How to detect orientation change

Question

I am using Swift and I want to be able to load a UIViewController when I rotate to landscape  can anyone point me in the right direction   I Can t find anything online and a little bit confused by the documentation

User · Answer

In Objective C  - void viewWillTransitionToSize  CGSize size withTransitionCoordinator  id lt UIViewControllerTransitionCoordinator gt  coordinator   In swift  func viewWillTransitionToSize size  CGSize  withTransitionCoordinator coordinator  UIViewControllerTransitionCoordinator    Override this method to detect the orientation change

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Swift 5  Setup class to receive notifications of device orientation change   class MyClass                 init                               super init                  subscribe to device orientation change notifications         UIDevice current beginGeneratingDeviceOrientationNotifications           NotificationCenter default addObserver self  selector   selector orientationChanged   name  UIDevice orientationDidChangeNotification  object  nil                                    Setup handler code    objc extension MyClass       func orientationChanged   notification  NSNotification            let device   notification object as  UIDevice         let deviceOrientation   device orientation          switch deviceOrientation           case  landscapeLeft      do something for landscape left         case  landscapeRight     do something for landscape right         case  portrait           do something for portrait         case  portraitUpsideDown    do something for portrait upside-down          case  faceDown           do something for face down         case  faceUp             do something for face up         case  unknown            handle unknown          unknown default         handle unknown default

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I use UIUserInterfaceSizeClass to detect a orientation changed in a UIViewController class just like that   override func willTransition to newCollection  UITraitCollection  with coordinator  UIViewControllerTransitionCoordinator         let isiPadLandscapePortrait   newCollection horizontalSizeClass     regular  amp  amp  newCollection verticalSizeClass     regular     let isiPhonePlustLandscape   newCollection horizontalSizeClass     regular  amp  amp  newCollection verticalSizeClass     compact     let isiPhonePortrait   newCollection horizontalSizeClass     compact  amp  amp  newCollection verticalSizeClass     regular     let isiPhoneLandscape   newCollection horizontalSizeClass     compact  amp  amp  newCollection verticalSizeClass     compact       if isiPhonePortrait               do something

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-  void viewDidLoad      super viewDidLoad       NSNotificationCenter defaultCenter addObserver self selector  selector OrientationDidChange   name UIDeviceOrientationDidChangeNotification object nil      - void OrientationDidChange  NSNotification  notification     UIDeviceOrientation Orientation   UIDevice currentDevice orientation      if Orientation  UIDeviceOrientationLandscapeLeft    Orientation  UIDeviceOrientationLandscapeRight        NSLog   Landscape        else if Orientation  UIDeviceOrientationPortrait        NSLog   Potrait Mode            NOTE  Just use this code to identify UIViewController is in which orientation

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Using -orientation property of UIDevice is not correct  even if it could work in most of cases  and could lead to some bugs  for instance UIDeviceOrientation consider also the orientation of the device if it is face up or down  there is no direct pair in UIInterfaceOrientation enum for those values  Furthermore  if you lock your app in some particular orientation  UIDevice will give you the device orientation without taking that into account  On the other side iOS8 has deprecated the interfaceOrientation property on UIViewController class   There are 2 options available to detect the interface orientation    Use the status bar orientation Use size classes  on iPhone if they are not overridden they could give you a way to understand the current interface orientation    What is still missing is a way to understand the direction of a    change of interface orientation  that is very important during    animations  In the session of WWDC 2014  View controller    advancement in iOS8  the speaker provides a solution to that problem    too  using the method that replaces    -will DidRotateToInterfaceOrientation    Here the proposed solution partially implemented  more info here    func viewWillTransitionToSize size  CGSize  withTransitionCoordinator coordinator  UIViewControllerTransitionCoordinator            let orientation   orientationFromTransform coordinator targetTransform            let oldOrientation   UIApplication sharedApplication   statusBarOrientation         myWillRotateToInterfaceOrientation orientation duration  duration          coordinator animateAlongsideTransition    ctx  in             self myWillAnimateRotationToInterfaceOrientation orientation              duration duration                    ctx  in                 self myDidAnimateFromInterfaceOrientation oldOrientation

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I need to detect rotation while using the camera with AVFoundation  and found that the didRotate  now deprecated   amp  willTransition methods were unreliable for my needs  Using the notification posted by David did work  but is not current for Swift 3 x  amp  above  The following makes use of a closure  which appears to be Apple s preference going forward  var didRotate   Notification  - gt  Void     notification in         switch UIDevice current orientation           case  landscapeLeft   landscapeRight              print  quot landscape quot           case  portrait   portraitUpsideDown              print  quot Portrait quot           default              print  quot other  such as face up  amp  down  quot                    To set up the notification  NotificationCenter default addObserver forName  UIDevice orientationDidChangeNotification                                         object  nil                                         queue   main                                         using  didRotate   To tear down the notification  NotificationCenter default removeObserver self                                            name  UIDevice orientationDidChangeNotification                                            object  nil   Regarding the deprecation statement  my initial comment was misleading  so I wanted to update that  As noted  the usage of  objc inference has been deprecated  which in turn was needed to use a  selector  By using a closure instead  this can be avoided and you now have a solution that should avoid a crash due to calling an invalid selector

