UIScrollView Scrollable Content Size Ambiguity

Question

Fellow devs  I am having trouble with AutoLayout in Interface Builder  Xcode 5   iOS 7   It s very basic and important so I think everyone should know how this properly works  If this is a bug in Xcode  it is a critical one   So  whenever I have a view hierarchy such as this I run into trouble    gt UIViewController  gt  gt  UIView  gt  gt  gt UIScrollView  gt  gt  gt  gt UILabel  or any other comparable UIKit Element    The UIScrollView has solid constraints  e g   50 px from every side  no problem   Then I add a Top Space constraint to the UILabel  no problem   and I can even pin height   width of the label  changes nothing  but should be unneccessary due to the Label s intrinsic size   The trouble starts when I add a trailing constraint to the UILabel   E g   Trailing Space to  Superview Equals  25  Now two warnings occur - and I don t understand why   A  Scrollable Content Size Ambiguity  Scroll View has ambiguous scrollable content height width   B  Misplaced Views  Label Expected  x  -67 Actual  x  207  I did this minimal example in a freshly new project which you can download and I attached a screenshot  As you can see  Interface Builder expects the Label to sit outside of the UIScrollView s boundary  the orange dashed rectangle   Updating the Label s frame with the Resolve Issues Tool moves it right there   Please note  If you replace the UIScrollView with a UIView  the behaviour is as expected  the Label s frame is correct and according to the constraint   So there seems to either be an issue with UIScrollView or I am missing out on something important   When I run the App without updating the Label s frame as suggested by IB it is positioned just fine  exactly where it s supposed to be and the UIScrollView is scrollable  If I DO update the frame the Label is out of sight and the UIScrollView does not scroll   Help me Obi-Wan Kenobi  Why the ambiguous layout  Why the misplaced view   You can download the sample project here and try if you can figure out what s going on  https   github com Wirsing84 AutoLayoutProblem

User · Answer

If anyone is getting a behavior where you notice the scroll bar on the right scrolls but the content doesn't move, this fact probably worth considering:

You can also use constraints between the scroll view’s content and objects outside the scroll view to provide a fixed position for the scroll view’s content, making that content appear to float over the scroll view.

That's from Apple's documentation. For example , if you accidentally pinned your top Label/Button/Img/View to the view outside the scroll area (Maybe a header or something just above the scrollView?) instead of the contentView, you'd freeze your whole contentView in place.

User · Answer

all the subviews inside a scrollview must have constraints touching all the edges of the scroll view  as its explained in the documentation  the height and width of a scroll view is calculated automatically by the measures in of the subviews  this means you need to have Trailing and leading constraints for width and Top and Bottom constraints for height

User · Answer

Using Autolayout  Add your scroll view inside a well defined view and then add the stack view inside the scroll view  Add top  left  right  bottom  center X and center Y constraints from scroll view and stack view to their relevant super views  Make sure that constraints are linked from stack view to the rightful superview  scrollview  since current default setting is to add an Align Top constraint and not a Top Space one

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Swift 4  approach   1  Set UIScrollView top  bottom  left and right margins to 0  2  Inside the UIScrollView add a UIView and set top  bottom  leading  trailing margins to 0   equal to UIScrollView margins      3  The most important part is to set width and height  where height constraint should have a low priority   private func setupConstraints             Constraints for scrollView     scrollView topAnchor constraint equalTo  view topAnchor  isActive   true     scrollView leadingAnchor constraint equalTo  view leadingAnchor  isActive   true     scrollView trailingAnchor constraint equalTo  view trailingAnchor  isActive   true     scrollView bottomAnchor constraint equalTo  view bottomAnchor  isActive   true         Constraints for containerView     containerView topAnchor constraint equalTo  scrollView topAnchor  isActive   true     containerView bottomAnchor constraint equalTo  scrollView bottomAnchor  isActive   true     containerView leadingAnchor constraint equalTo  scrollView leadingAnchor  isActive   true     containerView trailingAnchor constraint equalTo  scrollView trailingAnchor  isActive   true     containerView widthAnchor constraint equalTo  scrollView widthAnchor  isActive   true      let heightConstraint   containerView heightAnchor constraint equalTo  scrollView heightAnchor      heightConstraint priority   UILayoutPriority rawValue  250      heightConstraint isActive   true

