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DantSu / ESCPOS-ThermalPrinter-Android

Useful library to help Android developpers to print with (Bluetooth, TCP, USB) ESC/POS thermal printer.
MIT License
1.22k stars 368 forks source link

Issue with usb connection #498

Open dashwood01 opened 8 months ago

dashwood01 commented 8 months ago

Hello, First of all, thank you for this amazing library., I can't print through USB. It connects but doesn't write anything to the output stream. I need to mention that I connected through another method and managed to print, but unfortunately, your library doesn't provide me with this capability.

dashwood01 commented 8 months ago

I made a change in your code and the issue was resolved.

 public UsbOutputStream(UsbManager usbManager, UsbDevice usbDevice) throws IOException {
        this.usbInterface = usbDevice.getInterface(0);
        for (int i = 0; i < this.usbInterface.getEndpointCount(); ++i) {
            UsbEndpoint ep = this.usbInterface.getEndpoint(i);
            if (ep.getType() == 2) {
                if (ep.getDirection() == 0) {
                    this.usbEndpoint = ep;
                } else if (ep.getDirection() == 128) {
                    this.usbEndpoint = ep;
                }
            }
        }
        if (this.usbInterface == null) {
            throw new IOException("Unable to find USB interface.");
        }
        if (this.usbEndpoint == null) {
            throw new IOException("Unable to find USB endpoint.");
        }

        this.usbConnection = usbManager.openDevice(usbDevice);
        if (this.usbConnection == null) {
            throw new IOException("Unable to open USB connection.");
        }
    }

This change should be made within the UsbOutputStream class.

zachwdev commented 8 months ago

I also have an issue that is possibly related, I get the warning: java.io.IOException: Unable to find USB interface. Then I get the error: Caused by: com.dantsu.escposprinter.exceptions.EscPosConnectionException: Unable to connect to USB device.