Remove all constraints affecting a UIView

Question

I have a UIView which is placed on the screen via several constraints  Some of the constraints are owned by the superview  others are owned by other ancestors  e g  perhaps the view property of a UIViewController    I want to remove all of these old constraints  and place it somewhere new using new constraints   How can I do this without creating an IBOutlet for every single constraint and having to remember which view owns said constraint   To elaborate  the naive approach would be to create a bunch of IBOutlets for each of the constraints  and would then involve calling code such as    viewA removeConstraint self myViewsLeftConstraint    viewB removeConstraint self myViewsTopConstraint    viewB removeConstraint self myViewsBottomConstraint    self view removeConstraint self myViewsRightConstraint     The problem with this code is that even in the simplest case  I would need to create 2 IBOutlets  For complex layouts  this could easily reach 4 or 8 required IBOutlets  Furthermore  I would need to ensure that my call to remove the constraint is being called on the proper view  For example  imagine that myViewsLeftConstraint is owned by viewA  If I were to accidentally call  self view removeConstraint self myViewsLeftConstraint   nothing would happen   Note  The method constraintsAffectingLayoutForAxis looks promising  but is intended for debugging purposes only     Update  Many of the answers I am receiving deal with self constraints  self superview constraints  or some variant of those  These solutions won t work since those methods return only the constraints owned by the view  not the ones affecting the view   To clarify the problem with these solutions  consider this view hierarchy    Grandfather   Father   Me   Son Daughter  Brother  Uncle    Now imagine we create the following constraints  and always attach them to their nearest common ancestor    C0  Me  same top as Son  owned by Me  C1  Me  width   100  owned by Me  C2  Me  same height as Brother  owned by Father  C3  Me  same top as Uncle  owned by Grandfather  C4  Me  same left as Grandfather  owned by Grandfather  C5  Brother  same left as Father  owned by Father  C6  Uncle  same left as Grandfather  owned by Grandfather  C7  Son  same left as Daughter  owned by Me    Now imagine we want to remove all constraints affecting Me  Any proper solution should remove  C0 C1 C2 C3 C4  and nothing else   If I use self constraints  where self is Me   I will get  C0 C1 C7   since those are the only constraints owned by Me  Obviously it wouldn t be enough to remove this since it is missing  C2 C3 C4   Furthermore  it is removing C7 unnecessarily   If I use self superview constraints  where self is Me   I will get  C2 C5   since those are the constraints owned by Father  Obviously we cannot remove all these since C5 is completely unrelated to Me   If I use grandfather constraints  I will get  C3 C4 C6   Again  we cannot remove all of these since C6 should remain intact   The brute force approach is to loop over each of the view s ancestors  including itself   and seeing if firstItem or secondItem are the view itself  if so  remove that constraint  This will lead to a correct solution  returning  C0 C1 C2 C3 C4   and only those constraints   However  I m hoping there is a more elegant solution than having to loop through the entire list of ancestors

User · Answer

You could use something like this    viewA superview constraints enumerateObjectsUsingBlock   id obj  NSUInteger idx  BOOL  stop        NSLayoutConstraint  constraint    NSLayoutConstraint   obj      if  constraint firstItem    viewA    constraint secondItem    viewA             viewA superview removeConstraint constraint               viewA removeConstraints viewA constraints     Basically  this is enumerates over all the constraints on the superview of viewA and removes all of the constraints that are related to viewA   Then  the second part removes the constraints from viewA using the array of viewA s constraints

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Based on previous answers  swift 4   You can use immediateConstraints when you don t want to crawl entire hierarchies    extension UIView          Deactivates immediate constraints that target this view  self   superview      func deactivateImmediateConstraints        NSLayoutConstraint deactivate self immediateConstraints           Deactivates all constrains that target this view     func deactiveAllConstraints        NSLayoutConstraint deactivate self allConstraints           Gets self constraints   superview  constraints for this particular view     var immediateConstraints  NSLayoutConstraint       let constraints   self superview  constraints filter           0 firstItem as  UIView     self     0 secondItem as  UIView     self                     return self constraints   constraints          Crawls up superview hierarchy and gets all constraints that affect this view     var allConstraints  NSLayoutConstraint        var view  UIView    self     var constraints  NSLayoutConstraint           while let currentView   view           constraints    currentView constraints filter               return  0 firstItem as  UIView     self     0 secondItem as  UIView     self                   view   view  superview           return constraints

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The only solution I have found so far is to remove the view from its superview    view removeFromSuperview    This looks like it removes all constraints affecting its layout and is ready to be added to a superview and have new constraints attached  However  it will incorrectly remove any subviews from the hierarchy as well  and get rid of  C7  incorrectly

