Execute action when back bar button of UINavigationController is pressed

Question

I need to execute an action  emptying an array   when the back button of a UINavigationController is pressed  while the button still causes the previous ViewController on the stack to appear  How could I accomplish this using swift

User · Answer

Swift 5    Xcode 11 5  In my case I wanted to make an animation  and when it finished  go back  A way to overwrite the default action of the back button and call your custom action is this         override func viewDidAppear   animated  Bool            super viewDidAppear animated          setBtnBack              private func setBtnBack             for vw in navigationController  navigationBar subviews       where    vw classForCoder        UINavigationBarContentView                print    vw classForCoder                for subVw in vw subviews where    subVw classForCoder        UIButtonBarButton                    let ctrl   subVw as  UIControl                 ctrl removeTarget ctrl allTargets first  action  nil  for   allEvents                  ctrl addTarget self  action   selector backBarBtnAction   for   touchUpInside                                       objc func backBarBtnAction             doSomethingBeforeBack    weak self  isEndedOk  in             if isEndedOk                   self  navigationController  popViewController animated  true                                      private func doSomethingBeforeBack completion   escaping    isEndedOk Bool - gt Void             UIView animate withDuration  0 25  animations     weak self  in             self  vwTxt alpha   0               isEnded  in             completion isEnded                      Or you can use this method one time to explore the NavigationBar view hierarchy  and get the indexes to access to the  UIButtonBarButton view  cast to UIControl  remove the target-action  and add your custom targets-actions       private func debug printSubviews arrSubviews  UIView    level Int            for  i subVw  in  arrSubviews        enumerated                 var str                  for   in 0   level                   str      t                            str    String format    2d     i     subVw classForCoder                print str              debug printSubviews arrSubviews  subVw subviews  level  level   1                          Set directly the indexs     private func setBtnBack method2                Remove or comment the print lines         debug printSubviews arrSubviews  navigationController  navigationBar subviews  level  0             let ctrl   navigationController  navigationBar subviews 1  subviews 0  as  UIControl         print  ctrl allTargets    ctrl allTargets            ctrl removeTarget ctrl allTargets first  action  nil  for   allEvents          print  ctrl allTargets    ctrl allTargets            ctrl addTarget self  action   selector backBarBtnAction   for   touchUpInside          print  ctrl allTargets    ctrl allTargets

User · Answer

When back button is pressed  ignore interactive pop with screen edge gesture  override func viewWillDisappear   animated  Bool        super viewWillDisappear animated           if isMovingFromParent  transitionCoordinator  isInteractive    false            code here

User · Answer

This is my solution  extension UINavigationController  UINavigationBarDelegate       public func navigationBar   navigationBar  UINavigationBar  shouldPop item  UINavigationItem  - gt  Bool           if let shouldBlock   self topViewController  shouldPopFromNavigation                 return shouldBlock                   return true          extension UIViewController        objc func shouldPopFromNavigation   - gt  Bool           return true           In your view controller  you can handle like this     objc override func shouldPopFromNavigation   - gt  Bool              Your dialog  example UIAlertViewController or whatever you want         return false

User · Answer

Before leave current controller I need to show alert  So I did it this way    Add extention to UINavigationController with UINavigationBarDelegate Add selector to your controller navigationShouldPopOnBack completion     It s worked   extension UINavigationController  UINavigationBarDelegate       public func navigationBar   navigationBar  UINavigationBar  shouldPop item  UINavigationItem  - gt  Bool           if let items   navigationBar items  viewControllers count  lt  items count               return true                    let clientInfoVC   topViewController as  ClientInfoVC         if clientInfoVC  responds to   selector clientInfoVC  navigationShouldPopOnBack      false               clientInfoVC  navigationShouldPopOnBack completion    isAllowPop in                 if isAllowPop                       DispatchQueue main async                           self popViewController animated  true                                                                            DispatchQueue main async               self popViewController animated  true                     return false           objc func navigationShouldPopOnBack completion   escaping  Bool  - gt                let ok   UIAlertAction title  R string alert actionOk    style   default      in             completion true                    let cancel   UIAlertAction title  R string alert actionCancel    style   cancel      in             completion false                    let alertController   UIAlertController title      message  R string alert contractMessage    preferredStyle   alert          alertController addAction ok          alertController addAction cancel          present alertController  animated  true  completion  nil

