Swift Center View Horizontal Ratio - ios

I am creating a view within IB and and attempting to have 3 UILabels evenly space horizontally across the view. I came across this on SO, https://stackoverflow.com/a/30249550/4597666. I have three UILabels, each have the height and width constrained. Here is what the IB looks like:
I constrained each centered horizontally, and the first UILabel I have the multiplier 3:1, second, 3:3, third 3:5 like the post states.
When I run on my emulator, I don't get the result that I was expecting. It appears all three UILabels are centered horizontally, and the first and third are not offset.
Is there another setting that I'm missing, or another way to properly space the views evenly?

you need to make only one change.
Constraint you set is 3.CenterX to Superview.CenterX all you need to do is interchange the value so that you constraint should look like in below image.
Alternative solution. If you want to set constraints currently you have set then change the ratio from "3:5" to "5:3" and similar for all the labels.
Result:
Hope it helps you solving your problem.

Related

NSLayoutContraints: How to position a bottom view below the higher of two labels?

I am working on an iOS 11+ app and would like to create a view like in this picture:
The two labels are positioned to work as columns of different height depending on the label content. The content of both labels is variable due to custom text entered by the user. Thus I cannot be sure which of the the two labels is higher at runtime and there is also no limit to the height.
How can I position the BottomView to have a margin 20px to the higher of the two columns / labels?
Both labels should only use the min. height necessary to show all their text. Thus giving both labels an equal height is no solution.
I tried to use vertical spacing greater than 20px to both labels but this leads (of course) to an Inequality Constraint Ambiguity.
Is it possible to solve this simple task with Autolayout only or do I have to check / set the sizes and margins manually in code?
You can add labels to stackView
One way to do this is to assign equal height constraint to both label. By doing this height of label will always be equal to large label (Label with more content).
You can do this by selecting both labels and adding equal height constraint as mentioned in screen short.
Result would be some think like below
The answer given as https://stackoverflow.com/a/57571805/341994 does work, but it is not very educational. "Use a stack view." Yes, but what is a stack view? It is a view that makes constraints for you. It is not magic. What the stack view does, you can do. An ordinary view surrounding the two labels and sizing itself to the longer of them would do fine. The stack view, as a stack view, is not doing anything special here. You can build the same thing just using constraints yourself.
(Actually, the surrounding view is not really needed either, but it probably makes things a bit more encapsulated, so let's go with that.)
Here's a version of your project running on my machine:
And with the other label made longer:
So how is that done? It's just ordinary constraints. Here's the storyboard:
Both labels have a greater-than-or-equal constraint (which happens to have a constant of 20) from their bottom to the bottom of the superview. All their other constraints are obvious and I won't describe them here.
Okay, but that is not quite enough. There remains an ambiguity, and Xcode will tell you so. Inequalities need to be resolved somehow. We need something on the far side of the inequality to aim at. The solution is one more constraint: the superview itself has a height constraint of 1 with a priority of 749. That is a low enough priority to permit the compression resistance of the labels to operate.
So the labels get their full height, and the superview tries to collapse as short as possible to 1, but it is prevented by the two inequalities: its bottom must be more than 20 points below the bottom of both labels. And so we get the desired result: the bottom of the superview ends up exactly 20 points below the bottom of the longest label.

