[BUG | QUESTION] Problems with using SDK with flutter

[amentone]

Device

• I'm using myPOS Smart N5 with Android 5.1.1

SDK Version

• com.mypos:mypossmartsdk:1.0.4

Is your question related to a problem? Please describe.
I'm developing a flutter plugin library in order to use your myPOS Smart SDK in a flutter application.
I've found some problem when I was using your API for Payment and Refund features.
In particular, when I try to handle the activity result with a callback, I can't send the result to Flutter because when I call result.success(resultStatus) I get a black screen on my application without any error.

Flutter Plugin for myPOS

package com.anmentone.my_poster;

import androidx.annotation.NonNull;

import io.flutter.embedding.engine.plugins.FlutterPlugin;
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;
import com.mypos.smartsdk.*;
import android.app.Activity;
import android.content.Intent;
import android.content.res.Configuration;
import android.os.Bundle;
import android.content.Context;
import android.app.Activity;
import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.engine.plugins.activity.ActivityAware;
import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding;

public class MyPosterPlugin implements FlutterPlugin, MethodCallHandler, ActivityAware {
    private MethodChannel channel;
    private Context context;
    private Activity activity;
    private Result result;
    private int resultStatus = -1;

    @Override
    public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {
        context = flutterPluginBinding.getApplicationContext();
        channel = new MethodChannel(flutterPluginBinding.getBinaryMessenger(), "my_poster");
        channel.setMethodCallHandler(this);
    }

    @Override
    public void onAttachedToActivity(ActivityPluginBinding binding) {
        activity = binding.getActivity();

        binding.addActivityResultListener((int requestCode, int resultCode, Intent data) -> {
            IntentLogger.logFullContent(data);
            Bundle bundle = data.getExtras();

            for (String extraKey : bundle.keySet()) {
                if (extraKey.equals("status")) {
                    resultStatus = Integer.parseInt(bundle.get(extraKey).toString());
                }
            }

            
            return true;
        });

    }

    @Override
    public void onDetachedFromActivity() {

    }

    @Override
    public void onReattachedToActivityForConfigChanges(ActivityPluginBinding binding) {

    }

    @Override
    public void onDetachedFromActivityForConfigChanges() {

    }

    @Override
    public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
        this.result = result;

        if (call.method.equals("makePayment")) {

            double amount = call.argument("amount");
            int printCode = call.argument("printCode");

            MyPOSPayment payment = MyPOSPayment.builder().productAmount(amount).currency(Currency.EUR)
                    .printCustomerReceipt(printCode).printMerchantReceipt(printCode).build();
            MyPOSAPI.openPaymentActivity(activity, payment, 1);
            


        } else if (call.method.equals("refund")) {

            double amount = call.argument("amount");
            int printCode = call.argument("printCode");

            MyPOSRefund refund = MyPOSRefund.builder().refundAmount(amount).currency(Currency.EUR)
                    .printCustomerReceipt(printCode).printMerchantReceipt(printCode).build();

            MyPOSAPI.openRefundActivity(activity, refund, 2);
        } else {
            result.notImplemented();
        }
    }

    @Override
    public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
        channel.setMethodCallHandler(null);
    }
}

With this code snippet, I'm getting no error, but of course I never know the result of the operation.
I think, the only way to get the result is made by Result object through success method.

Unfortunately, I don't get any errors in debug mode.
Have you any tips in order to find a solution for this problem?
Let me know if you need more details about.

[developermypos]

Hello,

Sorry for the inconvenience!

We are investigating the issue.
Is the result.success(resultStatus) method a heavy operation that might block the main thread of the app causing the black screen?

Kind regards,
MyPOS

[amentone]

Hi, thanks for your reply.
This method exposes an interface for sending results back to Flutter, and it must be called on the platform thread (Android main thread). So I think that it don't block the main thread because is being used by it.

[amentone]

Resolved, there was a bug in my Flutter plugin. Thank you for your time!