A class representing USB request packet. This can be used for both reading and writing data to or from a UsbDeviceConnection. UsbRequests can be used to transfer data on bulk and interrupt endpoints. Requests on bulk endpoints can be sent synchronously via bulkTransfer(UsbEndpoint, byte[], int, int) or asynchronously via queue(ByteBuffer, int) and requestWait(). Requests on interrupt endpoints are only send and received asynchronously.

google有提到, HID的中斷傳輸可以用queue完成.可以不用bulkTransfer及controlTransfer

寫code時,最好拿到USB protocol分析儀看一下android手機送出的封包. google上查到的範例code,很多作者沒寫好.可以用,但是有bug .