User · Answer

It s answer for my self-answered question UIScrollView   Centered View   Ambigous Scrollable Content Size   many iPhone sizes   But it fully cover your case too   So  here is the initial state for simplest case    scrollView with 0 constraints to all edges Button centered Horizontal and Vertical with fixed Width and Height constraints And  of course - annoying warnings Has ambiguous scrollable content width and Has ambiguous scrollable content height      All  that we have to do is    Add 2 additional constraints  for example  0  for trailing and or bottom space for our view  look at the example on screenshot below     Important  you have to add trailing and or bottom constraints  Not  leading and top  - it s not works     You can check it in my example project  that demonstrating how to fix this issue   P S   According logic - this action should cause  conflicting constraints   But no   I don t know why it works and how Xcode detects which constraint is more prioritised  because I m not set priority for these constraints explicity   I ll be thankful if someone explain  why it works in comments below

User · Answer

So I just sorted out in this way    Inside the UIScrollView add a UIView  we can call that contentView   In this contentView  set top  bottom  left and right margins to 0  of course from the scrollView which is the superView   Set also align center horizontally and vertically    Finished   Now you can add all your views in that contentView  and the contentSize of the scrollView will be automatically resized according with the contentView   Update   Some special case is covered by this video posted by  Sergio in the comments below

User · Answer

Xcode 11   Swift 5  If you are wondering why all of the answers does not work anymore  make sure that you have pinned the content view  the one you ve put inside the scroll view  to Content Layout Guide of the scroll view and NOT to Frame Layout Guide   Content view edges  leading  trailing  top  bottom  should not be pinned like leading on the image - to Frame Layout Guide    but like this - to Content Layout Guide        And then the most of the answers will work for you   The most simple approach now is going like this    Put scroll view in the root view Pin all the sides of scroll view to the superview Take another UIView  will call it content view  and put it inside the scroll view Pin all the sides of the content view to scroll view s Content Layout Guide Pin the content view s width to be equal to scroll view s Frame Layout Guide Fix the content view height in any way you want  I used just constant height constraint in the example below    Overall your structure in the simplest implementation will look like this

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Using contentView  UView  as container inside UIScrollView  stick to edges  top  bottom  trailing  leading  of superview  UIScrollView  and contentView should have equalwidth and equalheight to superview  Those are constraints  And call of method   - void viewDidLayoutSubviews        super viewDidLayoutSubviews       self scrollView contentSize   self contentView frame size      Solved issues for me

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Set the ViewController s  the one holding the UIScrollView  size to Freeform in the size inspector in Interface Builder and all should work   Freeform setting in Size inspector in Interface Builder for the containing UIViewcontroller

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I made a video on youTube  Scroll StackViews using only Storyboard in Xcode  I think 2 kind of scenarios can appear here   The view inside the scrollView -   does not have any intrinsic content Size  e g UIView  does have its own intrinsic content Size  e g UIStackView    For a vertically scrollable view in both cases you need to add these constraints    4 constraints from top  left  bottom and right  Equal width to scrollview  to stop scrolling horizontally    You don t need any other constraints for views which have his own intrinsic content height      For views which do not have any intrinsic content height  you need to add a height constraint  The view will scroll only if the height constraint is more than the height of the scrollView

User · Answer

Check out this really quick and to the point tutorial on how to get the scroll view working and fully scrollable with auto layout  Now  the only thing that is still leaving me puzzled is why the scroll view content size is always larger then necessary    http   samwize com 2014 03 14 how-to-use-uiscrollview-with-autolayout

User · Answer

This error took me a while to track down  initially I tried pinning the ScrollView s size but the error message clearly says  content size    I made sure everything I pinned from the top of the ScrollView was also pinned to the bottom   That way the ScrollView can calculate its content height by finding the height of all the objects  amp  constraints   This solved the ambiguous content height  the width is pretty similar     Initially I had most things X centered in the ScrollView  but I had to also pin the objects to the side of the ScrollView   I don t like this because the iPhone6 might have a wider screen but it will remove the  ambiguous content width  error

User · Answer

I think it is a 10 second work from now  I observed it in XCode 7 3 and made a video on it  Check here   https   www youtube com watch v yETZKqdaPiI  All you have to do  add a subview to UIScrollView with same width and height  Then select ViewController and press Reset to suggested constraint  Please check video for clear understanding   Thanks

