be passed to Native side
);

对于Android（Kotlin）：

val hashMap = call.arguments as HashMap<*,*> //Get the arguments as a HashMap

val path = hashMap["path"] //Get the argument based on the key passed from Flutter

对于iOS（Swift）：

guard let args = call.arguments as? [String : Any] else {return}
let text = args["path"] as! String

如果有人想用invoke方法将数据从native共享到flutter，请执行以下操作：
main.dart

Future<dynamic> handlePlatformChannelMethods() async {
  platform.setMethodCallHandler((methodCall) async {
   if (methodCall.method == "nativeToFlutter") {
     String text = methodCall.arguments;
     List<String> result = text.split(' ');
     String user = result[0];
     String message = result[1];
    }
   }
  }

MainActivity.java

nativeToFlutter(text1:String?,text2:String?){
 MethodChannel(flutterEngine!!.dartExecutor.binaryMessenger, 
  CHANNEL.invokeMethod("nativeToFlutter",text1+" "+text2);
 }