Get the current first responder without using a private API

Question

I submitted my app a little over a week ago and got the dreaded rejection email today  It tells me that my app cannot be accepted because I m using a non-public API  specifically  it says      The non-public API that is included in your application is firstResponder    Now  the offending API call is actually a solution I found here on SO   UIWindow  keyWindow     UIApplication sharedApplication  keyWindow   UIView    firstResponder    keyWindow performSelector  selector firstResponder      How do I get the current first responder on the screen  I m looking for a way that won t get my app rejected

User · Answer

Here is a Extension implemented in Swift based on Jakob Egger s most excellent answer  import UIKit  extension UIResponder          Swift 1 2 finally supports static vars   If you use 1 1 see          http   stackoverflow com a 24924535 385979     private weak static var  currentFirstResponder  UIResponder    nil          public class func currentFirstResponder   - gt  UIResponder            UIResponder  currentFirstResponder   nil         UIApplication sharedApplication   sendAction  quot findFirstResponder  quot   to  nil  from  nil  forEvent  nil          return UIResponder  currentFirstResponder                internal func findFirstResponder sender  AnyObject            UIResponder  currentFirstResponder   self           Swift 4 import UIKit      extension UIResponder       private weak static var  currentFirstResponder  UIResponder    nil          public static var current  UIResponder            UIResponder  currentFirstResponder   nil         UIApplication shared sendAction  selector findFirstResponder sender     to  nil  from  nil  for  nil          return UIResponder  currentFirstResponder                 objc internal func findFirstResponder sender  AnyObject            UIResponder  currentFirstResponder   self

User · Answer

For a Swift 3  amp  4 version of nevyn s answer   UIApplication shared sendAction  selector UIView resignFirstResponder   to  nil  from  nil  for  nil

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This is what I did to find what UITextField is the firstResponder when the user clicks Save Cancel in a ModalViewController        NSArray  subviews    self tableView subviews    for  id cell in subviews          if   cell isKindOfClass  UITableViewCell class                   UITableViewCell  aCell   cell          NSArray  cellContentViews     aCell contentView  subviews           for  id textField in cellContentViews                         if   textField isKindOfClass  UITextField class                                   UITextField  theTextField   textField                  if   theTextField isFirstResponder                          theTextField resignFirstResponder

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You can choose the following UIView extension to get it  credit by Daniel    extension UIView       var firstResponder  UIView            guard  isFirstResponder else   return self           return subviews first where    0 firstResponder    nil

User · Answer

Here s a solution which reports the correct first responder  many other solutions won t report a UIViewController as the first responder  for example   doesn t require looping over the view hierarchy  and doesn t use private APIs   It leverages Apple s method sendAction to from forEvent   which already knows how to access the first responder   We just need to tweak it in 2 ways    Extend UIResponder so it can execute our own code on the first responder  Subclass UIEvent in order to return the first responder    Here is the code    interface ABCFirstResponderEvent   UIEvent  property  nonatomic  strong  UIResponder  firstResponder   end   implementation ABCFirstResponderEvent  end   implementation UIResponder  ABCFirstResponder  -  void abc findFirstResponder  id sender event  ABCFirstResponderEvent   event       event firstResponder   self     end   implementation ViewController     UIResponder   firstResponder       ABCFirstResponderEvent  event    ABCFirstResponderEvent new         UIApplication sharedApplication  sendAction  selector abc findFirstResponder event   to nil from nil forEvent event       return event firstResponder      end

User · Answer

You can try also like this   -  void  touchesBegan   NSSet    touches withEvent   UIEvent    event         for  id textField in self view subviews             if   textField isKindOfClass  UITextField class    amp  amp   textField isFirstResponder                  textField resignFirstResponder                        I didn t try it but it seems a good solution

