How can I be notified when the iOS Control Center is being opened?
UIApplicationWillResignActiveNotification isn't good enough since this notification is sent also when the Notifications Center is opened, alert view appeared and other possible scenarios.
I was sure this is not possible, but QuizUp app is notified when the user open the Control Center while the user is on middle of a gameplay to prevent cheating the game.
Thanks
Hey there I did a lot of trial and error investigation and came up with a solution that turns out being very reliable. It works in all orientations and both in fullscreen (no statusbar) and in regular mode. AAWindow is a subclass of UIWindow and you can find it on GitHub.
The way I accomplished this is by overriding sendEvent in UIWindow, separating out TouchEvents from the other events and checking whether touches occur in the bottom 10 percent of the screen (which is the part that can open Control Center). If there are touches and applicationWillResignActive is called within a timespan of .5 seconds (with statusbar) or 3 seconds (without statusbar) you can be very sure that this is because of Control Center being opened. Then a NSNotification is being fired and you can react to that anywhere in the application.
I tested a UIPanGestureRecognizer approach (with and without the status bar visible—changes if the little pull tab comes up instead of control center) along with watching for the applicationWillResignActive notification, and I couldn't reliably know if control center was opened. If the pan was slow enough the gesture recognizer would trigger first, but it's definitely easy to swipe up fast enough to trigger control center and bypass the gesture recognizer firing at all.
Attempting to check if the app goes from applicationWillResignActive and then to applicationDidBecomeActive would be a pretty reliable way to know if the app entered and exited one of a couple states (control center, notification center, answering a phone call, etc), but telling the difference between say notification and control center is impossible this way.
TL;DR: I don't think there is a reliable or accurate way to tell if control center was opened, but QuizUp may be doing something interesting to fake it, and I am open to being wrong!
When Control centre is opened the cycle isn't completed. Means only the method
applicationDidResignActivity will be called but applicationDidEnterBackground won't be called. When app is minimized both methods will be called. Here you can differentiate.
