I have three views I want to divide in a superview.
Currently, when I set proportional heights, I get weird results when updating the multiplier in those constraints.
As you can see, there is weird space between the top and the first proportional view and the second.
I want no room in between.
Who can help me out?
Two things immediately
It would be simpler to set the proportional height in this case between each of the views and their superview. This may not be what you want but either way my example below would work with slight tweaking
You only need to set two of the views to have proportional height. The third view (the one in the middle) can just take up the remaining space in between them.
See the Red, Green and Blue views -
The red view hugs the top, left and right and has a proportional
height
The green view hugs the bottom, left and right and has a proportional
height
The blue view hugs the left and right and has vertical spacing (zero)
to the red view and vertical spacing (zero) to the green view.
Related
In my app, i need to put some boxes and make sure first two of them divided equally.
Navigation bar + status bar holds 64 point.
Fixed height constraint of 60 point set to welcome box.
Fixed height constraint of 145 point set to brown box.
Tabbar holds 50 point.
Rest of the height which is 417 point should be divided into two.
Green and Red boxes has its scrollviews in themselves. Scrollviews has layout constraint of same height, top, bottom, leading and trailing constraint for that of its superview.
After layout is done, i inspected that red box has height of 208.66667 and green box has 208.3333.
But each scroll views have height of 208.6667. So the scroll view at green box becomes vertically scrollable because its height(contentSize height) is bigger than that of its superview.
You have some options.
Resize the content of the scroll views to be 208px and ignore the left-over partial pixel.
Disable scroll bars on the scroll views if you don't need them.
Add a pixel to one of the other areas so that the red and green views can be equal heights.
Size the views to the exact pixel dimension you want rather than just an "equal height" constraint.
In the above, the orange, blue and green views are subviews of the yellow view. I need the parent (yellow) view's borders to hug its subviews. The only movement that's occurred between the two images is the green subview moving up and to the right.
Because the bottom of the orange view is now lower than the bottom of the green view, the parent view hugs the orange view's bottom edge.
Similarly, because the green view's right edge is past the blue view's right edge, the parent view hugs the green view's right edge.
Is there a way to do this with Auto Layout constraints, or would I have to write custom code?
For the bottom edge, both the orange and green views require two vertical space constraints each. They are:
Vertical space constraint with relation set to "Greater Than or Equal" and constant set to 0.
Vertical space constraint with relation set to "Equal", constant set to 0 and a priority lower than the first constraint.
The first constraint ensures that no matter what, the space will be greater than or equal to zero. The second constraint says if possible, also have the space equal to exactly zero.
The above can then be replicated for the right edges of the blue and green views, using horizontal space constraints instead.
I have several UILabels laid out on my View Controller. While working in Portrait mode, I have increased the height of each label so that the boundaries are all touching - they're stacked on top of each other without any spacing in-between. I have a big title and button located at the top and bottom. I have already fixed the top title to always be centered at the top, and the bottom button fixed to the bottom. I also have fixed the middle label to be vertically and horizontally centered in the view. That's all working great. My problem is, I can't seem to figure out how to get the labels to all fit on screen and mostly vertical centered collectively when the height is reduced. I would like it to reduce the height of each label as needed (but not too short such that the text is clipped). I've tried pinning the heights and then changing them to less than or equal to, but in doing so it wants to update the frame to remove the extra height, causing the buttons to no longer be stacked right on top of each other. Then if I set vertical spacing constraints, it will be fixed so it will result in the labels too close together in Portrait if I use the standard value, or if I go with a fixed number they won't adjust to fit in Landscape.
What do I need to do in order to have the labels expanded to fill most of the view when in Portrait, shrink a bit on a 3.5" screen, then really shrink when in Landscape? The labels should all be centered collectively, based off that middle label that's always centered. This is basically what I'd like to obtain:
What you want to do is set the label's heights to be equal to one another. Then provide constraints for distances between each label, and between L/R sides and top/bottom sides. This way, the labels will shrink when the screen height shrinks.
I really wish I could get my head around auto layout. It seems that whenever I read an abstract description of how things are supposed to work it makes sense, but whenever I actually try and put it into practise it always causes massive headaches. So, apologies if there is already an answer out there for this but I couldn't find one.
