Adding Constraint to a ScrollView - xcode

I have a scrollView that I have stretched the full width of the iOS application in Xcode. I'm using Xcode 6 and size classes so the width is set to 600X600 in the view panel. when I go to add a the constraints in IB, it shows 0 for the top, -16 for the left and right and 0 for the bottom. My question is why does it show -16? It appears as though all sides should display 0. I'm just trying to get a better understanding on how constraints work when using the new size classes.

Did you note the "Constraint to margins" checkbox? Thats what playing tricks with you I think.

Related

How to fix scrollable content size ambiguity in xcode 11 using auto layout beta 7 UIKIT

When using Auto Layout, I am unable to set up a simple UIScrollView in my view controller in Xcode 11 beta 7. I know that I must constrain the scroll view to the edges, and then set the scroll view width and height equal to the width and height of the entire view that contains the scroll view. However, I am not getting the option to set equal widths and heights when I attempt to do so.
When I do the right-click-drag from the scroll view to the entire main view, I get the following options:
Leading Space to Safe Area
Top Space to Safe Area
Trailing Space to Safe Area
Bottom Space to Safe Area
Center Horizontally in Safe Area
Center Vertically in Safe Area
In other videos, there is an "Equal Widths" and "Equal Heights" option that I don't seem to have.
Am I doing something wrong, or did Apple change the way scroll views work in Xcode 11?
I'm using beta 7 currently
I was finally able to successfully add a UIScrollView using storyboards in Xcode Version 11.0 (11A420a) after much trial and error.
You can add the scroll view directly to the root UIView of the VC or, if you needed to, add it to another UIView under the root view as needed by your UI Design. Constrain the UIScrollView parents normally for whatever your needs are.
Here is the key : when you add the UIScrollView to the storyboard, click on the Size Inspector with the UIScrollView selected. You have to UNCHECK the box that says "Content Layout Guides".
If you do this you can set the scroll view's contraints normally (I did 0-0-0-0 to superview). Then I added a UIView to the scrollview and set it's constraints to 0-0-0-0 and a height of 900 (which is what I wanted).
This will give you constraint errors in red when you set them. They will be fixed by setting the width of the UIView equal to the width of the UIScrollView.
Set the UIView width equal to the width of the UIScrollView view by Ctrl-right clicking on the UIView, dragging to the UIScrollView, and selecting the "Equal Widths" option. This should get rid of your constraint errors.
You actually can then go back to the UISCrollView Size Inspector and check the "Content Layout Guides" checkbox, no constraint errors will appear.
Disable the content layout guides in scrollview properties.
Hope it helps.. :)

How to fix "Scrollable Content Size Ambiguity" in Xcode 11 (iOS 12, iOS 13) using Auto Layout

When using Auto Layout, I am unable to set up a simple UIScrollView in my view controller in Xcode 11 beta. I know that I must constrain the scroll view to the edges, and then set the scroll view width and height equal to the width and height of the entire view that contains the scroll view. However, I am not getting the option to set equal widths and heights when I attempt to do so.
When I do the right-click-drag from the scroll view to the entire main view, I get the following options:
Leading Space to Safe Area
Top Space to Safe Area
Trailing Space to Safe Area
Bottom Space to Safe Area
Center Horizontally in Safe Area
Center Vertically in Safe Area
In other videos, there is an "Equal Widths" and "Equal Heights" option that I don't seem to have.
Am I doing something wrong, or did Apple change the way scroll views work in Xcode 11?
Disabling the content layout guides in the size inspector (ruler icon) in properties
I was having the same issue, and by disabling the option it was gone.
I stacked with that problem as well.
Found a good guide that helped me:
https://useyourloaf.com/blog/scroll-view-layouts-with-interface-builder/
Basically what you need is 9 constraints (assuming you want to scroll only vertically):
1-4: ScrollView to Superview (top, bottom, leading, trailing). Make sure to connect it to parent view and not to safe area.
5-8: Content view to Content Layout guide (top, bottom, leading, trailing).
Content view Width equals width to Frame Layout Guide.
I also encountered this problem (Version 11.0 beta 3 (11M362v)). I solved this problem by first setting the layout in xcode10 and then running it in xcode11. I haven't found any official instructions yet, proving that this is a problem with xcode11, but for now, I guess this is a problem with xcode11 bate.
After spending a long time on this scrolling issue in Xcode-11. The conclusion on this issue is you have to choose the scrolling option while adding a new constraint.
You can refer to the following screenshot to resolve your issue.
These mentioned solutions worked for me.
Disabling the content layout guides in properties worked for me.
Well, I was facing this issue but I have found a solution.
Problem is the Safe Area.
Embed Scroll view in a UIview.
give Top, Bottom, Right and Left 0.
now give constraints of scroll view with this view.
Add Equal height and width of content view to this View.
parent view is automatically giving Safe Area. All you have to do is just embed your scroll view in a UIview and then give equal height and equal width of the content view to this view.
#Vadim's answer worked with a little adjustment.
Nothing else worked and I didn't want to disable 'Content layout guide'. Since apple enabled it, why disable it. So there must be something I'm missing or it's a bug.
Vadim's answer is:
I stacked with that problem as well. Found a good guide that helped me:
https://useyourloaf.com/blog/scroll-view-layouts-with-interface-builder/
Basically what you need is 9 constraints (assuming you want to scroll only vertically):
1-4: ScrollView to Superview (top, bottom, leading, trailing). Make sure to connect it to parent view and not to safe area.
5-8: Content view to Content Layout guide (top, bottom, leading, trailing)
9: Content view Width equals width to Frame Layout Guide.
All good, but it didn't work,
But then I realize that the above 6 and 8 (trailing and bottom constraints to 'Content Layout guide') constraints are a little weird. They had positive constant values instead of zero. Like the below image. (constant equals to width and height of the scroll view). I changed them to zero and now it all works.
For me, initially the Content Layout Guides is in disabled state by default in ScrollView. So I just enabled and disabled the Content Layout Guides then the error disappeared automatically.
Xcode 11+, Swift 5.
I solved my issue, I prepared video and code