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Details   Xcode 10 2 1  10E1001   Swift 5   Solution  import UIKit  extension UIView        func removeConstraints     removeConstraints constraints        func deactivateAllConstraints     NSLayoutConstraint deactivate getAllConstraints          func getAllSubviews   - gt   UIView    return UIView getAllSubviews view  self         func getAllConstraints   - gt   NSLayoutConstraint            var subviewsConstraints   getAllSubviews   flatMap    0 constraints           if let superview   self superview               subviewsConstraints    superview constraints compactMap    constraint  - gt  NSLayoutConstraint  in                 if let view   constraint firstItem as  UIView  view    self   return constraint                   return nil                                 return subviewsConstraints   constraints            class func getAllSubviews view  UIView  - gt   UIView            return view subviews flatMap     0    getAllSubviews view   0              Usage  print  constraints    view getAllConstraints   count   subviews    view getAllSubviews   count    view deactivateAllConstraints

User · Answer

This is the way to disable all constraints from a specific view   NSLayoutConstraint deactivate myView constraints

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As of July 31  2017   SWIFT 3  self yourCustomView removeFromSuperview   self yourCustomViewParentView addSubview self yourCustomView    Objective C   self yourCustomView removeFromSuperview    self yourCustomViewParentView addSubview self yourCustomView     This is the easiest way to quickly remove all constraints that exist on a UIView  Just be sure to add the UIView back with it s new constraints or new frame afterwards

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Swift Following UIView Extension will remove all Edge constraints of a view  extension UIView       func removeAllConstraints             if let  superview   self superview               self removeFromSuperview                superview addSubview self

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There are two ways of on how to achieve that according to Apple Developer Documentation  1  NSLayoutConstraint deactivateConstraints     This is a convenience method that provides an easy way to deactivate a   set of constraints with one call  The effect of this method is the   same as setting the isActive property of each constraint to false    Typically  using this method is more efficient than deactivating each   constraint individually       Declaration class func deactivate   constraints   NSLayoutConstraint       Usage NSLayoutConstraint deactivate yourView constraints    2  UIView removeConstraints  Deprecated for    iOS 8 0      When developing for iOS 8 0 or later  use the NSLayoutConstraint   class   s deactivateConstraints  method instead of calling the   removeConstraints  method directly  The deactivateConstraints  method   automatically removes the constraints from the correct views       Declaration func removeConstraints   constraints   NSLayoutConstraint        Usage yourView removeConstraints yourView constraints    Tips  Using Storyboards or XIBs can be such a pain at configuring the constraints as mentioned on your scenario  you have to create IBOutlets for each ones you want to remove  Even so  most of the time Interface Builder creates more trouble than it solves   Therefore when having very dynamic content and different states of the view  I would suggest    Creating your views programmatically  Layout them and using NSLayoutAnchor Append each constraint that might get removed later to an array Clear them every time before applying the new state   Simple Code  private var customConstraints    NSLayoutConstraint     private func activate constraints   NSLayoutConstraint         customConstraints append contentsOf  constraints      customConstraints forEach    0 isActive   true      private func clearConstraints         customConstraints forEach    0 isActive   false       customConstraints removeAll      private func updateViewState         clearConstraints        let constraints             view leadingAnchor constraint equalTo  parentView leadingAnchor           view trailingAnchor constraint equalTo  parentView trailingAnchor           view topAnchor constraint equalTo  parentView topAnchor           view bottomAnchor constraint equalTo  parentView bottomAnchor             activate constraints  constraints       view layoutIfNeeded       References   NSLayoutConstraint UIView

User · Answer

I use the following method to remove all constraints from a view    h file      void RemoveContraintsFromView  UIView  view      removeParentConstraints  bool parent      removeChildConstraints  bool child     m file      void RemoveContraintsFromView  UIView   view      removeParentConstraints  bool parent      removeChildConstraints  bool child       if  parent               Remove constraints between view and its parent          UIView  superview   view superview           view removeFromSuperview            superview addSubview view              if  child               Remove constraints between view and its children           view removeConstraints  view constraints              You can also read this post on my blog to better understand how it works behind the hood   If you need more granular control  I d strongly advise switching to Masonry  a powerful framework class you could use whenever you need to properly handle constraints programmatically

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You can remove all constraints in a view by doing this   self removeConstraints self constraints    EDIT  To remove the constraints of all subviews  use the following extension in Swift   extension UIView       func clearConstraints             for subview in self subviews               subview clearConstraints                     self removeConstraints self constraints