User · Answer

I was able to achieve this with the following    Swift 3  override func didMoveToParentViewController parent  UIViewController        super didMoveToParentViewController parent      if parent    nil         println  Back Button pressed          delegate  goingBack                       Swift 4   override func didMove toParent parent  UIViewController         super didMove toParent  parent       if parent    nil           debugPrint  Back Button pressed              No need of custom back button

User · Answer

Swift 4 2   override func viewWillDisappear   animated  Bool        super viewWillDisappear animated       if self isMovingFromParent              Your code

User · Answer

If you are using navigationController then add the UINavigationControllerDelegate protocol to class and add the delegate method as follows    class ViewController UINavigationControllerDelegate        func navigationController navigationController  UINavigationController  willShowViewController viewController  UIViewController  animated  Bool            if viewController     self                  do here what you want                     This method is called whenever the navigation controller will slide to a new screen  If the back button was pressed  the new view controller is ViewController itself

User · Answer

Replacing the button to a custom one as suggested on another answer is possibly not a great idea as you will lose the default behavior and style   One other option you have is to implement the viewWillDisappear method on the View Controller and check for a property named isMovingFromParentViewController  If that property is true  it means the View Controller is disappearing because it s being removed  popped    Should look something like   override func viewWillDisappear   animated  Bool        super viewWillDisappear animated       if self isMovingFromParentViewController              Your code              In swift 4 2  override func viewWillDisappear   animated  Bool        super viewWillDisappear animated       if self isMovingFromParent              Your code

User · Answer

just do control   drag the bar item to below func  work like charm   IBAction func done sender  AnyObject        if  self presentingViewController     nil           self dismiss animated  false  completion  nil          print  done

User · Answer

Swift 3   override func didMove toParentViewController parent  UIViewController         super didMove toParentViewController  parent       if parent    nil          print  Back button was clicked

User · Answer

In Swift 5 and Xcode 10 2  Please don t add custom bar button item  use this default behaviour    No need of viewWillDisappear  no need of custom BarButtonItem etc     It s better to detect when the VC is removed from it s parent   Use any one of these two functions  override func willMove toParent parent  UIViewController         super willMove toParent  parent      if parent    nil           callStatusDelegate  backButtonClicked    Here write your code          override func didMove toParent parent  UIViewController         super didMove toParent  parent      if parent    nil           callStatusDelegate  backButtonClicked    Here write your code           If you want stop default behaviour of back button then add custom BarButtonItem

User · Answer

Here is the simplest possible Swift 5 solution that doesn t require you to create a custom back button and give up all that UINavigationController left button functionality you get for free   As Brandon A recommends above  you need need to implement UINavigationControllerDelegate in the view controller you want to interact with before returning to it  A good way is to create an unwind segue that you can perform manually or automatically and reuse the same code from a custom done button or the back button   First  make your view controller of interest  the one you want to detect returning to  a delegate of the navigation controller in its viewDidLoad   override func viewDidLoad         super viewDidLoad       navigationController  delegate   self     Second  add an extension at the bottom of the file that overrides navigationController willShow animated    extension PickerTableViewController  UINavigationControllerDelegate        func navigationController   navigationController  UINavigationController                                willShow viewController  UIViewController                                animated  Bool             if let     viewController as  EditComicBookViewController                let selectedItemRow   itemList firstIndex of  selectedItemName              selectedItemIndex   IndexPath row  selectedItemRow   section  0               if let selectedCell   tableView cellForRow at  selectedItemIndex                    performSegue withIdentifier   PickedItem   sender  selectedCell                                    Since your question included a UITableViewController  I included a way to get the index path of the row the user tapped

User · Answer

I accomplished this by calling overriding viewWillDisappear and then accessing the stack of the navigationController like this    override func viewWillDisappear animated  Bool        super viewWillDisappear animated       let stack   self navigationController  viewControllers count      if stack  gt   2              for whatever reason  the last item on the stack is the TaskBuilderViewController  not self   so we only use -1 to access it         if let lastitem   self navigationController  viewControllers stack  - 1  as  theViewControllerYoureTryingToAccess                  hand over the data via public property or call a public method of theViewControllerYoureTryingToAccess  like             lastitem emptyArray               lastitem value   5

User · Answer

You can simply remove unnecessary controllers from the stack  something like this  self navigationController  viewControllers removeAll where             0 is FirstViewController     0 is SecondWithPinController

User · Answer

For Swift 5  we can check it in view will disappear  override func viewWillDisappear   animated  Bool        super viewWillDisappear animated       if self isMovingFromParent           delegate  passValue clickedImage  selectedImage

