MethodChannel - 在频道上找不到方法的实现

Question

我正在尝试在 Android 和我的 Flutter 项目之间创建一个方法通道，但它不断抛出“缺少插件异常”。尝试清洁，重新安装等，但它不起作用。虽然它适用于我的其他项目。

在 Flutter 方面：

static const platform = const MethodChannel('channel');

按钮按下事件：

  try {
        final int result =
        await platform.invokeMethod('payment');
        print(result);
     } catch (e) {
       print(e.message);
      }

安卓端：

import androidx.annotation.NonNull
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodChannel


class MainActivity: FlutterActivity() {
    private val channel = "channel"
    override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        MethodChannel(flutterEngine.dartExecutor.binaryMessenger, channel).setMethodCallHandler {
            call, result ->
            // Note: this method is invoked on the main thread.
            // TODO
            if (call.method == "payment") {
                result.success(1)
            } else {
                result.notImplemented()
            }
        }
    }
}

异常：

No implementation found for method payment on channel channel