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My approach is similar to what bpedit shows above  but with an iOS 9  focus  I wanted to change the scope of the FSCalendar when the view rotates   override func viewWillTransitionToSize size  CGSize  withTransitionCoordinator coordinator  UIViewControllerTransitionCoordinator        super viewWillTransitionToSize size  withTransitionCoordinator  coordinator       coordinator animateAlongsideTransition    context  in         if size height  lt  size width               self calendar setScope  Week  animated  true              self calendar appearance cellShape    Rectangle                   else               self calendar appearance cellShape    Circle             self calendar setScope  Month  animated  true                         completion  nil      This below worked  but I felt sheepish about it     coordinator animateAlongsideTransition    context  in         if size height  lt  size width               self calendar scope    Week             self calendar appearance cellShape    Rectangle                         context  in             if size height  gt  size width                   self calendar scope    Month                 self calendar appearance cellShape    Circle

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Full working implementation of how to detect orientation change in Swift 3 0   I chose to use this implementation because phone orientations of face up and face down were important to me  and I wanted the view to change only once I knew the orientation was in the specified position     import UIKit  class ViewController  UIViewController        override func viewDidLoad             super viewDidLoad             1         NotificationCenter default addObserver self  selector   selector deviceOrientationDidChange   name  NSNotification Name UIDeviceOrientationDidChange  object  nil              deinit             3         NotificationCenter default removeObserver self  name  NSNotification Name UIDeviceOrientationDidChange  object  nil             func deviceOrientationDidChange               2         switch UIDevice current orientation           case  faceDown              print  Face down           case  faceUp              print  Face up           case  unknown              print  Unknown           case  landscapeLeft              print  Landscape left           case  landscapeRight              print  Landscape right           case  portrait              print  Portrait           case  portraitUpsideDown              print  Portrait upside down                        The important pieces to note are    You listen to the DeviceOrientationDidChange notification stream and tie it to the function deviceOrientationDidChange You then switch on the device orientation  be sure to take notice that there is an unknown orientation at times  Like any notification  before the viewController is deinitialized  make sure to stop observing the notification stream    Hope someone finds this helpful

User · Answer

Use the new  viewWillTransitionToSize   withTransitionCoordinator

User · Answer

If you want to do something AFTER the rotation is complete  you can use the UIViewControllerTransitionCoordinator completion handler like this  public override func viewWillTransition to size  CGSize  with coordinator  UIViewControllerTransitionCoordinator        super viewWillTransition to  size  with  coordinator          Hook in to the rotation animation completion handler     coordinator animate alongsideTransition  nil        in            Updates to your UI            self tableView reloadData

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Here s how I got it working   In AppDelegate swift inside the didFinishLaunchingWithOptions  function I put   NotificationCenter default addObserver self  selector   selector AppDelegate rotated   name  UIDevice orientationDidChangeNotification  object  nil    and then inside the AppDelegate class I put the following function    func rotated         if UIDeviceOrientationIsLandscape UIDevice current orientation            print  Landscape              if UIDeviceOrientationIsPortrait UIDevice current orientation            print  Portrait             Hope this helps anyone else   Thanks

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Check if rotation had changed with  viewWillTransitionToSize size  CGSize  withTransitionCoordinator coordinator  UIViewControllerTransitionCoordinator   With the coordinator animateAlongsideTransition nil     UIViewControllerTransitionCoordinatorContext  you can check if the transition is finished   See code below   override func viewWillTransitionToSize size  CGSize  withTransitionCoordinator coordinator  UIViewControllerTransitionCoordinator         super viewWillTransitionToSize size  withTransitionCoordinator  coordinator       coordinator animateAlongsideTransition nil     UIViewControllerTransitionCoordinatorContext  in            if you want to execute code after transition finished         print  Transition finished              if size height  lt  size width              Landscape         print  Landscape         else              Portrait         print  Portrait

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I know this question is for Swift  but since it s one of the top links for a Google search and if you re looking for the same code in Objective-C      add the observer   NSNotificationCenter defaultCenter  addObserver self selector  selector rotated   name UIDeviceOrientationDidChangeNotification object nil       remove the observer   NSNotificationCenter defaultCenter  removeObserver self name UIDeviceOrientationDidChangeNotification object nil       method signature -  void rotated  NSNotification   notification          do stuff here

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Easy  this works in iOS8 and 9   Swift 2   Xcode7  just put this code inside your viewcontroller swift  It will print the screen dimensions with every orientation change  you can put your own code instead   override func didRotateFromInterfaceOrientation fromInterfaceOrientation  UIInterfaceOrientation            getScreenSize             var screenWidth CGFloat 0     var screenHeight CGFloat 0     func getScreenSize            screenWidth UIScreen mainScreen   bounds width         screenHeight UIScreen mainScreen   bounds height         print  SCREEN RESOLUTION    screenWidth description   x   screenHeight description

