Question

我正在尝试通过USB OTG电缆连接两台带有API 14+的Android设备，

但是当我访问以下两个null时，我得到API个值

mUsbManager.getDeviceList();

mUsbManager.getAccessoryList();

如果您有任何想法，请帮助我分享您的想法或示例应用的任何示例。

Answer 1

您是否通过意图请求许可甚至看到附加的内容？

您是在定义自己的自定义类型和通信层，还是尝试通过adb ....这里有更多信息可能会很好。但就目前而言，您需要知道您是否能够看到该设备。

此问题在AOA v2页面中有所定义：CSS selector

从https://source.android.com/devices/accessories/aoa2.html

复制的文字

private void checkInfo() {
        manager = (UsbManager) getSystemService(Context.USB_SERVICE);
        /*
         * this block required if you need to communicate to USB devices it's
         * take permission to device
         * if you want than you can set this to which device you want to communicate   
         */
        // ------------------------------------------------------------------
        mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(
                ACTION_USB_PERMISSION), 0);
        IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
        registerReceiver(mUsbReceiver, filter);
        // -------------------------------------------------------------------
        HashMap<string , UsbDevice> deviceList = manager.getDeviceList();
        Iterator<usbdevice> deviceIterator = deviceList.values().iterator();
        String i = "";
        while (deviceIterator.hasNext()) {
            device = deviceIterator.next();
            manager.requestPermission(device, mPermissionIntent);
            i += "\n" + "DeviceID: " + device.getDeviceId() + "\n"
                    + "DeviceName: " + device.getDeviceName() + "\n"
                    + "DeviceClass: " + device.getDeviceClass() + " - "
                    + "DeviceSubClass: " + device.getDeviceSubclass() + "\n"
                    + "VendorID: " + device.getVendorId() + "\n"
                    + "ProductID: " + device.getProductId() + "\n";
        }

        textInfo.setText(i);
    }

    private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {

        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (ACTION_USB_PERMISSION.equals(action)) {
                synchronized (this) {
                    UsbDevice device = (UsbDevice) intent
                            .getParcelableExtra(UsbManager.EXTRA_DEVICE);
                    if (intent.getBooleanExtra(
                            UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                        if (device != null) {
                            // call method to set up device communication
                        }
                    } else {
                        Log.d("ERROR", "permission denied for device " + device);
                    }
                }
            }
        }
};

通过USB线使用AOA协议建立两个Android设备之间的通信

1 个答案: