FileObserver not working in XOOM android 3.1

In my app I have a FileObserver on /mnt/sdcard/dcim/camera folder so that whenever an image i开发者_JS百科s taken from a camera my app is notified. It works as expected on phones having Android 2.1/2.2/2.3. I am trying to make it work on a Motorola Xoom with Android 3.1/3.2 but it doesnt work. I checked this folder exists and whenever an image is taken using the camera app that a file with that image is created in /mnt/sdcard/dcim/camera but somehow OnEvent() method of FileObserver is not called. Anyone else faced the same issue?