User · Answer

Simplest way to find first responder   func sendAction   action  Selector  to target  Any   from sender  Any   for event  UIEvent   - gt  Bool      The default implementation dispatches the action method to the given   target object or  if no target is specified  to the first responder    Next step   extension UIResponder       private weak static var first  UIResponder    nil       objc     private func firstResponderWhereYouAre sender  AnyObject                UIResponder first   self            static var actualFirst  UIResponder                UIApplication shared sendAction  selector findFirstResponder sender     to  nil  from  nil  for  nil          return UIResponder first           Usage  Just get UIResponder actualFirst for your own purposes

User · Answer

A common way of manipulating the first responder is to use nil targeted actions  This is a way of sending an arbitrary message to the responder chain  starting with the first responder   and continuing down the chain until someone responds to the message  has implemented a method matching the selector    For the case of dismissing the keyboard  this is the most effective way that will work no matter which window or view is first responder     UIApplication sharedApplication  sendAction  selector resignFirstResponder  to nil from nil forEvent nil     This should be more effective than even  self view window endEditing YES     Thanks to BigZaphod for reminding me of the concept

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In one of my applications I often want the first responder to resign if the user taps on the background  For this purpose I wrote a category on UIView  which I call on the UIWindow   The following is based on that and should return the first responder    implementation UIView  FindFirstResponder  -  id findFirstResponder       if  self isFirstResponder            return self                    for  UIView  subView in self subviews            id responder    subView findFirstResponder           if  responder  return responder            return nil     end   iOS 7    -  id findFirstResponder       if  self isFirstResponder            return self            for  UIView  subView in self view subviews            if   subView isFirstResponder                 return subView                      return nil      Swift   extension UIView       var firstResponder  UIView            guard  isFirstResponder else   return self            for subview in subviews               if let firstResponder   subview firstResponder                   return firstResponder                                  return nil           Usage example in Swift   if let firstResponder   view window  firstResponder          do something with  firstResponder

User · Answer

If you just need to kill the keyboard when the user taps on a background area why not add a gesture recognizer and use it to send the   self view  endEditing YES  message   you can add the Tap gesture recogniser in the xib or storyboard file and connect it to an action   looks something like this then finished  -  IBAction displayGestureForTapRecognizer  UITapGestureRecognizer   recognizer         self view  endEditing YES

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Here s a category that allows you to quickly find the first responder by calling  UIResponder currentFirstResponder   Just add the following two files to your project   UIResponder FirstResponder h   import  lt Cocoa Cocoa h gt   interface UIResponder  FirstResponder        id currentFirstResponder   end   UIResponder FirstResponder m   import  UIResponder FirstResponder h  static   weak id currentFirstResponder   implementation UIResponder  FirstResponder        id currentFirstResponder            currentFirstResponder   nil             UIApplication sharedApplication  sendAction  selector findFirstResponder   to nil from nil forEvent nil            return currentFirstResponder            - void findFirstResponder  id sender           currentFirstResponder   self         end   The trick here is that sending an action to nil sends it to the first responder    I originally published this answer here  https   stackoverflow com a 14135456 322427

User · Answer

Iterate over the views that could be the first responder and use -  BOOL isFirstResponder to determine if they currently are

User · Answer

I have a slightly different approach than most   Rather than iterate through the collection of views looking for the one that has isFirstResponder set  I too send a message to nil  but I store the receiver of the message so I can return it and do whatever I wish with it  import UIKit  private var  foundFirstResponder  UIResponder    nil  extension UIResponder        static var first UIResponder                Sending an action to  nil  implicitly sends it to the first responder            where we simply capture it and place it in the  foundFirstResponder variable             As such  the variable will contain the current first responder  if any  immediately after this line executes         UIApplication shared sendAction  selector UIResponder storeFirstResponder       to  nil  from  nil  for  nil              The following  defer  statement runs  after  this getter returns             thus releasing any strong reference held by the variable immediately thereafter         defer                foundFirstResponder   nil                       Return the found first-responder  if any  back to the caller         return  foundFirstResponder             objc func storeFirstResponder   sender  AnyObject                Capture the recipient of this message  self   which is the first responder          foundFirstResponder   self          With the above  I can resign the first responder by simply doing this    UIResponder first  resignFirstResponder    But since my API actually hands back whatever the first responder is  I can do whatever I want with it  Here s an example that checks if the current first responder is a UITextField with a helpMessage property set  and if so  shows it in a help bubble right next to the control  We call this from a  Quick Help  button on our screen  func showQuickHelp         if let textField     UIResponder  first as  UITextField         let helpMessage   textField helpMessage                textField showHelpBubble with helpMessage           The support for the above is defined in an extension on UITextField like so    extension UITextField       var helpMessage String              func showHelpBubble with message String             Now to support this feature  all we have to do is decide which text fields have help messages and the UI takes care of the rest for us

