Warning Android user that app update could lead to losing data from old app version?

Question

I'm writing a game for Android. When the user completes a level, they can restart from the next level if they lose (ie I need to store an integer to remember which level they got to). If the app is interrupted during play, I save the world state to disk (this is complex state storing a map and game entities).

I'd like to keep my options open in the future for changing my game code and the way the world state is saved/stored. However, I must consider the scenario when a user has an old version of the world state on their phone because they were in the middle of a game, they upgrade the app and now the app cannot load the world state.

Having to write code to migrate the old version of the data to the new version of the data would be a pain if there's some way I can avoid this. It would be nice if I could somehow ask the user to finish their current game in progress before updating. Can this be done? Are there any other options?

I don't intend to do this often. I'd like to iteratively develop my game while getting some early feedback, but this is difficult if I must fix how the world state is saved and restored now.

I hope this doesn't seem a silly question, but on a PC or a console it's perfectly OK to have games that you cannot save during a game or you can only save between levels. I'm just finding Android a bit of a pain here as you must have a save game strategy for all games.

Answer 1

You cannot prevent a user from upgrading an app, and you cannot execute any code until your app is installed (or upgraded).

Quite frankly, losing data due to an upgrade is unacceptable. If you use an SQLiteOpenHelper, you automatically get nice hooks that help you with the upgrade process.

I understand that you have a pretty complex savegame setup, but try to keep it as flexible as possible to allow for easy upgrades. There are lots of techniques that help you with that.

And Android and PCs are just completely different - on a PC, you sit down and play for hours. On Android, you play real quick and then do something else. Or, you play and get a phone call and are forced to switch away from your game.