Question

There are two apps installed on iPhone (myApp and competitorApp).competitorApp is saving user settings with using NSUserDefaults. I know all keys (value forKey) which using competitorApp. Is it possible to get values in myApp from competitorApp?

Answer 1

In the iOS App Programming Guide, in the Security section you can read:

For security reasons, iOS places each app (including its preferences
and data) in a sandbox at install time. A sandbox is a set of
fine-grained controls that limit the app’s access to files,
preferences, network resources, hardware, and so on. As part of the
sandboxing process, the system installs each app in its own sandbox
directory, which acts as the home for the app and its data.

That means that if you’re not interested in jailbreaking, what you want to do is not possible.