public class DeviceAttachReceiver extends BroadcastReceiver {
    public static final String ACTION_USB_PERMISSION = "redacted.permission";
    @Override
    public void onReceive(Context context, Intent intent) {
        if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(intent.getAction())) {
            //Device was attached, ask for permission
            UsbManager usbManager = (UsbManager)context.getSystemService(Context.USB_SERVICE);
            UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
            usbManager.requestPermission(device, PendingIntent.getBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), 0));
        } else if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(intent.getAction())) {
            //Disconnected
            UsbMonitorConnection.disconnect();
        }
    }
}

public class UsbPermissionReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        if (MonitorAttachReceiver.ACTION_USB_PERMISSION.equals(intent.getAction())) {
            UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
            boolean granted = intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false);
            if (granted) {
                //Permission granted, connect the device
                UsbMonitorConnection.connect(context, device);
            }
        }
    }
}