I have an UIImageView in storyboard that has no image set. I don't want the width to be set at design time, but rather have the image assigned to it at runtime drive the intrinsic content size but storyboard gives me a constraint error on missing constraint. What should I do to get rid of that?
Add a width constraint to the UIImageView and then in the Size inspector, click the box next to Placeholder Remove at build time:
This Placeholder constraint will satisfy Interface Builder, but it will be removed at build time and not get in the way at runtime.
Related
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.. :)
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
I create a XIB in Xcode and add a simple view as a subview:
What I want to achieve is that the subview has a fixed size and the rootview automatically resizes to the size of that subview, leaving a margin of 20.0 around it:
So I add a fixed width and a fixed height constraint to the subview. Then I add the four constraints for the 20.0 margin:
As the superview does not have any constraints there should be neither ambiguity nor conflicting constraints: I would expect the superview to shrink down in order to match the constraints. However, Xcode complains:
These constraints would only be conflicting if the rootview had a fixed size and that appears to be the case. So my question is: How can I make the rootview of a XIB flexible so that it dynamically adjusts its size to match its contents?
(Is that even possible with Interface Builder?)
How can I make the rootview of a XIB flexible so that it dynamically
adjusts its size to match its contents?
Not possible Interface builder.
As the superview does not have any constraints there should be neither
ambiguity nor conflicting constraints
Its not just a super view. Its also an objet in nib. We define simulated size for such views. This could be used to silence the errors. But again these are just simulated.
Is this rootView a view controllers view ? If yes i don't understand why are you trying to fix its withd to 280 and height to 168.
If this view is a custom view that you are going to add to another 'parent' view. Then you should change you simulated size to with 280 and height 168, and when adding this as subview you need to add two more constraints to position this rootview in the 'parent' view.
I had a same issue. I have a view in xib, which had dynamic content and it needed to fit into other superviews. so here is the answer how I achieved that
First you need to
myViewFromXib.translatesAutoresizingMaskIntoConstraints = false to prevent translating autoresizing mask into constraints. Then add subview superViewForMyViewFromXib.addSubview(myViewFromXib). And just add your constraints to superview like this:
NSLayoutConstraint.activate([
(myViewFromXib.topAnchor.constraint(equalTo: superViewForMyViewFromXib.topAnchor, constant: 0))!,
(myViewFromXib.bottomAnchor.constraint(equalTo: superViewForMyViewFromXib.bottomAnchor, constant: 0))!,
(myViewFromXib.leadingAnchor.constraint(equalTo: superViewForMyViewFromXib.leadingAnchor, constant: 0))!,
(myViewFromXib.trailingAnchor.constraint(equalTo: superViewForMyViewFromXib.trailingAnchor, constant: 0))!
])
superViewForMyViewFromXib.setNeedsLayout()
You can do this by editing the xib manually, for example to set a height constraint (in my case it was an inequality to set the minimum height):
add a constraint to a subview for the height
open the xib as a text file
find the constraint you added (eg by Cmd-F'ing to the value of the height)
cut and paste it into the root view's constraint section
Open the xib in interface builder again
The constraint appears and you can edit it like normal.
OMG, I cant believe you accept that this is not possible and change your way , if this was not possible then Xib would be useless. please don't provide wrong info to others your question is well detail but answer is more than poor:
answer is more than easy :
subview.frame.size.height = rootView.frame.size.height
subview.frame.size.width = rootView.frame.size.width
When UIImageView is empty...than resize the UILabel and hidden the UIImageView.
Anyone a idea?
You can either change label bottom constraint constant to either bottom spacing or image view top constraint - depending of visibility of image view or
(Available in iOS 8.0 and later.)
Create two bottom NSLayoutConstraint for label. One with lower priority to bottom of the view and one with higher priority. Change active property to YES/NO of the one with higher priority depending of image view visibility
I'm having trouble getting a UIScrollView to respect the constraints I put in interface builder.
All I need to be able to do is set the content size of the scroll view from within IB.
The UIScrollView contains a single UIView.
Constraints on the UIScrollView:
Constraints on the UIView:
I've read through the documentation, and so have set things up as follows:
the UIScrollView has constraints pinning it to its superview, thus defining its size from outside
the UIView (content) has a fixed size (through width and height constraints)
the UIView is pinned to the UIScrollView, thus defining the content size
However, IB won't let me enter these constraints. If I change the 'Bottom Space' constraint between the view and the scroll view, shown in the image as -2196, to 0 (thus pinning the lower edge of the scroll view), then the 'Top Space' constraint resets to a non-zero value. The same happens in reverse. (I haven't yet tried in Xcode 5, which has a far saner approach to invalid constraints in that it doesn't just throw yours away when it feels like it.)
What am I missing?
Every time I've tried to do something even mildly sophisticated with constraints in Xcode 4's Interface Builder, I've eventually given up and either written the constraints in code or switched back to springs'n'struts and layoutSubviews (usually after crashing Xcode a few times).
That said, there is another approach to laying out a scroll view with content in IB. Just make the scroll view as big as its content size, and rely on the view controller (or some containing view controller) to resize the scroll view (or its superview) and let the constraints shrink down the scroll view's frame at runtime. The window's root view controller will always set its view's frame to the screen size, regardless of its size in the nib or storyboard, and that resizing flows down the view hierarchy.
I described this approach in more detail in this answer.
If your scroll view's content size is really supposed to be 2196 points tall, this probably won't work so well. I don't have anything better to suggest in that case.