What type of data? Point / polygon / line?
You can add shapefile to the webmap in ArcGIS.com and open that webmap with ArcGIS Runtime SDK for iOS and you'll be able to see shapefile data on your device. However, it's just for viewing purpose, you won't be able to edit them.
Regards,
Nimesh
Could you please elaborate about your ideas behind AGSVectorServiceLayer and offline shape?
Regards,
Nimesh