Get to UIViewController from UIView

Question

Is there a built-in way to get from a UIView to its UIViewController  I know you can get from UIViewController to its UIView via  self view  but I was wondering if there is a reverse reference

User · Answer

I would suggest a more lightweight approach for traversing the complete responder chain without having to add a category on UIView    implementation MyUIViewSubclass  -  UIViewController   viewController       UIResponder  responder   self      while    responder isKindOfClass  UIViewController class              responder    responder nextResponder           if  nil    responder                break                      return  UIViewController   responder      end

User · Answer

Swift 4 version  extension UIView   var parentViewController  UIViewController        var parentResponder  UIResponder    self     while parentResponder    nil           parentResponder   parentResponder  next         if let viewController   parentResponder as  UIViewController               return viewController                     return nil     Usage example   if let parent   self view parentViewController

User · Answer

There is no way   What I do is pass the UIViewController pointer to the UIView  or an appropriate inheritance   I m sorry I can t help with the IB approach to the problem because I don t believe in IB   To answer the first commenter  sometimes you do need to know who called you because it determines what you can do  For example with a database you might have read access only or read write

User · Answer

Combining several already given answers  I m shipping on it as well with my implementation    implementation UIView  AppNameAdditions   -  UIViewController   appName viewController           Finds the view s view controller          Take the view controller class object here and avoid sending the same message iteratively unnecessarily      Class vcc    UIViewController class           Traverse responder chain  Return first found view controller  which will be the view s view controller      UIResponder  responder   self      while   responder    responder nextResponder            if   responder isKindOfClass  vcc               return  UIViewController   responder          If the view controller isn t found  return nil      return nil      end   The category is part of my ARC-enabled static library that I ship on every application I create  It s been tested several times and I didn t find any problems or leaks   P S   You don t need to use a category like I did if the concerned view is a subclass of yours  In the latter case  just put the method in your subclass and you re good to go

User · Answer

Using the example posted by Brock  I modified it so that it is a category of UIView instead UIViewController and made it recursive so that any subview can  hopefully  find the parent UIViewController    interface UIView  FindUIViewController  -  UIViewController    firstAvailableUIViewController  -  id  traverseResponderChainForUIViewController   end   implementation UIView  FindUIViewController  -  UIViewController    firstAvailableUIViewController          convenience function for casting and to  mask  the recursive function     return  UIViewController    self traverseResponderChainForUIViewController      -  id  traverseResponderChainForUIViewController       id nextResponder    self nextResponder       if   nextResponder isKindOfClass  UIViewController class              return nextResponder        else if   nextResponder isKindOfClass  UIView class              return  nextResponder traverseResponderChainForUIViewController         else           return nil           end   To use this code  add it into an new class file  I named mine  UIKitCategories   and remove the class data    copy the  interface into the header  and the  implementation into the  m file   Then in your project   import  UIKitCategories h  and use within the UIView code      from a UIView subclass    returns nil if UIViewController not available UIViewController   myController    self firstAvailableUIViewController

User · Answer

Maybe I m late here  But in this situation I don t like category  pollution   I love this way    define UIViewParentController   view       UIResponder    responder     view    while     responder isKindOfClass  UIView class        responder      responder nextResponder      UIViewController     responder

User · Answer

Another easy way is to have your own view class and add a property of the view controller in the view class  Usually the view controller creates the view and that is where the controller can set itself to the property  Basically it is instead of searching around  with a bit of hacking  for the controller  having the controller to set itself to the view - this is simple but makes sense because it is the controller that  controls  the view

User · Answer

Swift 4   more concise than the other answers   fileprivate extension UIView      var firstViewController  UIViewController        let firstViewController   sequence first  self  next     0 next    first where     0 is UIViewController        return firstViewController as  UIViewController          My use case for which I need to access the view first UIViewController  I have an object that wraps around AVPlayer   AVPlayerViewController and I want to provide a simple show in view  UIView  method that will embed AVPlayerViewController into view  For that  I need to access view s UIViewController

User · Answer

If your rootViewController is UINavigationViewController  which was set up in AppDelegate class  then         UIViewController    getNearestViewController  Class  c   NSArray  arrVc       UIApplication sharedApplication  keyWindow  rootViewController  childViewControllers    for  UIViewController  v in arrVc        if   v isKindOfClass c                 return v           return nil     Where c required view controllers class   USAGE        RequiredViewController  rvc    Utilities getNearestViewController  RequiredViewController class

User · Answer

My solution would probably be considered kind of bogus but I had a similar situation as mayoneez  I wanted to switch views in response to a gesture in an EAGLView   and I got the EAGL s view controller this way   EAGLViewController  vc     EAGLAppDelegate    UIApplication sharedApplication  delegate   viewController

