gistfile1.java

mStorageManager = (StorageManager) getSystemService(Service.STORAGE_SERVICE);
        	
mStorageManager.mountObb("/sdcard/obbtest.obb", "android", new OnObbStateChangeListener() {

    @Override
    public void onObbStateChange(String path, int state) {
        Log.d("OBBTEST", ""+path+" mount:"+state);
        if(state == OnObbStateChangeListener.MOUNTED) {
            String mountedPath = mStorageManager.getMountedObbPath("/sdcard/obbtest.obb");
						
	    if(mStorageManager.isObbMounted("/sdcard/obbtest.obb")) {
		Log.d("OBBTEST", "mounted");
	    } else {
	        Log.d("OBBTEST", "not mounted");
		File mFile = new File(mountedPath);
		String[] fList = mFile.list();
						
		for(String f:fList) {
		     Log.d("OBBTEST", f);
		}
	    }
    }
 });