How to get context and activity

package com.example.fluttertoast

import android.app.Activity
import android.content.Context
import android.widget.Toast
import androidx.annotation.NonNull;

import io.flutter.embedding.engine.plugins.FlutterPlugin
import io.flutter.embedding.engine.plugins.activity.ActivityAware
import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding
import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel
import io.flutter.plugin.common.MethodChannel.MethodCallHandler
import io.flutter.plugin.common.MethodChannel.Result
import io.flutter.plugin.common.PluginRegistry.Registrar

/** FluttertoastPlugin */
class FluttertoastPlugin: FlutterPlugin, MethodCallHandler, ActivityAware {
  private lateinit var channel : MethodChannel
  private lateinit var activity:Activity
  private lateinit var context: Context

  override fun onAttachedToEngine(@NonNull flutterPluginBinding: FlutterPlugin.FlutterPluginBinding) {
    channel = MethodChannel(flutterPluginBinding.flutterEngine.dartExecutor, "fluttertoast")
    channel.setMethodCallHandler(this)
    this.context = flutterPluginBinding.applicationContext
  }

  companion object {
    @JvmStatic
    fun registerWith(registrar: Registrar) {
      val channel = MethodChannel(registrar.messenger(), "fluttertoast")
      channel.setMethodCallHandler(FluttertoastPlugin())
    }
  }

  override fun onMethodCall(@NonNull call: MethodCall, @NonNull result: Result) {
    if (call.method == "getPlatformVersion") {
      Toast.makeText(activity,"Hello!",Toast.LENGTH_SHORT).show()
      result.success("Android ${android.os.Build.VERSION.RELEASE}")
    } else {
      result.notImplemented()
    }
  }

  override fun onDetachedFromEngine(@NonNull binding: FlutterPlugin.FlutterPluginBinding) {
    channel.setMethodCallHandler(null)
  }
  override fun onDetachedFromActivity() {}
  override fun onReattachedToActivityForConfigChanges(binding: ActivityPluginBinding) {
    onAttachedToActivity(binding)
  }
  override fun onAttachedToActivity(binding: ActivityPluginBinding) {
    this.activity = binding.activity
  }
  override fun onDetachedFromActivityForConfigChanges() {}
}