We have a iPhone application which is required to be ported to Android Platform.
The app does following things
a) Login and activate the app via a drupal json services
b) Store the Expense and Travel Expense in CoreData in iphone, Local Storage in Android Terms
c) Pull out list of documents from Amazon S3 storage.
d) Attach a photo with an expense and save for future upload.
e) Upload all expense and travel expense to drupal json services
f) Upload the images to Amazon S3 servers
g) Receive notification from the Apple Push Server
h) It works even in offline mode storing data and publishing when in network.