Working with USB

hello, everybodyI'm trying to find out what devices are connected to usb MK802II (have usb host) Android 4.01Connect the mouse and mobilrek

Sub Process_Globals
Dim manusb() As UsbDevice
Dim manan As UsbManager
End Sub

Sub Activity_Create(FirstTime As Boolean)
Activity.LoadLayout("34")
manan.Initialize
manusb=manan.GetDevices
Dim nn As String
nn=manusb.Length
Msgbox("Total devices - " & nn, "")
End Sub


Response 0!!
Head broke, help advice
What is wrong?