How to read changes to shared values caused by "sub" activity from main activity?

When the main activity starts the "sub" activity and the "s开发者_开发知识库ub" activity makes changes to the shared values and is then destroyed (e.g. using the back option on a phone), is there a direct way of reading the changes at this stage?

On searching this matter I could only find references to using intent.putExtras and intent.getExtras plus using a bundle object. Are these the only way of handling the information ?

I tried to read the preferences from shared preferences straight after the activity was called thinking that when it finished this would be the next part it would do.

---

Reading the preferences in you onResume() for your main activity is the statergy I use. It gets them in on startup or after the preferenceActivity has changes, or after any other activity that may of changed them.