How to pass arguments from Flutter to Kotlin?

Question

i've got started studying Flutter. I'm trying to using MethodChannel and MethodCall to communicate with Android platform. I don't know how to pass arguments to the Android code.

Below is my code.

// dart
void _onClick() async {
    var parameters = {'image':'starry night'};
    await platform.invokeMethod('showToast', new Map.from(parameters));
}


// kotlin
MethodChannel(flutterView, CHANNEL).setMethodCallHandler { call, result ->
    Log.d("MainActivity", ">> ${call.method}, ${call.arguments}")
    when (call.method) {
        "showToast" -> {
        showToast("toast")
    }
    else -> {
        Log.d("MainActivity", "fail");
    }
}

I can check an arguement value what I passed by log message what I printed. {image=starry night} But I don't know how to parse to a map object.

Answer 1

Flutter

On the Flutter side, you can pass arguments by including them as a map in the invokeMethod call.

_channel.invokeMethod('showToast', {'text': 'hello world'});

Kotlin

On the Kotlin side you can get the parameters by casting call.arguments as a Map or getting a particular argument from call.argument().

override fun onMethodCall(call: MethodCall, result: Result) {
  when (call.method) {
    "showToast" -> {
      val text = call.argument<String>("text") // hello world
      showToast(text)
    }   
  }
}