On a Sunmi K2 Terminal how can I print (on the build-in printer) something using WinDev Mobile?

Question

I'm using a Sunmi K2 POS Checkout Terminal running with Android 7.1.2

I'm developing a POS software with WinDev for Mobile 26, I'm already displaying some windows, now the question is, how can I print on the build-in pos printer??

There is a print-test app on the kiosk installed, this works fine.

In the settings there is a printer settings too, but this says "no device installed"...

In the documentation there is a "AIDL interface" mentioned...

And more, there is a API sample written:

Bound Service

Intent intent = new Intent();
intent.setPackage("com.sunmi.extprinterservice");
intent.setAction("com.sunmi.extprinterservice.PrinterService");
bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);

It is necessary to establish a new ServiceConnection service to bind the callback

ServiceConnection serviceConnection = new ServiceConnection() {
@Override public void onServiceConnected(ComponentName name, IBinder service) {
ExtPrinterService ext = ExtPrinterService.Stub.asInterface(service);
}
@Override public void onServiceDisconnected(ComponentName name) { }
};

Use ext object to realize one’s own printing task

ext.printText(“123456\n”);

Unbind the service after the completion of the usage

unbindService(serviceConnection);

Question is, how can I use this Java code in WinDev Mobile??

EDIT:

I managed to print to the printer, but there is a small bug, so sometime it doesn't start immediatly, so therefore is the loop...

import android.content.ComponentName;
import android.content.Context;
import static android.content.Context.BIND_AUTO_CREATE;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.IBinder;
import android.widget.Toast;
import com.sunmi.extprinterservice.ExtPrinterService;

public static void PrintToSunmiPrinter(byte[] cmd) {
    
    getCurrentActivity();
    Context context = getApplicationContext();
    ExtPrinterService ext;
    
    ServiceConnection serviceConnection = new ServiceConnection() {
        @Override public void onServiceConnected(ComponentName className, IBinder service) {
            // This is called when the connection with the service has been
            // established, giving us the service object we can use to
            // interact with the service.  Because we have bound to a explicit
            // service that we know is running in our own process, we can
            // cast its IBinder to a concrete class and directly access it.
            try {

                ExtPrinterService ext = ExtPrinterService.Stub.asInterface(service);
                int ret_code;
                int zz=0;
                
                ret_code=ext.printerInit();
                while(ret_code==-1){
                    zz++;
                    if (zz>100) { Toast.makeText(context, "ERROR! / "+ret_code, Toast.LENGTH_SHORT).show(); break; }
                    ret_code=ext.printerInit();
                }
                
                ext.sendRawData(cmd);
                ext.cutPaper(1, 0);
                ext.flush();
            }  catch(Exception ex){
                Toast.makeText(getApplicationContext(), "ERROR! "+ex.getMessage(), Toast.LENGTH_SHORT).show();
            }
        }
        
        @Override public void onServiceDisconnected(ComponentName className) {
            // This is called when the connection with the service has been
            // unexpectedly disconnected -- that is, its process crashed.
            // Because it is running in our same process, we should never
            // see this happen.
        }
    };
    
    Intent intent = new Intent();
    intent.setPackage("com.sunmi.extprinterservice");
    intent.setAction("com.sunmi.extprinterservice.PrinterService");
    context.bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);
}