User · Answer

With a category on UIResponder  it is possible to legally ask the UIApplication object to tell you who the first responder is   See this   Is there any way of asking an iOS view which of its children has first responder status

User · Answer

The first responder can be any instance of the class UIResponder  so there are other classes that might be the first responder despite the UIViews  For example UIViewController might also be the first responder    In this gist you will find a recursive way to get the first responder by looping through the hierarchy of controllers starting from the rootViewController of the application s windows   You can retrieve then the first responder by doing  -  void foo          Get the first responder     id firstResponder    UIResponder firstResponder           Do whatever you want      firstResponder resignFirstResponder             However  if the first responder is not a subclass of UIView or UIViewController  this approach will fail   To fix this problem we can do a different approach by creating a category on UIResponder and perform some magic swizzeling to be able to build an array of all living instances of this class  Then  to get the first responder we can simple iterate and ask each object if -isFirstResponder   This approach can be found implemented in this other gist   Hope it helps

User · Answer

Update  I was wrong  You can indeed use UIApplication shared sendAction   to from for   to call the first responder demonstrated in this link  http   stackoverflow com a 14135456 746890     Most of the answers here can t really find the current first responder if it is not in the view hierarchy  For example  AppDelegate or UIViewController subclasses   There is a way to guarantee you to find it even if the first responder object is not a UIView   First lets implement a reversed version of it  using the next property of UIResponder   extension UIResponder       var nextFirstResponder  UIResponder            return isFirstResponder   self   next  nextFirstResponder           With this computed property  we can find the current first responder from bottom to top even if it s not UIView  For example  from a view to the UIViewController who s managing it  if the view controller is the first responder   However  we still need a top-down resolution  a single var to get the current first responder   First with the view hierarchy   extension UIView       var previousFirstResponder  UIResponder            return nextFirstResponder    subviews compactMap    0 previousFirstResponder   first           This will search for the first responder backwards  and if it couldn t find it  it would tell its subviews to do the same thing  because its subview s next is not necessarily itself   With this we can find it from any view  including UIWindow   And finally  we can build this   extension UIResponder       static var first  UIResponder            return UIApplication shared windows compactMap    0 previousFirstResponder    first           So when you want to retrieve the first responder  you can call   let firstResponder   UIResponder first

User · Answer

Peter Steinberger just tweeted about the private notification UIWindowFirstResponderDidChangeNotification  which you can observe if you want to watch the firstResponder change

User · Answer

I would like to shared with you my implementation for find first responder in anywhere of UIView  I hope it helps and sorry for my english  Thanks     UIView    findFirstResponder  UIView     view        UIView  retorno       for  id subView in  view subviews             if   subView isFirstResponder           return subView           if   subView isKindOfClass  UIView class                  UIView  v   subView               if   v subviews count   gt  0                    retorno    self findFirstResponder v                   if   retorno isFirstResponder                         return retorno                                                       return retorno

User · Answer

Swift version of  thomas-m  ller s response  extension UIView        func firstResponder   - gt  UIView            if self isFirstResponder                 return self                    for subview in self subviews               if let firstResponder   subview firstResponder                     return firstResponder                                  return nil

User · Answer

If your ultimate aim is just to resign the first responder  this should work   self view endEditing YES