User · Answer

One option would be implementing your own custom back button  You would need to add the following code to your viewDidLoad method   -  void  viewDidLoad        super viewDidLoad       self navigationItem hidesBackButton   YES      UIBarButtonItem  newBackButton     UIBarButtonItem alloc  initWithTitle   Back  style UIBarButtonItemStyleBordered target self action  selector back         self navigationItem leftBarButtonItem   newBackButton     -  void  back  UIBarButtonItem   sender          Perform your custom actions                   Go back to the previous ViewController      self navigationController popViewControllerAnimated YES       UPDATE   Here is the version for Swift       override func viewDidLoad           super viewDidLoad           self navigationItem hidesBackButton   true         let newBackButton   UIBarButtonItem title   Back   style  UIBarButtonItemStyle Bordered  target  self  action   back            self navigationItem leftBarButtonItem   newBackButton            func back sender  UIBarButtonItem               Perform your custom actions                           Go back to the previous ViewController         self navigationController  popViewControllerAnimated true          UPDATE 2   Here is the version for Swift 3       override func viewDidLoad           super viewDidLoad           self navigationItem hidesBackButton   true         let newBackButton   UIBarButtonItem title   Back   style  UIBarButtonItemStyle plain  target  self  action   selector YourViewController back sender             self navigationItem leftBarButtonItem   newBackButton            func back sender  UIBarButtonItem               Perform your custom actions                           Go back to the previous ViewController             navigationController  popViewController animated  true

User · Answer

As I understand you want to empty your array as you press your back button and pop to your previous ViewController let your Array which you loaded on this screen is  let settingArray    NSMutableArray    IBAction func Back sender  AnyObject        self  settingArray removeAllObjects       self dismissViewControllerAnimated true  completion  nil