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Using a Reusable Sequence  I decided to approach this in a more  reusable  way   Since finding all constraints affecting a view is the basis for all of the above  I decided to implement a custom sequence that returns them all for me  along with the owning views   First thing to do is define an extension on Arrays of NSLayoutConstraint that returns all elements affecting a specific view   public extension Array where Element    NSLayoutConstraint        func affectingView   targetView UIView  - gt   NSLayoutConstraint             return self filter               if let firstView    0 firstItem as  UIView                  firstView    targetView                   return true                            if let secondView    0 secondItem as  UIView                  secondView    targetView                   return true                            return false                     We then use that extension in a custom sequence that returns all constraints affecting that view  along with the views that actually own them  which can be anywhere up the view hierarchy   public struct AllConstraintsSequence   Sequence        public init view UIView           self view   view            public let view UIView      public func makeIterator   - gt  Iterator           return Iterator view view             public struct Iterator   IteratorProtocol            public typealias Element    constraint NSLayoutConstraint  owningView UIView           init view UIView               targetView    view             currentView   view             currentViewConstraintsAffectingTargetView   currentView constraints affectingView targetView                     private let targetView    UIView         private var currentView   UIView         private var currentViewConstraintsAffectingTargetView  NSLayoutConstraint               private var nextConstraintIndex   0          mutating public func next   - gt  Element                 while true                    if nextConstraintIndex  lt  currentViewConstraintsAffectingTargetView count                       defer nextConstraintIndex    1                      return  currentViewConstraintsAffectingTargetView nextConstraintIndex   currentView                                     nextConstraintIndex   0                  guard let superview   currentView superview else   return nil                    self currentView   superview                 self currentViewConstraintsAffectingTargetView   currentView constraints affectingView targetView                                    Finally we declare an extension on UIView to expose all the constraints affecting it in a simple property that you can access with a simple for-each syntax   extension UIView        var constraintsAffectingView AllConstraintsSequence           return AllConstraintsSequence view self            Now we can iterate all constraints affecting a view and do what we want with them     List their identifiers     for  constraint     in someView constraintsAffectingView      print constraint identifier     No identifier       Deactivate them     for  constraint     in someView constraintsAffectingView      constraint isActive   false     Or remove them entirely     for  constraint  owningView  in someView constraintsAffectingView      owningView removeConstraints  constraint       Enjoy

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In Swift   import UIKit  extension UIView                 Removes all constrains for this view             func removeConstraints              let constraints   self superview  constraints filter               0 firstItem as  UIView    self     0 secondItem as  UIView    self                          self superview  removeConstraints constraints          self removeConstraints self constraints

User · Answer

A Swift solution   extension UIView     func removeAllConstraints         var view  UIView    self     while let currentView   view         currentView removeConstraints currentView constraints filter           return  0 firstItem as  UIView    self     0 secondItem as  UIView    self                view   view  superview               It s important to go through all the parents  since the constraints between two elements are holds by the common ancestors  so just clearing the superview as detailed in this answer is not good enough  and you might end up having bad surprise later on

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This approach worked for me   interface UIView  RemoveConstraints   -  void removeAllConstraints    end    implementation UIView  RemoveConstraints   -  void removeAllConstraints       UIView  superview   self superview      while  superview    nil            for  NSLayoutConstraint  c in superview constraints                if  c firstItem    self    c secondItem    self                     superview removeConstraint c                                   superview   superview superview              self removeConstraints self constraints       self translatesAutoresizingMaskIntoConstraints   YES      end  After it s done executing your view remains where it was because it creates autoresizing constraints   When I don t do this the view usually disappears   Additionally  it doesn t just remove constraints from superview but traversing all the way up as there may be constraints affecting it in ancestor views   Swift 4 Version extension UIView            public func removeAllConstraints             var  superview   self superview                  while let superview    superview               for constraint in superview constraints                                    if let first   constraint firstItem as  UIView  first    self                       superview removeConstraint constraint                                                     if let second   constraint secondItem as  UIView  second    self                       superview removeConstraint constraint                                                            superview   superview superview                            self removeConstraints self constraints          self translatesAutoresizingMaskIntoConstraints   true

User · Answer

The easier and efficient approach is to remove the view from superView and re add as subview again  this causes all the subview constraints get removed automagically

User · Answer

With objectiveC   self superview constraints enumerateObjectsUsingBlock     kindof NSLayoutConstraint    Nonnull obj  NSUInteger idx  BOOL    Nonnull stop            NSLayoutConstraint  constraint    NSLayoutConstraint   obj          if  constraint firstItem    self    constraint secondItem    self                 self superview removeConstraint constraint                          self removeConstraints self constraints

[ios] Remove all constraints affecting a UIView

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