In the diagram I need to center align the right view with the left view. If the right view is larger than the left view I need to top align it. Can I do this with constraints (storyboard) or do I need to do something in code to adjust the position (via a constraint) of the right view after the size has been determined? The Right view has multiple UILabels that can grow so I don't know the size until runtime. The container is actually a UITableViewCell.
Centering is easy. The right view resizes and the cell adjusts to that size. The issue is the requirement to top align if its too big.
You want this:
You can do it with two constraints.
You want the top of the green view to be greater than or equal to the top of the pink view, always. That is, you require that green.top ≥ pink.top.
In addition, you want the Y-center of the green view to be equal to the Y-center of the pink view, when possible. That is, you prefer that green.centerY == pink.centerY, if it doesn't violate the other constraint.
Here's the first constraint, in the storyboard editor:
And here's the second constraint:
Note that I have lowered the second constraint's priority to 800, which means it's not required but it's strongly preferred.
You don't need to write any code to make this work. I did write code in my demo to wire up the slider and the label, but I didn't have to modify those two constraints from code.
In the storyboard, align the right view to the left view top.
Give the value as
topAlignCons.value= +(leftView.height/2) //in storyboard
so that it gets align to the center of left view
Create an outlet for the top align constraint in your view controller.
When the right view is larger that left view, change the outlet constraint value to 0.
topAlignConstraint.constant=#0;
Now it will be aligned to the left view top with no negative value.
Related
I have a cell in which I place four buttons and four labels. Each button gets assigned a picture with width 50 and height 50. Furthermore, all buttons have a corresponding label describing what they're intended for.
My objective is to have the buttons and labels resize to keep the buttons' and labels' aspect ration intact while the screen dimension changes on different devices. I have been playing with auto layout changing the hugging and compression to achieve this but haven't been successful yet. Any help would be much appreciated...
I think you should take a look at a UIStackView, because this seems exactly as a use case for stack. Just put each pair button/label in a stack, and then all four pairs into a horizontal stack, which you constraint to the cell itself. You should be able to handle all you need just by configuring the stack’s properties (axis, distribution, alignment, spacing).
Embed your button and label into a view. Set the width of this view equal widths to content view and change the multiplier value to 1:4. This will adjust the widths of the views according to superview. Also, set the top and bottom constraint to 0 for this view.
Provide center align y-axis constraint to button after setting the width and height constraint to 50. Set its top constraint to a value you deem fit.
Set labels's leading and trailing constraint to a value like 8. Choose center alignment for text. Also, provide top constraint to buttona nd bottom to its superview.
Copy the view and paste to create the three views and provide them equal widths constraint to the first view. Also, provide their leading, trailing, top and bottom constraints.
Here are a fast tutorial in how to achieve that:
1-
2- completion of the first Gif:
Note you can achieve the same output using a UIStackView
I have a weird behavior when I use scrollView.
As you can see in the picture bellow the button called "Back" has a bottom space constraint with value 0. But we can see is not even near to the bottom of the scroll view.
I already set the scrollview to have equals width and height of the superView and top,bottom,trailing and leading space with 0 value.
How can I fix this? I want the Back button still inside of the scrollview and put it at the bottom of the view.
Update
I have the code here https://github.com/rchampa/NDParallaxIntroView and the xib is called PageB.xib
Ricardo: you've added two constraint regarding manage y position of Validate Code button where your top constraint stop to move Validate Code button towards the bottom. So please remove top constraint of Validate Code only add bottom constraint.
you need to manage all constraint like your scrollview content view height will be equal to height. Please increase some top constraint from top.
So, if I understand correctly, the problem you are running into is that your back button is unable to be positioned based on the bottom of the scroll view.
A scroll has two sets of constraints in a storyboard, one that defines the size of the scroll view, and the other that defines the content size. The top, left, bottom, right to superview constraints on the scroll view will define the size.
The part that is causing your problem is that the content size is defined by the subviews inside the scroll view. So the button cannot be placed relative to the bottom of the scroll view since the scroll view doesn't know how large its content size is. All of the subviews of a scroll view must be placed in relation to each other.
So, create constraints for your logo, text fields, and all the buttons in relation to each other. Then create constraints from the outer most subviews to the scroll view.
In your example, you would constraints from the logo to the text field, 1st text field to 2nd text field, then 2nd text flied to the label, label to the "Send email..." button, and finally "Send email..." to the "Validate Code". For the "Back" button, it would need a left align with the text fields and then a center align with the "Validate Code" button. Create a top constraint from the logo to the scroll view. Then have leading and trailing constraints from one of the text fields to the scroll view. Finally, create a bottom constraint from either the "Back" or "Validate Code" buttons to the scroll view. You will also need some alignment constraints (logo center to the text field is an example of one). After that is all setup, your view will be fully defined for the content size of the scroll view.
If I understand you, my new question is: how can I make the subviews
make the height of scroll fit 100% screen device height? Is there a
way to define weights like Android? I don't know how achieve this
since the canvas is 600*600 which is different to every device.
Response would be too long for a comment:
So you wouldn't use a scroll view for that. A scroll view is specifically for containing content that will not fit on the screen (so the user can scroll to reach the new content).
The simplest solution is to add a regular view that has TopLeftBottomRight 0 distance constraints (so it is the max height and width of the screen) and setup the view like you have here to position the bottom in the bottom left all the time.
There is also a weight system, I can explain that if you want, but it wouldn't be required thus far.