User · Answer

The simplest do while loop for finding the viewController   - UIViewController  viewController       UIResponder  nextResponder    self       do               nextResponder    nextResponder nextResponder            if   nextResponder isKindOfClass  UIViewController class                return  UIViewController  nextResponder         while  nextResponder    nil        return nil

User · Answer

var parentViewController  UIViewController        let s   sequence first  self     0 next       return s compactMap    0 as  UIViewController   first

User · Answer

This doesn t answer the question directly  but rather makes an assumption about the intent of the question   If you have a view and in that view you need to call a method on another object  like say the view controller  you can use the NSNotificationCenter instead   First create your notification string in a header file   define SLCopyStringNotification   ShaoloCopyStringNotification    In your view call postNotificationName   -  IBAction  copyString  id sender         NSNotificationCenter defaultCenter  postNotificationName SLCopyStringNotification object nil       Then in your view controller you add an observer   I do this in viewDidLoad  -  void viewDidLoad         NSNotificationCenter defaultCenter  addObserver self                                              selector  selector copyString                                                    name SLCopyStringNotification                                                object nil       Now  also in the same view controller  implement your method copyString  as depicted in the  selector above   -  IBAction  copyString  id sender       CalculatorResult  result    CalculatorResult    PercentCalculator sharedInstance  arrayTableDS objectAtIndex   self viewTableResults indexPathForSelectedRow  row        UIPasteboard  gpBoard    UIPasteboard generalPasteboard        gpBoard setString result stringResult       I m not saying this is the right way to do this  it just seems cleaner than running up the first responder chain   I used this code to implement a UIMenuController on a UITableView and pass the event back up to the UIViewController so I can do something with the data

User · Answer

UIView is a subclass of UIResponder  UIResponder lays out the method -nextResponder with an implementation that returns nil  UIView overrides this method  as documented in UIResponder  for some reason instead of in UIView  as follows  if the view has a view controller  it is returned by -nextResponder  If there is no view controller  the method will return the superview    Add this to your project and you re ready to roll     interface UIView  APIFix  -  UIViewController   viewController   end   implementation UIView  APIFix   -  UIViewController   viewController       if   self nextResponder isKindOfClass UIViewController class           return  UIViewController   self nextResponder      else         return nil     end   Now UIView has a working method for returning the view controller

User · Answer

I stumbled upon a situation where I have a small component I want to reuse  and added some code in a reusable  view itself it s really not much more than a button that opens a PopoverController    While this works fine in the iPad  the UIPopoverController presents itself  therefor needs no reference to a UIViewController   getting the same code to work means suddenly referencing your presentViewController from your UIViewController  Kinda inconsistent right   Like mentioned before  it s not the best approach to have logic in your UIView  But it felt really useless to wrap the few lines of code needed in a separate controller   Either way  here s a swift solution  which adds a new property to any UIView   extension UIView        var viewController  UIViewController             var responder  UIResponder    self          while responder    nil                if let responder   responder as  UIViewController                   return responder                           responder   responder  nextResponder                     return nil

User · Answer

To get the controller of a given view  one can use UIFirstResponder chain   customView target forAction  Selector  viewDidLoad    withSender  nil

User · Answer

It s surely a bad idea and a wrong design  but I m sure we can all enjoy a Swift solution of the best answer proposed by  Phil M   static func firstAvailableUIViewController fromResponder responder  UIResponder  - gt  UIViewController        func traverseResponderChainForUIViewController responder  UIResponder  - gt  UIViewController            if let nextResponder   responder nextResponder                 if let nextResp   nextResponder as  UIViewController                   return nextResp               else                   return traverseResponderChainForUIViewController nextResponder                                  return nil            return traverseResponderChainForUIViewController responder      If your intention is to do simple things  as showing a modal dialog or tracking data  that doesn t justify the use of a protocol  I personally store this function in an utility object  you can use it from anything that implement the UIResponder protocol as   if let viewController   MyUtilityClass firstAvailableUIViewController self       All credit to  Phil M

User · Answer

If you aren t going to upload this to the App Store  you can also use a private method of UIView    interface UIView Private  -  UIViewController    viewControllerForAncestor   end     Later in the code UIViewController  vc    myView  viewControllerForAncestor

User · Answer

Since this has been the accepted answer for a long time  I feel I need to rectify it with a better answer   Some comments on the need    Your view should not need to access the view controller directly  The view should instead be independent of the view controller  and be able to work in different contexts  Should you need the view to interface in a way with the view controller  the recommended way  and what Apple does across Cocoa is to use the delegate pattern    An example of how to implement it follows    protocol MyViewDelegate  lt  NSObject  gt   -  void viewActionHappened    end   interface MyView   UIView   property  nonatomic  assign  MyViewDelegate delegate    end   interface MyViewController  lt  MyViewDelegate  gt    end   The view interfaces with its delegate  as UITableView does  for instance  and it doesn t care if its implemented in the view controller or in any other class that you end up using   My original answer follows  I don t recommend this  neither the rest of the answers where direct access to the view controller is achieved  There is no built-in way to do it  While you can get around it by adding a IBOutlet on the UIView and connecting these in Interface Builder  this is not recommended  The view should not know about the view controller  Instead  you should do as  Phil M suggests and create a protocol to be used as the delegate

