No doubt the most frequent approach we get for the mobile ArcGIS apps we develop are offline or disconnected workflows. Clients want both to be able to visualize basemaps and their layers when out of wi-fi range, and offline editing; new feature additions, deletions and attribute edits.
ArcGIS 10.1 gives us tile packages (.tpk) so we can store tile pyramids locally on the device. Mansour has a nice example showing how to access basemap tiles using a tpk in offline mode on his blog.
The real challenge is offline editing. ESRI introduced Feature Server with Feature layers in ArcGIS 10, which work nicely in online mode. In April they released an Online-Offline Editing Sample using their iOS api. They include in their notes supporting the sample:
“For the sake of simplicity, the sample ….only allows you to add new features when the application is offline, not modify or delete existing features.”
Now there is the real challenge, what they have left out of the sample.