User · Answer

I created this  swift  class to create a back button exactly like the regular one  including back arrow  It can create a button with regular text or with an image   Usage  weak var weakSelf   self     Assign back button with back arrow and text  exactly like default back button  navigationItem leftBarButtonItems   CustomBackButton createWithText  YourBackButtonTitle   color  UIColor yourColor    target  weakSelf  action   selector YourViewController tappedBackButton       Assign back button with back arrow and image navigationItem leftBarButtonItems   CustomBackButton createWithImage UIImage named   yourImageName     color  UIColor yourColor    target  weakSelf  action   selector YourViewController tappedBackButton    func tappedBackButton             Do your thing      self navigationController  popViewControllerAnimated true      CustomBackButtonClass    code for drawing the back arrow created with Sketch  amp  Paintcode plugin   class CustomBackButton  NSObject        class func createWithText text  String  color  UIColor  target  AnyObject   action  Selector  - gt   UIBarButtonItem            let negativeSpacer   UIBarButtonItem barButtonSystemItem  UIBarButtonSystemItem FixedSpace  target  nil  action  nil          negativeSpacer width   -8         let backArrowImage   imageOfBackArrow color  color          let backArrowButton   UIBarButtonItem image  backArrowImage  style  UIBarButtonItemStyle Plain  target  target  action  action          let backTextButton   UIBarButtonItem title  text  style  UIBarButtonItemStyle Plain   target  target  action  action          backTextButton setTitlePositionAdjustment UIOffset horizontal  -12 0  vertical  0 0   forBarMetrics  UIBarMetrics Default          return  negativeSpacer  backArrowButton  backTextButton             class func createWithImage image  UIImage  color  UIColor  target  AnyObject   action  Selector  - gt   UIBarButtonItem               recommended maximum image height 22 points  i e  22  1x  44  2x  66  3x          let negativeSpacer   UIBarButtonItem barButtonSystemItem  UIBarButtonSystemItem FixedSpace  target  nil  action  nil          negativeSpacer width   -8         let backArrowImageView   UIImageView image  imageOfBackArrow color  color           let backImageView   UIImageView image  image          let customBarButton   UIButton frame  CGRectMake 0 0 22   backImageView frame width 22           backImageView frame   CGRectMake 22  0  backImageView frame width  backImageView frame height          customBarButton addSubview backArrowImageView          customBarButton addSubview backImageView          customBarButton addTarget target  action  action  forControlEvents   TouchUpInside          return  negativeSpacer  UIBarButtonItem customView  customBarButton              private class func drawBackArrow frame frame  CGRect   CGRect x  0  y  0  width  14  height  22   color  UIColor   UIColor hue  0 59  saturation  0 674  brightness  0 886  alpha  1   resizing  ResizingBehavior    AspectFit                General Declarations         let context   UIGraphicsGetCurrentContext                 Resize To Frame         CGContextSaveGState context          let resizedFrame   resizing apply rect  CGRect x  0  y  0  width  14  height  22   target  frame          CGContextTranslateCTM context  resizedFrame minX  resizedFrame minY          let resizedScale   CGSize width  resizedFrame width   14  height  resizedFrame height   22          CGContextScaleCTM context  resizedScale width  resizedScale height               Line         let line   UIBezierPath           line moveToPoint CGPoint x  9  y  9           line addLineToPoint CGPoint zero          CGContextSaveGState context          CGContextTranslateCTM context  3  11          line lineCapStyle    Square         line lineWidth   3         color setStroke           line stroke           CGContextRestoreGState context               Line Copy         let lineCopy   UIBezierPath           lineCopy moveToPoint CGPoint x  9  y  0           lineCopy addLineToPoint CGPoint x  0  y  9           CGContextSaveGState context          CGContextTranslateCTM context  3  2          lineCopy lineCapStyle    Square         lineCopy lineWidth   3         color setStroke           lineCopy stroke           CGContextRestoreGState context           CGContextRestoreGState context             private class func imageOfBackArrow size size  CGSize   CGSize width  14  height  22   color  UIColor   UIColor hue  0 59  saturation  0 674  brightness  0 886  alpha  1   resizing  ResizingBehavior    AspectFit  - gt  UIImage           var image  UIImage          UIGraphicsBeginImageContextWithOptions size  false  0          drawBackArrow frame  CGRect origin  CGPoint zero  size  size   color  color  resizing  resizing          image   UIGraphicsGetImageFromCurrentImageContext           UIGraphicsEndImageContext            return image            private enum ResizingBehavior           case AspectFit     The content is proportionally resized to fit into the target rectangle          case AspectFill     The content is proportionally resized to completely fill the target rectangle          case Stretch     The content is stretched to match the entire target rectangle          case Center     The content is centered in the target rectangle  but it is NOT resized           func apply rect rect  CGRect  target  CGRect  - gt  CGRect               if rect    target    target    CGRect zero                   return rect                            var scales   CGSize zero             scales width   abs target width   rect width              scales height   abs target height   rect height               switch self                   case  AspectFit                      scales width   min scales width  scales height                      scales height   scales width                 case  AspectFill                      scales width   max scales width  scales height                      scales height   scales width                 case  Stretch                      break                 case  Center                      scales width   1                     scales height   1                            var result   rect standardized             result size width    scales width             result size height    scales height             result origin x   target minX    target width - result width    2             result origin y   target minY    target height - result height    2             return result                     SWIFT 3 0  class CustomBackButton  NSObject        class func createWithText text  String  color  UIColor  target  AnyObject   action  Selector  - gt   UIBarButtonItem            let negativeSpacer   UIBarButtonItem barButtonSystemItem  UIBarButtonSystemItem fixedSpace  target  nil  action  nil          negativeSpacer width   -8         let backArrowImage   imageOfBackArrow color  color          let backArrowButton   UIBarButtonItem image  backArrowImage  style  UIBarButtonItemStyle plain  target  target  action  action          let backTextButton   UIBarButtonItem title  text  style  UIBarButtonItemStyle plain   target  target  action  action          backTextButton setTitlePositionAdjustment UIOffset horizontal  -12 0  vertical  0 0   for  UIBarMetrics default          return  negativeSpacer  backArrowButton  backTextButton             class func createWithImage image  UIImage  color  UIColor  target  AnyObject   action  Selector  - gt   UIBarButtonItem               recommended maximum image height 22 points  i e  22  1x  44  2x  66  3x          let negativeSpacer   UIBarButtonItem barButtonSystemItem  UIBarButtonSystemItem fixedSpace  target  nil  action  nil          negativeSpacer width   -8         let backArrowImageView   UIImageView image  imageOfBackArrow color  color           let backImageView   UIImageView image  image          let customBarButton   UIButton frame  CGRect x  0  y  0  width  22   backImageView frame width  height  22           backImageView frame   CGRect x  22  y  0  width  backImageView frame width  height  backImageView frame height          customBarButton addSubview backArrowImageView          customBarButton addSubview backImageView          customBarButton addTarget target  action  action  for   touchUpInside          return  negativeSpacer  UIBarButtonItem customView  customBarButton              private class func drawBackArrow   frame  CGRect   CGRect x  0  y  0  width  14  height  22   color  UIColor   UIColor hue  0 59  saturation  0 674  brightness  0 886  alpha  1   resizing  ResizingBehavior    AspectFit                General Declarations         let context   UIGraphicsGetCurrentContext                 Resize To Frame         context saveGState           let resizedFrame   resizing apply CGRect x  0  y  0  width  14  height  22   target  frame          context translateBy x  resizedFrame minX  y  resizedFrame minY          let resizedScale   CGSize width  resizedFrame width   14  height  resizedFrame height   22          context scaleBy x  resizedScale width  y  resizedScale height               Line         let line   UIBezierPath           line move to  CGPoint x  9  y  9           line addLine to  CGPoint zero          context saveGState           context translateBy x  3  y  11          line lineCapStyle    square         line lineWidth   3         color setStroke           line stroke           context restoreGState                Line Copy         let lineCopy   UIBezierPath           lineCopy move to  CGPoint x  9  y  0           lineCopy addLine to  CGPoint x  0  y  9           context saveGState           context translateBy x  3  y  2          lineCopy lineCapStyle    square         lineCopy lineWidth   3         color setStroke           lineCopy stroke           context restoreGState            context restoreGState              private class func imageOfBackArrow   size  CGSize   CGSize width  14  height  22   color  UIColor   UIColor hue  0 59  saturation  0 674  brightness  0 886  alpha  1   resizing  ResizingBehavior    AspectFit  - gt  UIImage           var image  UIImage          UIGraphicsBeginImageContextWithOptions size  false  0          drawBackArrow CGRect origin  CGPoint zero  size  size   color  color  resizing  resizing          image   UIGraphicsGetImageFromCurrentImageContext            UIGraphicsEndImageContext            return image            private enum ResizingBehavior           case AspectFit     The content is proportionally resized to fit into the target rectangle          case AspectFill     The content is proportionally resized to completely fill the target rectangle          case Stretch     The content is stretched to match the entire target rectangle          case Center     The content is centered in the target rectangle  but it is NOT resized           func apply   rect  CGRect  target  CGRect  - gt  CGRect               if rect    target    target    CGRect zero                   return rect                            var scales   CGSize zero             scales width   abs target width   rect width              scales height   abs target height   rect height               switch self               case  AspectFit                  scales width   min scales width  scales height                  scales height   scales width             case  AspectFill                  scales width   max scales width  scales height                  scales height   scales width             case  Stretch                  break             case  Center                  scales width   1                 scales height   1                            var result   rect standardized             result size width    scales width             result size height    scales height             result origin x   target minX    target width - result width    2             result origin y   target minY    target height - result height    2             return result