User · Answer

As mentioned in previous answers  you should add a custom view inside the scroll view     Add all your subviews to the content view  At some point you will see a scroll content view has ambiguous content size warning  you should select the content view and click the  Resolve auto layout issues  button  at the bottom right corner of the IB layout   and select the  Add missing constraints  option     From now on when you run the project  the scroll view will automatically update it s content size  no additional code needed

User · Answer

import UIKit  class ViewController  UIViewController               let scrollView  UIScrollView                      let sv   UIScrollView           sv translatesAutoresizingMaskIntoConstraints   false         return sv                  let lipsumLbl  UILabel        you can use here any of your subview                  let lbl   UILabel           lbl translatesAutoresizingMaskIntoConstraints   false         lbl text    quot  quot  quot          Lorem ipsum dolor sit amet  consectetur adipiscing elit  Fusce eleifend nisi sit amet mi aliquet  ut efficitur risus pellentesque  Phasellus nulla justo  scelerisque ut libero id  aliquet ullamcorper lectus  Integer id iaculis nibh  Duis feugiat mi vitae magna tincidunt  vitae consequat dui tempor  Donec blandit urna nec urna volutpat  sit amet sagittis massa fringilla  Pellentesque luctus erat nec dui luctus  sed maximus urna fermentum  Nullam purus nibh  cursus vel ex nec  pulvinar lobortis leo  Proin ac libero rhoncus  bibendum lorem sed  congue sapien  Donec commodo  est non mollis malesuada  nisi massa tempus ipsum  a varius quam lorem vitae nunc                   Cras scelerisque nisi dolor  in gravida ex ornare a  Interdum et malesuada fames ac ante ipsum primis in faucibus  Maecenas vitae nisl id erat sollicitudin accumsan sit amet viverra sapien  Etiam scelerisque vulputate ante  Donec magna nibh  pharetra sed pretium ac  feugiat sit amet mi  Vestibulum in ipsum vitae dui vehicula pulvinar eget ut lectus  Fusce sagittis a elit ac elementum  Fusce iaculis nunc odio  at fermentum dolor varius et  Suspendisse consectetur congue massa non gravida  Sed id elit vitae nulla aliquam euismod  Pellentesque accumsan risus dolor  eu cursus nibh semper id                   Vestibulum vel tortor tellus  Suspendisse potenti  Pellentesque id sapien eu augue placerat dictum  Fusce tempus ligula at diam lacinia congue in ut metus  Maecenas volutpat tellus in tellus maximus imperdiet  Integer dignissim condimentum lorem  id luctus nisi maximus at  Nulla pretium  est sit amet mollis eleifend  tellus nulla viverra dolor  ac feugiat massa risus a lectus  Pellentesque ut pulvinar urna  blandit gravida ipsum  Nullam volutpat arcu nec fringilla auctor  Integer egestas enim commodo  faucibus neque ac  rutrum magna  Vivamus tincidunt rutrum auctor  Cras at rutrum felis  Fusce elementum lorem ut pharetra venenatis           quot  quot  quot          lbl textColor    darkGray         lbl font   UIFont systemFont ofSize  16          lbl numberOfLines   0         return lbl                                                                                                           MARK - viewDidLoad            override func viewDidLoad             super viewDidLoad                    setupViews           setupAutoLayout                  func setupViews                      title    quot ScrollView Demo quot          view backgroundColor    white         view addSubview scrollView          scrollView addSubview lipsumLbl                 func setupAutoLayout                      scrollView leftAnchor constraint equalTo  view leftAnchor  isActive   true         scrollView rightAnchor constraint equalTo  view rightAnchor  isActive   true         scrollView topAnchor constraint equalTo  view topAnchor  isActive   true         scrollView bottomAnchor constraint equalTo  view bottomAnchor  isActive   true                  lipsumLbl topAnchor constraint equalTo  scrollView topAnchor  isActive   true         lipsumLbl leftAnchor constraint equalTo  view leftAnchor  isActive   true         lipsumLbl rightAnchor constraint equalTo  view rightAnchor  isActive   true         lipsumLbl bottomAnchor constraint equalTo  scrollView bottomAnchor  isActive   true          Output

User · Answer

Vertical Scrolling   Add a UIScrollView with constraints 0 0 0 0 to superview  Add a UIView in ScrollView  with constraints 0 0 0 0 to superview  Add same width constraint for UIView to UIScrollView  Add Height to UIView  Add elements with constraints to the UIView  For the element closest to the bottom  make sure it has a constraint to the bottom of UIView