User · Answer

To Phil s answer   In line   id nextResponder    self nextResponder    if self UIView  is not a subview of ViewController s view  if you know hierarchy of self UIView  you can use also  id nextResponder     self superview  nextResponder

User · Answer

Don t forget that you can get access to the root view controller for the window that the view is a subview of  From there  if you are e g  using a navigation view controller and want to push a new view onto it           self window  rootViewController  navigationController  pushViewController newController animated YES     You will need to set up the rootViewController property of the window properly first  however  Do this when you first create the controller e g  in your app delegate   - void  applicationDidFinishLaunching  UIApplication   application       window     UIWindow alloc  initWithFrame   UIScreen mainScreen  bounds        RootViewController  controller     YourRootViewController  alloc  init        window setRootViewController  controller       navigationController     UINavigationController alloc  initWithRootViewController rootViewController        controller release        window addSubview   self navigationController  view         window makeKeyAndVisible

User · Answer

Updated version for swift 4   Thanks for  Phil M and  paul-slm  static func firstAvailableUIViewController fromResponder responder  UIResponder  - gt  UIViewController        func traverseResponderChainForUIViewController responder  UIResponder  - gt  UIViewController            if let nextResponder   responder next               if let nextResp   nextResponder as  UIViewController                   return nextResp               else                   return traverseResponderChainForUIViewController responder  nextResponder                                  return nil            return traverseResponderChainForUIViewController responder  responder

User · Answer

Swiftier solution  extension UIView       var parentViewController  UIViewController            for responder in sequence first  self  next     0 next                  if let viewController   responder as  UIViewController                   return viewController                                 return nil

User · Answer

While these answers are technically correct  including Ushox  I think the approved way is to implement a new protocol or re-use an existing one  A protocol insulates the observer from the observed  sort of like putting a mail slot in between them  In effect  that is what Gabriel does via the pushViewController method invocation  the view  knows  that it is proper protocol to politely ask your navigationController to push a view  since the viewController conforms to the navigationController protocol  While you can create your own protocol  just using Gabriel s example and re-using the UINavigationController protocol is just fine

User · Answer

I don t think it s  bad  idea to find out who is the view controller for some cases  What could be a bad idea is to save the reference to this controller as it could change just as superviews change  In my case I have a getter that traverses the responder chain      h   property  nonatomic  readonly  UIViewController   viewController       m  -  UIViewController   viewController       for  UIResponder   nextResponder   self nextResponder           nextResponder           nextResponder   nextResponder nextResponder                if   nextResponder isKindOfClass  UIViewController class                return  UIViewController   nextResponder                Not found     NSLog      doesn t seem to have a viewController   self       return nil

User · Answer

Two solutions as of Swift 5 2    More on the functional side No need for the return keyword now    Solution 1   extension UIView       var parentViewController  UIViewController            sequence first  self     0 next                first where     0 is UIViewController                 flatMap    0 as  UIViewController               Solution 2   extension UIView       var parentViewController  UIViewController            sequence first  self     0 next                compactMap   0 as  UIViewController                first            This solution requires iterating through each responder first  so may not be the most performant

User · Answer

Even though this can technically be solved as pgb recommends  IMHO  this is a design flaw  The view should not need to be aware of the controller

User · Answer

I think there is a case when the observed needs to inform the observer   I see a similar problem where the UIView in a UIViewController is responding to a situation and it needs to first tell its parent view controller to hide the back button and then upon completion tell the parent view controller that it needs to pop itself off the stack   I have been trying this with delegates with no success   I don t understand why this should be a bad idea

User · Answer

I modified de answer so I can pass any view  button  label etc  to get it s parent UIViewController  Here is my code      UIViewController   viewController  id view       UIResponder  responder   view      while    responder isKindOfClass  UIViewController class              responder    responder nextResponder           if  nil    responder                break                      return  UIViewController   responder      Edit Swift 3 Version  class func viewController   view  UIView  - gt  UIViewController           var responder  UIResponder    view         while   responder is UIViewController                responder   responder  next             if nil    responder                   break                                 return  responder as  UIViewController           Edit 2 - Swift Extention  extension UIView         Get Parent View Controller from any view     func parentViewController   - gt  UIViewController           var responder  UIResponder    self         while   responder is UIViewController                responder   responder  next             if nil    responder                   break                                 return  responder as  UIViewController

[ios] Get to UIViewController from UIView?

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