Activity gets killed but saved bundle is not received in onCreate

I have an application开发者_高级运维 that works without fragments. I modified an activity to use fragments. The problem is that now when the activity goes in background and then in foreground again the onCreate is called: it looks like the activity gets killed to save memory or for another reason.

I tried to save a bundle in onSaveInstanceState but when the activity is opened again I receive a null bundle in the onCreate and no call to onRestoreInstanceState (I checked that I receive a call to onSaveInstanceState when going in background).

Any clue?

thanks

I recently updated my first application to use Fragments. I create the bundle in onSaveInstanceState and then I retrieve the bundle in onActivityCreated. Both methods are in the Fragment derived class! Maybe you're creating the bundle in the Fragment and then trying to retrieve it in the Activity?