Tells the delegate that the app has become active.
- iOS 2.0+
- tvOS 9.0+
Your singleton app object.
This method is called to let your app know that it moved from the inactive to active state. This can occur because your app was launched by the user or the system. Apps can also return to the active state if the user chooses to ignore an interruption (such as an incoming phone call or SMS message) that sent the app temporarily to the inactive state.
You should use this method to restart any tasks that were paused (or not yet started) while the app was inactive. For example, you could use it to restart timers or throttle up OpenGL ES frame rates. If your app was previously in the background, you could also use it to refresh your app’s user interface.
After calling this method, the app also posts a
UIApplication notification to give interested objects a chance to respond to the transition.