调用函数并将参数从Kotlin传递到Flatter

Question

我正在处理平台频道（PlatformChannels），试图从Kotlin（Kotlin）到Flatter（颤振）进行通信。尝试实际执行颤振平台频道文档中解释的操作，但方向相反：

通道文件颤振平台

其思想是从MainActivity上的ConfigureFlatterEngine函数调用颤振函数。kt级。

为此，我做了，在颤振方面，梅因。dart（颤振的默认示例）：

   class _MyHomePageState extends State<MyHomePage> {

  static const platformChannel = const MethodChannel('myTestChannel');


  @override
  Widget build(BuildContext context) {

    platformChannel.setMethodCallHandler((call){
      print("Hello from ${call.method}");
      return null;
    });


    //
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          //
          //
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
          ],
        ),
      ),
    );
  }
}

从Kotlin方面来说，我只是尝试调用MainActivity上的颤振回调方法。kt:

override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        GeneratedPluginRegistrant.registerWith(flutterEngine)

        val channel = MethodChannel(flutterEngine.dartExecutor.binaryMessenger, "myTestChannel")

        channel.invokeMethod("myTestChannel","the argument from Android")
}

但当我运行代码时，颤振面上没有打印任何内容。也没有崩溃或异常。

Answer 1

这最终在我这边奏效了。如果您想在android生命周期回调中调用您的方法，请尝试以下操作

const val CHANNEL = "yourTestChannel"

class MainActivity : FlutterActivity() {

  override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
    GeneratedPluginRegistrant.registerWith(flutterEngine);
  }

  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    var flutterEngine = FlutterEngine(this)

    flutterEngine
      .dartExecutor
      .executeDartEntrypoint(
        DartExecutor.DartEntrypoint.createDefault()
      )

    var channel = MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL)

    channel.invokeMethod("yourMethod", "yourArguments")
    }
  }
}

Answer 2

你应该按照下面的方式执行

飞镖代码

method_channel_helper.dart

class AmazonFileUpload {
  static const platform = const MethodChannel('amazon');
  static StreamController<String> _controller = StreamController.broadcast();

  static Stream get streamData => _controller.stream;

  Future<BaseResponse> uploadFile() async {
    try {
      platform.setMethodCallHandler((call) {
        switch (call.method) {
          case "callBack":
            _controller.add("");
            break;
        }
      });
      final Map result = await platform.invokeMethod('s3_upload');
      return BaseResponse(result["success"], result["error"], "");
    } on PlatformException catch (e) {
      return BaseResponse(false, e.message, "");
    }
  }
}

主页。飞奔

class _HomePageState extends State<HomePage> {

  @override
  void initState() {
    super.initState();
    AmazonFileUpload.streamData.listen((event) {
      print("========$callbackFromKotlinToDart--------");
    });
    AmazonFileUpload().uploadFile();



  @override
  Widget build(BuildContext context) {

}

Android代码

class MainActivity : FlutterActivity(), TransferListener {
    private val CHANNEL = "amazon"

    var methodResult: MethodChannel.Result? = null
    override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        GeneratedPluginRegistrant.registerWith(flutterEngine);
        val channel = MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL)

        channel.setMethodCallHandler { call, result ->
            methodResult = result
            if (call.method == "s3_upload") {
                //Add you login here 
                channel.invokeMethod("callBack", "data1")



            }
        }

    }