Is there any way to detect USB state?

[Kode.Cooper]

Qt does not offer any way to do that. You'll have to rely on other libraries to achieve what you want (e.g libusb).

Thanks fullmetalcoder, but I found some Extended interface of QT,
such as QUsbStorageGadget, QUsbManager etc. for Embeded Linux,
Could we use these modules for our purpose?