Constraints to resize buttons to fit any screen - Xcode swift

I don't really understand constraints and have tried many different suggestions found online. All they seem to do is bunch everything up on top of one another or do nothing at all.
I have the following IPad application but I want it to work on any size device, mainly a IPod touch.
The page is simply two buttons that I want to remain the same no matter what screen they're on.
Any help on this appreciated.
It helps to think about points of reference that won't change with different screen sizes. Sometimes you want things on, say the top left corner so you just do constraints to the top and the left.
I'll give you two suggestions
Suggestion One
For your case, it seems like you might want to do constraints off centerY since you want them to be in the middle despite the screen size.
So I would make a constraint to "Center Vertically in Container" and then tap on the constraint and adjust it's value to negative or positive, so that way it's always X pixels above or below the centerY.
Now that's not going to be enough. it knows it's Y position but it doesn't know its height, width, or X position. So you need to add enough constraints to satisfy those.
A few examples:
X/Width: Two constraints to leading and trailing on each button OR Center horizontally and fixed width constraint. (again be careful with fixed width constraints since screen sizes can change, sometimes it's what you want though)
Height: Yeah just give it a height constraint in this case.
Note that this means no matter the screen size they'll always have the same gap between them (and maybe different gaps to the other edges).
Suggestion Two
Use a container view, either a stack view (fill, equal spacing, vertical alignment, a spacing value for gap between) or normal view.
You can make the view a fixed height based off the height and spacing between the buttons you want. Then simply center that container view horizontally and vertically on the super view.
Nonsuggestion
There are certainly other ways (like using buffer views with equal heights constraints. So you'd have an invisible view on top, a view in between and a view on bottom. and you'd give those equal heights constraints and align the buttons to the edges of the invisible views surrounding them. As long as you gave the buttons a fixed height this would work for vertical constraints) but I think these two would probably be the best.

Complex AutoLayout for Cell with dynamic size

I have a cell that contains a container with 10 subviews (two of them are simply bounds and the others are labels). The scheme looks like this.
Dynamic labels may contain huge text so the cells should conform the appropriate size to fit the content. The question is how to set up all the constraints manually... I've tried a dozen of times to do it myself but seems I'm not that good at this. The table view supports auto dimension for row height and uses custom estimated height.
In Storyboard it looks this way.
Where blue views are a subviews of View C. A grey view behind is a View B. Bold labels are static and the others are dynamic.
Demo project.
How to setup constraints?
Thank you very much in advance!
I managed to setup your constraints so that you get the result you needed. This is what I get:
I hope this is how you wanted it to look like.
Here is a link with the project.
I will try to explain how I added the constraints so that it makes more sense.
First of all, you have view B which needs to be as big as the contentView. For this you add top/bottom/left/right constraints to the superView. Because you are using automatic dimensions, if you add all constraints with priority 1000(the maximum one), you will get some error with the constraints while running. This is because, before the cell size can be calculated automatically it is zero, so the constraints crash. Therefore, I set the priority for top and trailing space with a priority of 999 so that you don't see the error log anymore. The result is the same.
Then views C needs (top or bottom)/left/right and height constraint
Then you need to add the constraints for the labels. Since you need the right ones to have multiple lines, the constraints need to specify the vertical layout for this particular case. So, you have as follows: first label: top/left to name label and right to super view. All the other have top to the previous one,and bottom to the next one.
for the labels that don't need to resize you just need leading space to parent,horizontal space to the right label and static width. Also, you will need a constraint to align the top with the label on the right.
This is the result I get:
Hope my explanation made sense, just let me know if you have questions. Good luck with your project!

Center 4 images with constraints autolayout

I'm new to autolayout and i'm kind of stuck on how to center these 4 images in all different devices like it looks on the images. i've tried to apply the auto configured constraints but then it will have that distance and that does not fit on all devices. So my question is what constraints do i need to apply on all different images in order to make all image centered with same distance?
Here is how my cell in storyBoard looks like:
image of the constraint options on image 1:
image in simulator:
/// MY TRY ////
Here you can see the constraints that i've added and the result?
result:
Your approach is almost correct, it simply lacks size constraints for the images.
If you want to dynamically resize the images and keep the space between them constant, put constraints on the images for the width to be >=20(or any other value, depends on your needs) and a constraint for keeping the aspect ratio. Then ctrl-drag from UIImageView1 to UIImageView2 and set a constraint for equal widths. Repeat that from UIImageView1 to UIImageView3 and from UIImageView1 to UIImageView4.
If you want the images to always keep their fixed size and dynamically sized spaces between them you need another approach:
The trick here is to place 3 empty UIViews between the UIImageViews so that it looks like this:
Set constraints to the top for all views
Set constraints to the left and right for UIImageView1 and 4
Set constraints for all UIImageViews to the same width
Set constraints for all UIViews between the UIImageViews to the same width
Set constraints for all the distances between the views to 0
Set the width constraints for the UIViews to >= 0
This way makes the empty UIViews between the UIImageViews to resize dynamically and all the same width.
I hope you get the idea.
For the first image add a leading space to superview and for the last image add a trailing space to superview and add vertical spacing between first and second, second and third, third and fourth and also set horizontally center within the container to each of the images
The objects on your storyboard require at least 4 constraints per object.
When there's orange lines around the UIImageView object like appears in your question, this means a constraint is missing, or conflicting and can often mean the image does not display at runtime like you'd expect.
In the first instance I recommend you select all objects and 'clear constraints', then start again.
Although not exactly the same, here is a link to an answer which explains the auto-layout constraints in a bit more detail. Once you understand it, auto-layout can be very powerful.
>>Link to similar auto-layout issue - iOS CustomTableViewCell: elements not aligning correctly<<
I hope this helps
If you want the images to always keep their fixed size and dynamically sized spaces between them then very easiest way first you drag the four UIView in your StoryBoard
set constrain top left right and height for all the UIViews and give the equally width to all the UIViews(drag from one UIView to another and sets its equally width repeat this work for all the UIViews).
Image about layouts
Secondly you have to drag your images set in these UIViews and sets their constrain height width and centre horizontal in container and centre vertically in container.
In last set the background colour of all UIViews default(white) you get the result it will work....i assure.
Screenshot of Xcode