Xcode 8.3.3 autolayout - view is disappearing runtime when setting constraints

I'm trying to make a divider, so what I do is:
1) Make a new View
2) Change the background to the color I want the divider to be
3) Control click and center it horizontally on a label on top of it
4) Compile, my view is gone.
5) Remove constraints, compile, my view is there.
6) Add left and right constraint for autosize, compile, view is gone.
It also states that the height of my view is ambiguous.
How can the view be gone by merely constraining it?
Screenshot:
Your view does not disappear. It just getting zero size.
When you remove constraints it won't iOS won't layout your view that is why it's size not changing.
And in you last case with leading/trailing constrains your view will calculate its width depending on it's superview width, but since system can't calculate height it gonna change it to zero.
Other views and like labels and images have content and with a help of defined intrinsic content size they system won't resize them to zero sizes but to their content size.
here is my output I tried in swift using Xcode and tried setting constraints as I do

Xcode constraints Stack Views

I am trying to add constraints for the following to enable the buttons and label to adapt their size and font size to different screen sizes however everything I have tried so far has not worked, even when using Stack Views.
Could anyone help with this?
Storyboard Screenshot
My "breakthrough" in understanding and enjoying constraints was when I learned how to use the Constant and Multiplier attributes.
The four buttons appear to be about 80% of the width of the device. So, you could make a constraint between a button and the view and select "Equal Widths". Then, select the constraint and look at the Attributes Inspector. Change the Multiplier to 0.8 or whatever value you like. You will still need to set other constraints, such as center horizontally in container.
You could something similar with the horizontal buttons.
As for the text in the buttons, I needed this, too, and finally found the following (Objective-C):
button.titleLabel.adjustsFontSizeToFitWidth = YES;

Overflow-Y scroll not working

I got the constraints just how I want it in iPhone 5 it fits in one screen and in iPhone 4 it overflows to the bottom which is fine. But why can't I scroll down?
iPhone 5:
iPhone 4:
As you can see in iPhone 4 the bottom is not visible and all I want is to be able to scroll there.
Even without seeing how you are settings the constraints on the Interface Builder, I think that doing like below could help you to solve your problems:
Possibly you are not embeding all views in a scrollView properly. If so, select all subviews, choose Editor from menu -> Embed In -> View to wrap everything in a container. (UIView). After that select the container then choose Editor -> Embed in -> Scroll view
Set up all necessary constraints between subviews and the container ( As you did before making the view in the shared screenshot)
Set up all margins between the container and the containing scrollView to be zero ( top/ left/ right/ bottom = 0). Ensure that the scrollView fit the screen by having zero margin constraints as well.
Last but not least, set a width constraint of the container to any number you want (e.g.: 320 /375), then make an IBOutlet for this constraint
On viewDidLoad, set the constant of the container's width constraint you made in step 4 to current screen width.
That's all.

Resources