printing - Send plain text to an USB Printer in Android -


after reading question: android usb permissions dialog never appears , doing tests, have following problem :

i need print usb printer (only plain text), establish connection, dialog appears, don't after this. can me must in openport(adevice)?

this try:

................  if (musbmanager.haspermission(mdevice)){ final usbdeviceconnection mconnection = musbmanager.opendevice(mdevice); intf = mdevice.getinterface(0); (int = 0; < intf.getendpointcount(); i++) {    usbendpoint ep = intf.getendpoint(i);    if (ep.gettype() == usbconstants.usb_endpoint_xfer_bulk) {            if (ep.getdirection() == usbconstants.usb_dir_out) {            mendpointbulkout = ep;                usbdeviceconnection connection = musbmanager.opendevice(mdevice);            if(connection!=null)            {              log.e(tag," conectado");            }            connection.claiminterface(intf, forceclaim);            //integer res = connection.bulktransfer(mendpointbulkout, bytes, bytes.length, timeout);            new thread(new runnable()             {             @override             public void run()             {                 // todo auto-generated method stub                 log.i(tag, "in run thread");                 int b = mconnection.bulktransfer(mendpointbulkout, bytes, bytes.length, 100000);                 log.i(tag, "b-->" + b);                 }                 }).start();                  connection.releaseinterface(intf);            break;        }  } } } else  musbmanager.requestpermission(mdevice, mpermissionintent); break;`

.......

mconnection.bulktransfer alwais return -1

your mconnection null thread , new thread doesn't have access usbdeviceconnection. rebuild application, follow usb host more or @ least try put mconnection in singleton.

also can try connect proxy application: net2usb


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