How to center horizontally two labels?

I have pretty straightforward requirements where two labels must be centered horizontally. So, I have selected them and chose Editor->align->center horizontally. Then added top space to container constraint to both of them. I also need the labels to shrink/grow regarding content size. However, IB shows errors and several warnings. I could make the labels shrink/grow just by adding pin between them (horizontal space) but they will not be centered in that case. Here are the screenshots:
here are the errors and warnings:
UPDATE theraven gave an interesting suggestion to use dummy view for centering it horizontally and pinning two labels to it. I have removed all existing constraints, added this dummy view and center X + center Y constraints to it. Then pined two labels to it (added horizontal space constraints). However, I still get a bunch of errors and warnings:
UPDATE2 Just updating the question, but still no valid answer found. #Theraven workaround works for iPhone4, iPhone4S, iPhone5 and iPhone5S, however it's not real centering but rather a workaround. Therefore for iPhone6 and iPhone6 Plus it doesn't work as leading and trailing spaces will be fixed and won't automatically resize for larger width.
What you could do is add both labels to another view, like a container view. Then you need to center this one horizontally and add the necessary constraints.
To add the containing UIView, you can select both labels, go to Editor -> Embed In -> View.
Then you would need to add constraints to make the containing view fit the two labels. So something like this:
First Label (left one):
Leading Space to Superview
Top and bottom Space to Superview
Horizontal spacing to the next Label
Second Label:
Trailing space to superview
Top and Bottom to superview (or align top with the first one)
Then the containing view should resize as to fit both labels. Then all you need to do is add the top offset constraint for this container view and a horizontal alignment it in the parent view.
This way, the containing view will grow as much as it needs to fit both labels and the space between them and will always be centered in the parent view.
I took a screenshot of my test constraints in case it helps you more.
Hope this was what you were looking for.
To solve this use a blank UIView in between your two labels and center it horizontally. Then pin the two labels either side of the centered blank view. It is common convention to use spacer views like this in auto-layout.
I really don't like the idea of adding another view just for sake of estethic.
Another alternative is to horizontally-center the left view, and horizzontally space the right view of an amout X with the left one.
Then to give the horizontally-align contraint of the first view a negative value equal to the first view width plus half the views distance. Or use multipliers as said in a previous comment.
But this only works with fixed width views i guess.
Use centered UIStackView as a container for two labels with a spacing required.
I didn't really understand what you wish to do.
The error you get (in the first screen shot) is that you are missing constraint for the x position of the labels.
For UILabel you must have constraint both for y and for x position regarding to the container view, when you selected them both and chose Editor->align->center horizontally, you just say that label1.center.x = label2.center.x.
You still need to say where they will be in the container view, you added the top space to container, so you do have the y position, but you didn't say where the x position should be.
You said
I have pretty straightforward requirements where two labels must be centered horizontally
But where they should be in respect to their container?
thanks
Using spacer views is the best possible solution I could figure out, even though it looks ugly for the developer. The user wouldn't even know what's going on behind the scenes and once you have the spacer UIView, you can always reuse it.

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