Hi All,
I recently bought a Nexus 7 for USB development. I would like to use the
USB Host functionality provided by the new Android OS. I was following the
USB Host Tutorial at the link:
http://developer.android.com/guide/topics/connectivity/usb/host.html.
My program is very simple, and here are the relevant parts of the code:
* private UsbManager manager;
*
* *
* public void onCreate(Bundle savedInstanceState) {*
* super.onCreate(savedInstanceState);*
* setContentView(R.layout.activity_main);*
* *
* Log.i(TAG, "in onCreate()");*
* manager = (UsbManager) getSystemService(Context.USB_SERVICE);*
* if(manager==null) {*
* Log.i(TAG, "USB Manager is NULL");*
* }*
* else {*
* Log.i(TAG, "USB Manager = " + manager);*
* }*
* }*
* *
* public void enumerateUSBDevices() {*
* HashMap<String, UsbDevice> deviceList = manager.getDeviceList();*
* Collection<UsbDevice> deviceCollection = deviceList.values();*
* Iterator<UsbDevice> deviceIterator = deviceCollection.iterator();*
* Log.i(TAG, "Number of connected USB Devices = " +
deviceCollection.size());*
* while(deviceIterator.hasNext()){*
* UsbDevice device = deviceIterator.next();*
* Log.i(TAG, device.getDeviceName());*
* }*
* }*
When the enumerateUSBDevices function is called, it reports that the number
of connected USB Devices = 0. I am using a USB OTG cable, and I know that
the Nexus 7 is powering the connected USB Device because I plugged in a USB
Mouse, and it works properly. I also plugged in another Android phone, and
the Nexus 7 was confirmed to be powering the device. However, in both of
these instances, the Android program says that there are no USB devices
connected. I am unsure what is going wrong in my code. In my Android
manifest, I have the following line:
*<uses-feature android:name="android.hardware.usb.host" />*
My manifest does not have any intent filters associated with any USB
devices. My understanding based on reading the tutorials is that the
intent filters need to be in the Manifest only if you want the APP to be
notified when the USB device is connected after the App is running?
Can anybody shed light into what I may be doing wrong? Do I need to root
my device?
Thanks,
Kiran
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