如何正确地将数据从Android发送到Flutter？

Question

I'm trying to send data back and forth from Flutter to my native platform (in this case Android). In order to keep some model consistency, I have generated the models for all platforms by using Protocol-Buffers.

When I try to pass data from Android to Flutter I'm not finding any way to do it without shenanigans like serializing to a handcrafted JSON.

There must be a way to use protobuf in order to do so, isn't it?

In order to give context, I have made a minimal app to try to solve this problem:

My Protocol Buffer

syntax = "proto3";

option java_package = "com.test.protobuf_test";
option java_outer_classname = "ProtoModel";

message SimplePerson {
    int32 id= 1;
    string name= 2;
}

From which I generate my model using: protoc --java_out and protoc --dart_out

In Dart I get my class

class SimplePerson extends $pb.GeneratedMessage {...}

And in Java

public final class ProtoModel {
...
  public  static final class SimplePerson extends
      com.google.protobuf.GeneratedMessageV3 implements
      SimplePersonOrBuilder {...}
}

From Android inside my method channel, I am trying to pass one or many ProtoModel.SimplePerson objects back to Dart.

No success so far.

How would you actually do it? I'd expect it to be something like In Java:

ProtoModel.SimplePerson person = ProtoModel.SimplePerson.newBuilder().setId(3).setName("Person Name").build();
result(person);

And in Dart:

var result = await platform.invokeMethod("generatePerson");
if(result is SimplePerson) {
  print("Success!");
} else {
  print("Failure!");
}

So far I'm only getting Failures or Exceptions.

Thanks!

Answer 1

your very close your using result but i have it working with result.success

when (call.method) {
    "getPlatformVersion" -> result.success(getPlatformVersion().toByteArray())
}



private fun getPlatformVersion(): Models.Version {
    return Models.Version.newBuilder().setVersionName("Android ${android.os.Build.VERSION.RELEASE}").build()
}

great example here https://www.freecodecamp.org/news/flutter-platform-channels-with-protobuf-e895e533dfb7/

EDIT didnt see how old this post was I have to use this as Pigeon is sill early access, and although pigeon was generally harder to set up i do prefer it