android - How to handle application upgrades from free to paid version while preserving any data

Question

Here is the context. I want to have a free version and a premium version of the same application. When people buy the application, I want them to be able to "upgrade" without losing their data, i.e. the premium version should install over the free version. I want to use the same code base and just switch a setting to build the premium version. Andoid Market does not let me convert a free app to a paid app, so the trivial option is not available.

I am curious if someone has tried this successfully. How does Android Market identify an application - will it think that the premium version is a different app and just install it in parallel?

Answer 1

My idea is the following:

• Paid version's android:versionCode should be free's android:versionCode +1
• Both should have the same package.

When paid version is installed, it will replace the free one. Actually it will update it, since it has a higher android:versionCode.

As both have the same package, they will be placed in the same folder ( /data/data/your.package) so the paid app will be able to access the free app db.