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For Swift 3  override func viewWillTransition to size  CGSize  with coordinator  UIViewControllerTransitionCoordinator        if UIDevice current orientation isLandscape             Landscape           else if UIDevice current orientation isFlat             isFlat           else             Portrait

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Since iOS 8 this is the correct way to do it   override func viewWillTransition to size  CGSize  with coordinator  UIViewControllerTransitionCoordinator        super viewWillTransition to  size  with  coordinator       coordinator animate alongsideTransition    context in            This is called during the animation        completion    context in            This is called after the rotation is finished  Equal to deprecated  didRotate

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Swift 3   UIDeviceOrientationDidChange Notification Observed Too Often  The following code prints  deviceDidRotate  every time your device changes orientation in 3D space - regardless of a change from portrait to landscape orientation  For example  if you hold your phone in portrait orientation and tilt it forward and backward - deviceDidRotate   is called repeatedly   override func viewDidLoad         super viewDidLoad       NotificationCenter default addObserver          self           selector    selector deviceDidRotate            name   UIDeviceOrientationDidChange           object  nil          func deviceDidRotate         print  deviceDidRotate       To work around this you could hold the previous device orientation and check for a change in deviceDidRotate     var previousDeviceOrientation  UIDeviceOrientation   UIDevice current orientation  override func viewDidLoad         super viewDidLoad       NotificationCenter default addObserver          self           selector    selector deviceDidRotate            name   UIDeviceOrientationDidChange           object  nil          func deviceDidRotate         if UIDevice current orientation    previousDeviceOrientation   return       previousDeviceOrientation   UIDevice current orientation     print  deviceDidRotate       Or you can use a different notification that only gets called when the device changes from landscape to portrait  In this case you d want to use the UIApplicationDidChangeStatusBarOrientation notification   override func viewDidLoad         super viewDidLoad       NotificationCenter default addObserver          self           selector    selector deviceDidRotate            name   UIApplicationDidChangeStatusBarOrientation           object  nil          func deviceDidRotate         print  deviceDidRotate

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Here is an easy way to detect the device orientation   Swift 3   override func willRotate to toInterfaceOrientation  UIInterfaceOrientation  duration  TimeInterval                handleViewRotaion orientation  toInterfaceOrientation                   MARK  - Rotation controls     func handleViewRotaion orientation UIInterfaceOrientation  - gt  Void           switch orientation           case  portrait               print  portrait view               break         case  portraitUpsideDown               print  portraitUpsideDown view               break         case  landscapeLeft               print  landscapeLeft view               break         case  landscapeRight               print  landscapeRight view               break         case  unknown               break

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override func didRotate from fromInterfaceOrientation  UIInterfaceOrientation          swift 3     getScreenSize       func getScreenSize       let screenWidth   UIScreen main bounds width    let  screenHeight   UIScreen main bounds height     print  SCREEN RESOLUTION    screenWidth description  x   screenHeight description

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According to the Apple docs   This method is called when the view controller s view s size is changed by its parent  i e  for the root view controller when its window rotates or is resized    override func viewWillTransition to size  CGSize  with coordinator  UIViewControllerTransitionCoordinator        super viewWillTransition to  size  with  coordinator           if UIDevice current orientation isLandscape           print  quot Landscape quot             if UIDevice current orientation isFlat           print  quot Flat quot         else           print  quot Portrait quot

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override func viewDidLoad         NotificationCenter default addObserver self  selector   selector MyController rotated   name  UIDevice orientationDidChangeNotification  object  nil            objc private func rotated         if UIDevice current orientation isLandscape          else if UIDevice current orientation isPortrait                 or you can check orientation separately UIDevice current orientation       portrait  portraitUpsideDown  landscapeLeft  landscapeRight

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With iOS 13 1 2  orientation always return 0 until device is rotated  I need to call UIDevice current beginGeneratingDeviceOrientationNotifications   before any rotation event occurs to get actual rotation

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I like checking the orientation notification because you can add this feature in any class  no needs to be a view or a view controller  Even in your app delegate   SWIFT 5         ask the system to start notifying when interface change     UIDevice current beginGeneratingDeviceOrientationNotifications         add the observer     NotificationCenter default addObserver          self          selector   selector orientationChanged notification             name  UIDevice orientationDidChangeNotification          object  nil    than caching the notification       objc func orientationChanged notification   NSNotification              your code there

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Swift 4   override func viewWillAppear   animated  Bool        NotificationCenter default addObserver self  selector   selector deviceRotated   name  UIDevice orientationDidChangeNotification  object  nil     override func viewWillDisappear   animated  Bool        NotificationCenter default removeObserver self  name  UIDevice orientationDidChangeNotification  object  nil      objc func deviceRotated        if UIDevice current orientation isLandscape             Code here       else             Code here           A lot of answers dont help when needing to detect across various view controllers  This one does the trick

[ios] How to detect orientation change?

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