User · Answer

It s not pretty  but the way I resign the firstResponder when I don t know what that the responder is   Create an UITextField  either in IB or programmatically  Make it Hidden  Link it up to your code if you made it in IB   Then  when you want to dismiss the keyboard  you switch the responder to the invisible text field  and immediately resign it        self invisibleField becomeFirstResponder        self invisibleField resignFirstResponder

User · Answer

This is good candidate for recursion  No need to add a category to UIView   Usage  from your view controller    UIView  firstResponder    self findFirstResponder  self view      Code      This is a recursive function -  UIView   findFirstResponder  UIView   view        if   view isFirstResponder   return view     Base case      for  UIView  subView in  view subviews             if   self findFirstResponder subView   return subView     Recursion           return nil

User · Answer

Just it case here is Swift version of awesome Jakob Egger s approach   import UIKit  private weak var currentFirstResponder  UIResponder   extension UIResponder        static func firstResponder   - gt  UIResponder            currentFirstResponder   nil         UIApplication sharedApplication   sendAction  selector self findFirstResponder       to  nil  from  nil  forEvent  nil          return currentFirstResponder            func findFirstResponder sender  AnyObject            currentFirstResponder   self

User · Answer

The solution from romeo https   stackoverflow com a 2799675 661022 is cool  but I noticed that the code needs one more loop  I was working with tableViewController  I edited the script and then I checked  Everything worked perfect   I recommed to try this   -  void findFirstResponder       NSArray  subviews    self tableView subviews       for  id subv in subviews                 for  id cell in  subv subviews                  if   cell isKindOfClass  UITableViewCell class                                  UITableViewCell  aCell   cell                  NSArray  cellContentViews     aCell contentView  subviews                   for  id textField in cellContentViews                                        if   textField isKindOfClass  UITextField class                                                  UITextField  theTextField   textField                          if   theTextField isFirstResponder                                 NSLog   current textField       theTextField                               NSLog   current textFields s superview        theTextField superview

User · Answer

Using Swift and with a specific UIView object this might help  func findFirstResponder inView view  UIView  - gt  UIView        for subView in view subviews as   UIView            if subView isFirstResponder                 return subView                            if let recursiveSubView   self findFirstResponder inView  subView                return recursiveSubView                          return nil    Just place it in your UIViewController and use it like this  let firstResponder   self findFirstResponder inView  self view   Take note that the result is an Optional value so it will be nil in case no firstResponder was found in the given views subview hierarchy

User · Answer

This is what I have in my UIViewController Category   Useful for many things  including getting first responder  Blocks are great   -  UIView   enumerateAllSubviewsOf   UIView   aView UsingBlock   BOOL      UIView  aView    aBlock     for   UIView  aSubView in aView subviews       if  aBlock  aSubView         return aSubView      else if      aSubView isKindOfClass    UIControl class          UIView  result     self enumerateAllSubviewsOf  aSubView UsingBlock  aBlock        if  result    nil         return result                    return nil     -  UIView   enumerateAllSubviewsUsingBlock   BOOL      UIView  aView    aBlock    return   self enumerateAllSubviewsOf  self view UsingBlock  aBlock       -  UIView   findFirstResponder    return   self enumerateAllSubviewsUsingBlock  BOOL UIView  aView      if    aView isFirstResponder          return YES         return NO

User · Answer

you can call privite api like this  apple ignore    UIWindow  keyWindow     UIApplication sharedApplication  keyWindow   SEL sel   NSSelectorFromString   firstResponder    UIView    firstResponder    keyWindow performSelector sel

User · Answer

Code below work   -  id ht findFirstResponder         ignore hit test fail view     if  self userInteractionEnabled    NO    self alpha  lt   0 01    self hidden    YES            return nil            if   self isKindOfClass  UIControl class    amp  amp    UIControl   self isEnabled     NO            return nil               ignore bound out screen     if  CGRectIntersectsRect self frame   UIApplication sharedApplication  keyWindow bounds     NO            return nil             if   self isFirstResponder             return self             for  UIView  subView in self subviews            id result    subView ht findFirstResponder           if  result                return result                      return nil

[objective-c] Get the current first responder without using a private API

Swift 4

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