Changing Android Shared Preference Value from String to Int

Question

I'm updating my Android app. The app retrieves data from my server and among that data is a user id. The user id is a number (Integer) but it arrives from the server as a string eg "1234". In the old version I then saved this user id as a string in my shared prefernces but now that I'm looking back at it I don't like this and want to save it as an Integer as it should be.

So far pretty simple. I just use putInt / getInt rather than putString / getString. The problem is that all the people currently using the app will have the value saved in their shared preferences as a string and then when they update the app the new version of the app will start to try to use getInt to get the value which the old version saved as a string.

What's the best way to avoid any errors because of this and ensure a smoothe transition between the two app versions?

Thanks.

Answer 1

Something like that in your onCreate:

try{
   prefs.getInt("key", 0);
}catch (ClassCastException e){
   Integer uid = Integer.parseInt(prefs.getString("key", null);
   if(uid != null)
      prefs.edit().putInt("key", uid).commit();
}

Answer 2

This is as simple as

int userid = Integer.parseInt( preferences.getString("userid", ""));