How to use AVCaptureSession with Slide Over and Split View in iOS 9?

In case you haven't found out yet. After some more investigation I can now answer your first question:

If AVCaptureSession is immediately paused when Slide Over and Split View are used, is it a good idea to monitor AVCaptureSessionDidStopRunningNotification, and present a message "Camera Paused" to the user, so that he clearly knows that the app isn't performing scanning?

The notification you actually want to observe is this one: AVCaptureSessionWasInterruptedNotification

And you want to check for the newly introduced in iOS9 reason: AVCaptureSessionInterruptionReason.VideoDeviceNotAvailableWithMultipleForegroundApps

override func viewWillAppear(animated: Bool){    super.viewWillAppear(animated)    self.addObserverForAVCaptureSessionWasInterrupted()}func addObserverForAVCaptureSessionWasInterrupted(){    let mainQueue = NSOperationQueue.mainQueue()    NSNotificationCenter.defaultCenter().addObserverForName(AVCaptureSessionWasInterruptedNotification, object: nil, queue: mainQueue)        { (notification: NSNotification) -> Void in            guard let userInfo = notification.userInfo else            {                return            }            // Check if the current system is iOS9+ because AVCaptureSessionInterruptionReasonKey is iOS9+ (relates to Split View / Slide Over)            if #available(iOS 9.0, *)            {                if let interruptionReason = userInfo[AVCaptureSessionInterruptionReasonKey] where Int(interruptionReason as! NSNumber) == AVCaptureSessionInterruptionReason.VideoDeviceNotAvailableWithMultipleForegroundApps.rawValue                {                    // Warn the user they need to get back to Full Screen Mode                }            }            else            {                // Fallback on earlier versions. From iOS8 and below Split View and Slide Over don't exist, no need to handle anything then.            }        }}override func viewWillDisappear(animated: Bool){    super.viewWillDisappear(true)    NSNotificationCenter.defaultCenter().removeObserver(self)}

You can also know when the interruption was ended by observing:AVCaptureSessionInterruptionEndedNotification

Answer based on these two links:

http://asciiwwdc.com/2015/sessions/211https://developer.apple.com/library/ios/samplecode/AVCam/Introduction/Intro.html