FlutterDialogBox.java

package adhoc.successive.com.flutteralertdemo;

import android.app.Activity;
import android.app.Dialog;

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;

/** FlutterAlertDemoPlugin */
public class FlutterAlertDemoPlugin implements MethodCallHandler {
 /** Plugin registration. */
 Activity context;
 MethodChannel methodChannel;

 public static void registerWith(Registrar registrar) {
   final MethodChannel channel = new MethodChannel(registrar.messenger(), "flutter_alert_demo");
   channel.setMethodCallHandler(new FlutterAlertDemoPlugin(registrar.activity(), channel));
 }

 public FlutterAlertDemoPlugin(Activity activity, MethodChannel methodChannel) {
   this.context = activity;
   this.methodChannel = methodChannel;
   this.methodChannel.setMethodCallHandler(this);
 }

 @Override
 public void onMethodCall(MethodCall call, Result result) {
   if (call.method.equals("getPlatformVersion")) {
     result.success("Android " + android.os.Build.VERSION.RELEASE);
   }
   else if(call.method.equalsIgnoreCase("showAlertDialog")) {
     Dialog dialog=new Dialog(context);
     dialog.setTitle("Hi, My Name is Flutter");
     dialog.show();
   }
   else {
     result.notImplemented();
   }
 }
}