How can a user respond or react to the state transitions on the app?

A user can state changes in the most apt way in order to respond to the state transitions. Calling the corresponding methods or functions on the app’s delegate object is one way of doing this.

For instance:

• The method applicationDidBecomeActive( ) can be employed to arrange the app to run as the fore app.
• The method applicationDidEnterBackground( ) can be employed for the execution of some code during the background runtime of the app and the exercise may be put on hold at any time.
• The method applicationWillEnterForeground( ) can be employed when the app is moving into the foreground and shifting out of background and some code needs to be executed.
• The method applicationWillTerminate( ) is called to action when the app is nearing termination.