Some time back I suggested to allow apps to define multiple entry points, so an app can also act as a widget (or even watch face). This would probably solve your problem (as well as mine) to share data between those "entry points". But unfortunately this was decided to not being integrated in the future... In my opinion it would really improve the user experience at least between apps and widgets... bad luck...
We just released a service that enables secure communication between apps. Shared storage can be emulated using this. You can learn more at https://dacrosse.com
