安卓（配件模式）和视窗电脑（主机）之间的USB通信

我尝试在我的笔记本电脑（win7）和我的Android手机（Android 4.2）之间建立USB连接。笔记本电脑应充当主机为Android手机供电。目标是笔记本电脑和手机可以发送和接收xml字符串

我试图按照解释配件模式的Android页面（http://developer.android.com/guide/topics/connectivity/usb/accessory.html）。

• 1：我必须像这里一样定义一个附件过滤器：

  <?xml version="1.0" encoding="utf-8"?>
  <resources>
  <usb-accessory model="DemoKit" manufacturer="Google" version="1.0"/>
  </resources>
  

  因为我不希望特殊硬件被识别。我希望所有类型的Windows计算机都能被识别（例如，我将手机插入另一台PC）。

• 2：我现在在窗户方面什么也没做。我只是按照Android页面，插入USB电缆并观看日志。应用启动器请求权限，但附件为 null。任何提示为什么它是空的？法典：

  public class MainActivity extends Activity {
  private static final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";
  private static final String TAG = "USB_PERMISSION";
  UsbAccessory accessory;
  
  protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  
  UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
  
  PendingIntent mPermissionIntent = PendingIntent.getBroadcast(this, 0,
          new Intent(ACTION_USB_PERMISSION), 0);
  IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
  registerReceiver(mUsbReceiver, filter);
  accessory = (UsbAccessory) getIntent().getParcelableExtra(
          UsbManager.EXTRA_ACCESSORY);
  manager.requestPermission(accessory, mPermissionIntent);
   }
  
  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) {
              if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                  String manufacturer;
                  Log.d(TAG, "permission accepted for accessory " + accessory);
                  if (accessory != null) {
                      manufacturer = accessory.getManufacturer();
                      Log.d(TAG, "Manufacturer: " + manufacturer);                        }
              } else {
                  Log.d(TAG, "permission denied for accessory "+ accessory);
              }
          }
      }
  }
  };
  }
  

• 3： 是否有任何库/项目可用于识别Windows端的USB连接？

• 4： 还有什么我应该考虑的吗？错的事情？
• 5：感谢您的帮助:)