How can I determine the length of received bytes of UsbRequest.queue(..) method?

Question

I have troubles with UsbRequest class in Android 3.1.

This is my code:

ByteBuffer buffer = ByteBuffer.allocate(4096);
buffer.order(ByteOrder.LITTLE_ENDIAN);
UsbRequest request = new UsbRequest();
request.initialize(mConnection, mEndpointIn);
request.queue(buffer, 4096);

if (mConnection.requestWait() == request) {
   byte[] data = buffer.array();
}

The size of array data is 4096, but the length of really received bytes is much more smaller.

How can i determine the size of really received bytes?

Thanks.

Answer 1

This was a bug in Android. On afflicted versions, there's no workaround, because the implementation simply doesn't pass the length up.

It was fixed in JB-MR1 (API level 17 onwards).