User · Answer

tested in XCode 7 2 and for iOS 9 2   What suppressed the Storyboard errors and warnings for me was setting the intrinsic size of the scroll view and the content view  in my case  a stackview  to Placeholder  This setting is found in the Size inspector in Storyboard  And it says - Setting a design time intrinsic content size only affects a view while editing in Interface Builder  The view will not have this intrinsic content size at runtime   So  I guess we aren t going wrong by setting this    Note  In storyboard  I have pinned all the edges of scrollview to the superview and all the edges of stackview to the scrollview  In my code  I have set the translatesAutoresizingMaskIntoConstraints as false for both the scrollview and the stackview  And I have not mentioned a content size  When the stackview grows dynamically  the constraints set in storyboard ensure that the stack is scrollable    The storyboard warning was driving me mad and I didn t want to centre things horizontally or vertically just to suppress the warning

User · Answer

For any view  the frame and its content s sizes are the same ie if you have some content  e g  image  with the size of 200   800 then its frame is also 200   800  This is NOT true for scrollview s contents  The content is usually bigger than the frame size of the scrollView  If content is same in width  then you only scroll vertically  If it s same height then you only scroll horizontally  Hence it s the only view that needs 6 constraints not 4  For any other view having more than 4 required constraints will cause a conflict   To setup your scroll view  its contents and position of scrolling  you basically need to answer three questions   How big is my frame  ie at any given moment how big should the scrollview be  e g  I only want to use half of the screen s height so  scrollview frame    x  0  y 0  width  UIScreen main bounds width  height  UIScreen main bounds height   2    How much scrolling space do I need  ie How big is the content  e g  the frame can be just 500 points of width  but then you can set an image with 7000 points  which would take quite some time to scroll horizontally  Or let it be exactly 500 points of width which then means no horizontal scrolling can happen   How much have you scrolled at the moment  Say your content s  or image  width was 7000 and the frame size is just 500  To get to the end of the image  you d need to scroll 6500 points to the right  The 3rd part really doesn t affect the constraints  You can ignore that for now  Understanding it just helps how a scrollView works    Solution Basically if you leave out the 2 extra constraints  about the content size  then the layout engine will complain due to the ambiguity  It won t know what area of  the content is hidden  not visible in the scrollView  and what area of the content is not  visible in scrollView  hidden  So make sure you add size constraints for the content as well But some times I don t add size constraints to my views and it just works  Why is that  If all the contents you ve added into the scrollview are constrained to the edges of the scrollview  then as the content grow the scrollview will add space to accommodate  It s just that you might be using UIViews where its intrinsicContentSize is 0 so the scrollView will still complain about ambiguity of its content  However if you ve used a UILabel and it has a non-empty text  then its intrinsicContentSize is set  based on Font size and text length and line breaks  etc  so the scrollView won t complain about its ambiguity

User · Answer

See below  content view in scrollview vertical and horizontal centralized  you got ambiguity error  always make sure two added into scrollview from your content view is 1  button space to container 2 trailing space to constraint that is highlighted in screenshot     these constraint means in scroll is how much you can scroll after your content view height or width     it may help you

User · Answer

I know I may be late  but next solution solves this kind of problems without additional code  just using storyboards   For your content view you need to set constraints for leading trailing top bottom spaces to scrollview and this will not change content view frame  like this    Of course you need to create additional constraints for content view so scroll view could know content size  For example set fixed height and center x   Hope this helps

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You just have to make sure that there is a way to make a continuous   line of constraints from the top to the bottom of the scrollview     -X-X-X    In my case - a horizontally scrolling scroll view - I also needed to add width and height constraints for each child of the scroll view  although Apple s technical note doesn t tell you this

User · Answer

Xcode 11   Swift 5   According to  WantToKnow answer  I solved my issue  I prepared video and code

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I was getting the same error   i have done following   View Superview  ScrollView 0 0 600 600 UIView inside ScrollView   0 0 600 600 UIView contains image view   label   Now add leading trailing top bottom for scrollView 2  then UIView 3    Select View 1  and View 3  set equally height and weight   its solved my issue   I have done the video that will help    https   www youtube com watch v s-CPN3xZS1A