User · Answer

Try this    self navigationItem leftBarButtonItem  target    methodname  func methodname                           enter code here     Try on this too    override func viewWillAppear animated  Bool        empty your array

User · Answer

You can subclass UINavigationController and override popViewController animated  Bool   Beside being able to execute some code there you can also prevent the user from going back altogether  for instance to prompt to save or discard his current work   Sample implementation where you can set a popHandler that gets set cleared by pushed controllers   class NavigationController  UINavigationController       var popHandler      - gt  Bool        override func popViewController animated  Bool  - gt  UIViewController                guard self popHandler       false else                       return nil                   self popHandler   nil         return super popViewController animated  animated            And sample usage from a pushed controller that tracks unsaved work   let hasUnsavedWork  Bool           self navigationController as  NavigationController  popHandler   hasUnsavedWork                    Prompt saving work here with an alert          return false    Prevent pop until as user choses to save or discard          nil    No unsaved work  we clear popHandler to let it pop normally   As a nice touch  this will also get called by interactivePopGestureRecognizer when the user tries to go back using a swipe gesture

User · Answer

override func viewWillDisappear   animated  Bool        super viewWillDisappear animated       if self isMovingToParent              your code backView

User · Answer

In my case the viewWillDisappear worked best  But in some cases one has to modify the previous view controller  So here is my solution with access to the previous view controller and it works in Swift 4   override func viewWillDisappear   animated  Bool            super viewWillDisappear animated          if isMovingFromParentViewController               if let viewControllers   self navigationController  viewControllers                   if  viewControllers count  gt   1                        let previousViewController   viewControllers viewControllers count-1  as  NameOfDestinationViewController                        whatever you want to do                     previousViewController callOrModifySomething