I feel like your next response will be something like "what if I want it to scroll when its too small for the current screen?". The only way I know of doing that in encapsulating all your interface into a single UIView, and changing its sized in the viewDidLoad/viewDidAppear based on the size of the scroll view. Something like this:
func viewDidLoad() {
super.viewDidLoad()
containerViewHeightConstraint.constant = scrollView.frame.size.height
containerViewWidthConstraint.constant = scrollView.frame.size.width
}
So I'm just trying to wrap my head around Auto Layout; I understand how to use constraints, just not how to apply them appropriately. In the picture below I had set no constraints and simply want this simple design to resize correctly on all size classes (Horizontally and Vertically).
http://tinypic.com/r/2ymxbop/9
What constraints would I need to put in to have these squares resize appropriately on all screens (horizontal/vertical) and can you do this in the ( W:Any H:Any ) size class or do you have to set constraints for each individual size class?
Thanks!
One size class is all you need in this case.
Set a constraint for each of the 4 gaps between the rects (i.e. the space between the top 2, between the top-left and bottom-left, ...).
Set a constraint for each rect to its 2 closest outer edges.
Now you've set four constraints for each rect - and that's all you need!
For that case: follow the steps
1.Add four uiview to screen, two top and two bottom.
2.In your case the view not touching to bottom layout guide,so you have to give fixed height.
Start the add constraints to views.
All views are correct width and height.
3.So take first view from left top,give leading space ,top space and adjecent spacing to right top view. And select the pin button from the canvas below right side option availabe, select height ,give how much height you need.
4.Now select right top view ,give constraint to top layout guide and trailing space.and also same height what you selected before for view one.
5.Now view three ,left bottom view , give leading ,spacing to top view and right spacing to fourth view and select same height .
6.Now fourth view, give spacing to top view ,trailing to container and select height.
Almost completed.
7.Select all views at once ,give equal withs(option available in pin).
lastly some warning will shows ,do update frames.
Say I have 2 views (labels or textfields) with varying heights positioned above each other (not on top). I would like the group centred vertically in the superview.
I know I could use a dummy spacer view above and below and set equal height in storyboard. I'm no expert, but this doesn't seem right to me.
Can it be done in storyboard by setting the top constraint for the top view equal to the bottom constraint of the bottom view?
If your subviews' heights will change at runtime (either because you change the number of lines of text in them, or because you support Dynamic Type like a good iOS app should), then no, you cannot do this with just constraints. You either need an extra view or you need to change the constraint constants from code. If you go with an extra view (which I recommend), you can do it with a single extra view.
The simplest solution, if your deployment target is iOS 9 or later, is to put your subviews into a vertical UIStackView and center the UIStackView in the superview. You might not need any constraints directly on the subviews depending on the layout you want.
If you can't use a stack view, you can use a spacer view. First, set up vertical spacing constraints between your subviews to glue them together with whatever padding you want. Then add a spacer view next to the subviews. Set the spacer view to hidden. (Hidden views still participate in layout.) Constrain the spacer's top edge to your top subview's top edge, and constrain the spacer's bottom edge to your bottom subview's bottom edge. Then constrain the spacer to be vertically centered in its container (which should be the superview).
You also need to add horizontal constraints on the spacer to keep Xcode from complaining, but the horizontal size and position don't really matter since the spacer is hidden. So just put it somewhere convenient.
Here's the final set of constraints and layout:
The spacer is the skinny pink view.
You can achieve it easily via center vertically, control and drag the object you want to centre in Storyboard, choose center vertically in container. This way you can centre these subviews in superView individually. If you want to centre these subviews together, you can create another containerView to contain these views(labels, textFields), then centre the containerView in superView.
Hope this help:-)
Control and drag in Storyboard
Center three subView individually.
Center them together with a container view
I want to horizontally center multiple UILabels - as a group - on a line in Interface Builder. One the straight view controller i could not figure out how to do this. I read comments about place the UILabels in a View and then centering the view in the view controller. When I tried this, overtime I said to update frames in the interface builder, the View would be resized down to nothing. (i.e. its height and width would be set to 0 by IB). I need to know how to get this to work in interface builder.
An example of a line containing multiple labels I want horizontally centered is below. The braces simply indicate the start and end of each label and are not art of the text. The <- 6 -> is meant to indicate the trailing space from label 1 to label 2 is 6
Label 1 Label 2
[Rating: 0.0]<- 6 ->[Distance: 125.34 Kilometers]
Any suggestions would be greatly appreciated.
Here is an EXACT example of what I have done and it does not work:
Create a new view controller in IB
Place a page label at the top of the page centered horizontally and aligned to the top of the layout guide.
Add a view with the following constraints on the page:
Now add two labels to the view with the following constraints:
Once this is done I get the following error and updating the frames will cause it to be give a height and width of 0
Here is what the page looks like in IB:
I need the height and width of the view to size automatically so that I have put a multiline label in the view and have all the contents of the view treated as a group and centered on the page.
Any suggestions would be greatly appreciated.
Here is a snapshot of a working set of all the constraints on an abbreviated layout that produces an always-centered view that automatically resizes with the child views (i.e., as the content of any label changes, the view grows or shrinks around it).
Important to your solution, the view has neither a height nor width constraint; its size is constrained entirely by its descendant constraints.
The key is that every component has a direct or indirect constraint from which its size and position are specified or can be inferred. For example, in order for the view to infer its width, the child labels must have a leading space constraint on the first label, a trailing space constraint on the last label, and a horizontal space constraint between interior labels. Those constraints plus the contents of the labels allow the width of the view to be inferred ... and force the view to dynamically conform to that width.
The same applies for the view's height. For example, you can specify the top and bottom space of just one label, or all of them. If just one, the remaining labels can be vertically aligned with it (see "Align Center Y to: Label1" in the screenshot).