The problem should be relatively simple. I have a container view, which contains two subviews, shown here in hideous colours for maximum readability :) :
The bottom (black) view, should remain at it's current size and maintain the spacing between it and the red view, and the spacing between itself and the bottom of yellow view.
The red view I want to be able to dynamically change its height, causing the black view to shift up/down accordingly whilst the yellow view resizes to fit both the red+black views.
For the black view, I've added constraints to:
Set the height to 94
Pin the leading and trailing space to superview
Set the top space to the red view at 51.
Set the bottom space to the yellow view at 20.
I am trying to understand what seemingly-mystical set of constraints I need to add in order that, when the red view is resized vertically, the black view stays its current distance from the red view and maintains its size, and the outer container view resizes accordingly so that it contains the red view + black view + vertical spacing between the views.
For the red view, I've added constraints to pin the top, left and right spacing to superview, but have had no luck working out the vertical constraints. Currently I've got a constraint pinning the height =114 with a priority of 999 and a constraint with height >=114 with a priority of 1000 thinking this would ensure the view is always at least 114 in height...
The fun starts when I try and manually set the height of the red view.... I've added a button on the view, and when the button is pressed, I manually set the bounds of the red view. (The red view's default height is 114):
CGRect bounds = self.redView.bounds;
bounds.size.height = 300;
self.redView.bounds = bounds;
When I run this and press the button, the view goes from this:
To this:
To me this makes no sense whatsoever. Why does this result in:
The Y origin of the red view changing? Particularly when there is a "required" constraint telling it to stay 20pts from the top of yellow view.
The spacing between the red and black views breaking down, even though the constraint on the spacing between them is "required"?
The vertical size of yellow view not changing. Again, despite the spacing between red+black, and me having tried just about every combination I can think of in terms of compression resistance and content hugging priority.....
I really want to understand this, so would be really grateful if someone can explain what additional constraints / changes to constants are required, but more importantly WHY they are required, because to me it doesn't seem clear at all how the layout system comes up with its answers....
Any clarification much appreciated.
Thanks in advance
(All code above is running on iOS 7 and built with Xcode 5.0.2).
You don't need any fancy constraints to do what you want here -- no inequalities or messing with the priorities. In addition to the constraints to the sides, the red view should have 20 to top, 51 to black view, and a height constraint of 114. The black view, has a 20 to the bottom and a height of 94. The superview (yellow) should have zero constraints to top, left and right -- no height. You should have an IBOutlet to the red view's height constraint. When you want to change its height, modify its constraint (don't set frames):
- (IBAction)resizeYellowView:(id)sender {
self.heightCon.constant = 300;
}
Everything is linked together from the top of the yellow view to the bottom with fixed values, so the only thing that can change when the height of the red view changes, is the height of the yellow view.
I have a UIViewController on my storyboard that has 2 subviews side-to-side horizontally. I added constraints to fix the leading and trailing edges to a constant (20 pts), and another constraint to keep the widths equal. If I assume the following, it should be possible to calculate what the width of each subview will need to be:
the subviews do not overlap
there are no other views present (horizontally, at least)
the width of the screen (the superview) is known
However, XCode gives me a warning that my views are horizontally ambiguous. I'm guessing that means that XCode is not making one of these assumptions, but which one is it? And is there a way for me to instruct XCode to make that assumption?
EDIT: Okay, played with it a bit and got the warning to go away, but it looks like it's not making the first assumption - it's just setting each subview's width to superview.width - 40, and happily burying one view underneath the other. So the question is how to I stop them from overlapping?
EDIT 2: Okay, my actual screen is a lot more complicated than my simple example. Here's what I got:
So in this setup I have 4 views that are vertically and horizontally staggered. I want the blue, red, and purple views to all be the same subview.frame.size.width = superview.width - 60. The blue and purple are lined up in the left column, and the red is alone in the right column, and all the gaps (between the two columns and between each column and it's nearest edge) are at a constant (20 pts). These 3 tables have a variable height, which I will be setting programmatically as described in James's answer here. At the bottom is a pink view that stretches the width of the screen (minus gaps), and sits at a constant 20 pts below either the purple or the red view, whichever is lower (which I'm attempting to do by giving it a spacing constraint of >= 20 to each view, and I hope that it will pick exactly 20 for one of them). Since all of the heights are dynamic and may not necessarily fit on the screen at the same time, I made their superview a UIScrollView instead of the normal UIView.