User · Answer

override func willMove toParent parent  UIViewController         super willMove toParent  parent      if parent    nil               print  This VC is  will  be popped  i e  the back button was pressed

User · Answer

If you want to have back button with back arrow you can use an image and code below  backArrow png  backArrow 2x png  backArrow 3x png   override func viewDidLoad         super viewDidLoad       let customBackButton   UIBarButtonItem image  UIImage named   backArrow     style   plain  target  self  action   selector backAction sender         customBackButton imageInsets   UIEdgeInsets top  2  left  -8  bottom  0  right  0      navigationItem leftBarButtonItem   customBackButton    func backAction sender  UIBarButtonItem           custom actions here     navigationController  popViewController animated  true

User · Answer

override public func viewDidLoad              super viewDidLoad            self navigationController  navigationBar topItem  title   GlobalVariables selectedMainIconName          let image   UIImage named   back-btn             image   image  imageWithRenderingMode UIImageRenderingMode AlwaysOriginal           self navigationItem leftBarButtonItem   UIBarButtonItem image  image  style  UIBarButtonItemStyle Plain  target  self  action   selector Current enter image description here  1 ViewController back               func back           self navigationController  popToViewController  self navigationController  viewControllers  self navigationController  viewControllers count - 2    animated  true

User · Answer

This is how I solved it for my own problem  override func viewWillAppear   animated  Bool        super viewWillAppear animated      self navigationItem leftBarButtonItem  action    selector self back sender        self navigationItem leftBarButtonItem  target   self     objc func back sender  UIBarButtonItem

User · Answer

It s not difficult as we thing  Just create a frame for UIButton with clear background color  assign action for the button and place over the navigationbar back button  And finally remove the button after use   Here is the Swift 3 sample code done with UIImage instead of UIButton   override func viewDidLoad         super viewDidLoad       let imageView   UIImageView       imageView backgroundColor   UIColor clear     imageView frame   CGRect x 0 y 0 width 2  self navigationController  navigationBar bounds height   height  self navigationController  navigationBar bounds height        let tapGestureRecognizer   UITapGestureRecognizer target  self  action   selector back sender         imageView isUserInteractionEnabled   true     imageView addGestureRecognizer tapGestureRecognizer      imageView tag   1     self navigationController  navigationBar addSubview imageView          write the code need  to be executed    func back sender  UIBarButtonItem            Perform your custom actions          self navigationController  popViewController animated  true           Remove the subView after action is performed  override func viewWillDisappear   animated  Bool        super viewWillDisappear animated       for view in  self navigationController  navigationBar subviews            if view tag    1               view removeFromSuperview

User · Answer

You can do something in your Viewcontroller like  override func navigationShouldPopOnBackButton   - gt  Bool       self backAction     Your action you want to perform      return true     For complete answer use Detecting when the   39 back  39  button is pressed on a navbar

User · Answer

NO  override func willMove toParentViewController parent  UIViewController        This will get called even if you are segueing to the view controller in which you are overriding this method  In which check if the  parent  is nil of not is not a precise way to be sure of moving back to the correct UIViewController  To determine exactly if the UINavigationController is properly navigating back to the UIViewController that presented this current one  you will need to conform to the UINavigationControllerDelegate protocol   YES  note  MyViewController is just the name of whatever UIViewController you want to detect going back from   1  At the top of your file add UINavigationControllerDelegate   class MyViewController  UIViewController  UINavigationControllerDelegate     2  Add a property to your class that will keep track of the UIViewController that you are segueing from   class MyViewController  UIViewController  UINavigationControllerDelegate    var previousViewController UIViewController   3  in MyViewController s viewDidLoad method assign self as the delegate for your UINavigationController   override func viewDidLoad         super viewDidLoad       self navigationController  delegate   self     3  Before you segue  assign the previous UIViewController as this property      In previous UIViewController override func prepare for segue  UIStoryboardSegue  sender  Any         if segue identifier     YourSegueID            if let nextViewController   segue destination as  MyViewController               nextViewController previousViewController   self                     4  And conform to one method in MyViewController of the UINavigationControllerDelegate  func navigationController   navigationController  UINavigationController  willShow viewController  UIViewController  animated  Bool        if viewController    self previousViewController              You are going back

[ios] Execute action when back bar button of UINavigationController is pressed

Swift 5 __ Xcode 11.5

Examples related to ios

Examples related to xcode

Examples related to swift

Examples related to uinavigationcontroller