如何连接和使用串口？

Question

我与UsbDeviceConnection的连接有问题。我不能使用serialPort.open吗？当我删除UsbEndpoint和UsbInterface，connection.claimInterface和bulkTransfer时，我进入我的应用程序时，如果没有崩溃应用程序，则无法打开端口

但是如果我在这里使用代码，则会得到：E / UsbManager：UsbManager.openDevice中的异常     java.lang.SecurityException：用户未授予设备UsbDevice的权限...

BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();

//            UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
//            UsbDeviceConnection connection = usbManager.openDevice(device);
//            handleIntent(getIntent());

            if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)) {
                UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                UsbDeviceConnection connection = usbManager.openDevice(device);
                UsbInterface intf = device.getInterface(0);
                UsbEndpoint endpoint = intf.getEndpoint(0);
                connection.claimInterface(intf, true);
                connection.bulkTransfer(endpoint, "test".getBytes(), "test".length(), 0);

                if(device != null) {
//                printSomething();
                    UsbSerialDevice serialPort = UsbSerialDevice.createUsbSerialDevice(device, connection);

                    boolean granted = intent.getExtras().getBoolean(UsbManager.EXTRA_PERMISSION_GRANTED);
                    if(granted) {
                        serialPort.open();
                        showCommand.setText("serial port " + serialPort.syncOpen());
                    }
                    else{
                        showCommand.setText("Can't open port" + endpoint.getType());
                    }
                }
                else{
//                    showCommand.setText("Test");
                    printSomething();
                }
            }


        }
    };