User · Answer

In my case I received the issue of incorrect content size and content Size Ambiguity in iPad but was working in case of iPhone  I have done the following changes in storyboard to resolve the issue    Add scrollview in UIView and add constraints leading  top  trailing and bottom to 0 0 0 0   Set height of scroll view as per the requirements for eg  100  Add UIView to scroll view and add constraints leading  top  trailing and bottom to 0 0 0 0 and align centre X  and center Y  constraints  Deselect    Content Layout Guides    in size inspector of scroll view

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If you still have problems with UIScrollView  just turn off Content Layout Guides  Select your ScrollView in xcode Interface Builder -  choose Size inspector in right panel -  deselect  Content Layout Guides   Or try these steps  xcode 11 scroll view layouts - it can  be useful for new style of layout  Works fine at macOS 10 15 2  Xcode 11 3 1  for 05 02 2020  see screenshot

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For me adding a contentView didn t really work as suggested  Moreover  it creates an overhead due to the added view  although I don t consider this a big problem   What worked best for me was just to turn off the ambiguity-checking for my scrollView  Everything is laying out nicely so I think it s okay in simple cases like mine  But keep in mind  that if other constraints for your scrollView break  the Interface-Builder will not warn you any more about it

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Xcode 11   The simplest way using autolayout    Add UIScrollView and pin it 0 0 0 0 to superview  or your desired size  Add UIView in ScrollView  pin it 0 0 0 0 to all 4 sides and center it horizontally and vertically  In size inspector  change bottom and align center Y priority to 250   for horizontal scroll change trailing and align center X  Add all views that you need into this view  Don t forget to set the bottom constraint on the lowest view  Select the UIScrollView  select the size inspector and deselect Content Layout Guides

User · Answer

I solved this kind of problem for my view by using  Resolve auto layout issues     Add missing constraints  for Selected View   The following two constraints solve my problem   trailing   Stack View trailing - 10 bottom   Stack View bottom   76   in which  trailing  bottom are the trailing  bottom of UIScrollView

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What I did is create a separate content view as shown here    The content view is freeform and can has all subviews added to it with their own constraints in relation to the contentView   The UIScrollView is added to the main view controller   Programatically I add the contentView which is linked via IBOutlet to class and set the contentView of UIScrollView

User · Answer

You need to create an UIView as a subview of the UIScrollView as described below    UIViewController UIView  Main View    UIScrollView   UIView  Container View     Your content       The second step is to make the UIScrollView constraints  I did this with the top  bottom  leading and trailing constraints to its superView   Next I added the constraints for the container of UIScrollView and here is where the problem begins  When you put the same constraints  top  bottom  leading and trailing  the Storyboard gives a warning message     Has ambiguous scrollable content width  and  Has ambiguous scrollable content height   Continue with the same constraints above  and just add the constraints Equal Height and Equal Width to your Container View in relation to the Main View and not to your UIScrollView  In other words the Container View s constraints are tied to the UIScrollView s superview   After that you will not have warnings in your Storyboard and you can continue adding the constraints for your subviews

User · Answer

People who are struggling with uiscrollview not scrolling just set your content view s bottom constraint with your last view s bottom layout  which is inside of your content view   Do not forget to remove center Y constraint    Rest all the constraints are same as defined above  Scrollview only concerned about getting maximum height from its content view  and we are setting it as last view s bottom constraint  which means scrollview automatically will change its content offset   In my case last view was UILable with no of lines property   0 which automatically adjust its height depending upon its content  so it dynamically increase uilable s height and eventually our scrollable area increases because of uilable s bottom layout is aligned with our content view s bottom  which forces scrollview to increase it s content offset

User · Answer

I had the same issue  Untick this checkbox  Since you are setting the content size in code

User · Answer

Matteo Gobbi s answer is perfect  but in my case   the scrollview can t scroll  i remove  align center Y  and add  height   1   the scrollview will became scrollable

User · Answer

I finally figured this out  I hope this is easier to understand    You can often bypass that warning by adding a base UIView to the scrollview as a  content view   as they mentioned and make it the same size as your scroll view and  on this content view  set these 6 parameters      As you can see  you need 6 total parameters  Which   under normal circumstances  you re duplicating 2 constraints but this is the way to avoid this storyboard error

[ios] UIScrollView Scrollable Content Size Ambiguity

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