When all is said and done, I'm still getting a warning that all 4 of my views are horizontally ambiguous, and that the pink bar is vertically ambiguous. I think it's having trouble realizing what is supposed to go next to what, which is why it thinks it's horizontally ambiguous. And I think it's not picking to place the pink bar exactly 20 pts below either the purple or red views, which is why it thinks it's vertically ambiguous. Can anyone confirm or deny any of these suspicions? Or suggest a way around it? When I run it in the end, I just get this (I made the background of the scroll view yellow, which you can't tell in the storyboard screenshot):
Vertically Ambiguous
Okay, I think I've solved the vertical ambiguous part. I added two vertical constraints between the pink and purple views and two vertical constraints between the pink and red views. For each pair, the first constraint is that the spacing between them must be > 20 pts, and it has 1000 priority. The second constraint is that the spacing is = 20 pts, but it only has an 800 priority.
For example, if the bottom of the purple view ends up being lower than the bottom of the red view (as it is in my first screenshot), Xcode should try to set the vertical distance between the pink and red views = 20, but it will realize that that conflicts with condition that the space between the purple and pink being >= 20. Since the >= constraint has higher priority, the = constraint will be ignored. Now, when Xcode looks at the constraint that the spacing between the purple and pink views being = 20, it checks that against the constraint that the pink and red must be separated by at least 20. Since the bottom of the red view is higher than the bottom of the purple view, the >= 20 constraint between the red and the pink still passes.
So TL;DR, you can set up a view to have a spacing at a given value (x) from the most extreme of multiple views by giving it a >= x constraint with 1000 priority and giving it a = x constraint with <1000 priority for each view you are considering - and my vertical ambiguity problem has been solved. I do not yet have a solution for the horizontal ambiguity for all 4 of the views.
Horizontally Ambiguous
Okay, I got the horizontally ambiguous part fixed now as well. What it boils down to is that constraints in scroll views (and therefore table views) work differently than they do for any other kind of view. Here's what the step-by-step looks like.
Place the UIScrollView
Place a UIView into the UIScrollView to serve as a "contentView" for that scroll view
Add constraints to pin the contentView to all 4 corners of the scroll view AND pin it's width and height (so 6 constraints between the contentView and it's superview - 2 more than usual). Note that the width and the height can be pinned to something much larger than the normal screen size, which is probably why you are using a scroll view to begin with.
Add all of your other views you want in the UIScrollView (UIButtons, UILabels, etc. - I'm just going to assume UILabel from here on so I don't have to type as much, but any kind of UIView subclass will work) as subviews of the contentView, NOT directly as subviews of the UIScrollView
With this setup, the UILabels that are given constraints to their superview will constrain to the contentView, which has a defined size, so nothing is ambiguous.
Alternatively, if you want to fix the sizes of your UILabels (or dynamically calculate them, depending on the functionality of your app) and let the contentView expand to hold them:
Place the UIScrollView
Place a UIView into the UIScrollView to serve as a "contentView" for that scroll view
Add constraints to pin the contentView to all 4 corners of the scroll view AND pin it's width and height
create an outlet for the width constraints on the contentView (let's say we name it contentViewWidthConstraint)
place the UILabels
fix the sizes of the UILabels
create an outlet for the width constraints on the UILabels
Then in the code for viewWillLayoutSubviews
add up the widths of all of the UILabels and any gaps you want between them (as a CGFloat, which I'll call totalWidth)
set contentViewWidthConstraint.constant = totalWidth
And you're good to go! Note that I assumed you were setting the width in most of this example, but it should be just as applicable to height.
The problem is that many different widths of the two views will satisfy the constraints that you've set up. Here are two examples (I drew the shapes stacked vertically to make it easier to see the overlap example):
You can add a horizontal space constraint with a value of 0.