I have a relatively simple portrait-only UI, laid out in a Storyboard, with items which I want to vertically spread to fill both 3.5 inch and 4 inch screens.
In other words, I want the spacing between the controls to be adjusted so that the UI nicely fills the screen, irrespective of the screen form factor.
This doesn't seem like an unusual thing to want to do, however I just can't get Interface Builder (within Xcode 5) to add the right constraints - I only seem to be able to get it to add fixed vertical space constraints, which do not adjust for different screen sizes.
Does anyone know how to do this without resorting to programmatic UI construction? I've invested a lot of effort in getting the Storyboard-based UI just right.
The solution needs to work on both iOS 6 and 7. Thanks!
How to do this depends on exactly what kind of adjustment you want when the screen size changes. One way to do it to give the top and bottom most views vertical spacing constraints to the top and bottom of the superview, respectively. Add a view, I usually use a UILabel with no text, in between all the views you have stacked vertically, and give them equal heights to one another. Give one of those "spacer" views a fixed height, but edit it so its priority is less than 1000 (which means it's not mandatory that it be satisfied). Then add spacing constraints between each nearest neighbor above and below each "real" view and the "spacers", so that you have all the views from top to bottom connected together by vertical spacing constraints. When the screen size changes, the only thing that can change will be the height of the "spacers", since the priority is less than 1000, and all other constraints are mandatory. My constraints look like this:
The labels each have the standard (8 point) spacing to the "real" views above and below them. The top and bottom views should have whatever spacing you want to the screen edges.
Apple have now posted a document which describes the officially-endorsed approach to solving this problem:
https://developer.apple.com/library/ios/documentation/userexperience/Conceptual/AutolayoutPG/AutoLayoutbyExample/AutoLayoutbyExample.html#//apple_ref/doc/uid/TP40010853-CH5-SW8
Summary of the approach: insert spacer views between your controls, which have equal width/height (as applicable) constraints.
Related
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.
I would like to center four buttons horizontally and vertically. Each of the buttons shall get a background image later, so I think it's important that the aspect ratio stays more or less the same, otherwise the pictures won't fit onto the button.
A screenshot of what it should look like:
All buttons have the same size and should take up as much space as available (small margin, 10px or so, not more if possible). I don't know how to set the constraints that the application looks good on all devices (iPhone 5s and iPad 10.5").
The application must not necessarily run in all orientation modes.
How do I have to set the constraints?
This problem can easily be reduced to the problem of making a maximum square centered in its superview. You can do that easily with just four constraints:
The rest — the grid of buttons — just falls into your lap. For example, make my blue view a UIStackView containing a two UIStackViews, and there's your grid. Or you could do it with explicit constraints yourself.
If this app can rotate, you might need two sets of constraints, one for when the width is less than the height, the other for when the height is less than the width. You would then have to swap them in code. But that's another issue, and is not difficult.
Add them to UIStackView, for placing them horisontally use horisontal value for axis property you can customize it with distribution, alignment and other properties of UIStackView.
It's the easiest way
I need my buttons to stay in the same positions for all phones.
I want it to look like this on all iPhones:
But when I switch to a larger size phone it does this, it also looks ugly on smaller phones as well:
That is a VERY broad question, as a lot of iOS UI depends on autolayout. I suggest you work through these tuts at at least AutoLayout. From your screen shots, it looks as if you have set a width constraint on your view with the green background instead of pinning the leading, trailing, top, and bottom to the edges.
Auto layout is, in essence, a system that performs calculations based on constraints. This means that to perform what you want, you need to add constraints to each of your objects so that the compiler knows how you want to resize your UI. But like others have said, that is a very general question. I suggest looking into the topic a bit before asking, so you can narrow down your question and get better answers.
You need to define positions for all your button or views. You need to define atleast 4 constraints for all your view. By adding constraints you tell your views where they should be placed on all screens. You define their positioning with respect to screen by adding constraints.
When you add trailing, from top and width and height constraint you tell that view should be placed in fixed position i.e. x , y and occupy defined space whatever may be screen size.You can opt for fixed width or height. Instead of fixing height and width you can also define leading or trailing constraints for the view. Constraints will adjust views frame according to screen size.
For beginning you can opt for some tutorials available online. You can check Raywanderlich here. Hope it helps.
I understand the old Struts and Springs method of aligning, sizing and distributing views in Interface Builder. However, I cannot seem to figure out how to evenly distribute views using auto layout with Xcode 5. There was a way to do it using Xcode 4, but that option is gone.
I have 7 buttons arranged in a vertical stack. On a 3.5" layout, it looks great. When I preview the screen in the 4" layout, all of the buttons remain tightly packed and there is a large amount of space below the last button.
I want them to stay the same height, but I want the space between them to be able flex so they can spread out across the screen.
I've been able to get the height of the buttons to flex and fill the space, but that is not my desired behavior. I would like to learn how to use Auto Layout to replace my old Springs behavior, but I can't seem to find any way to do it through Interface Builder.
I'm ok with the top button either being a fixed space from the top edge or a proportional space from the top edge, likewise for the bottom button and the bottom edge. Those are less important to me, I'm good with either.
But I really need to figure out how to evenly distribute the extra space between each of the items in the view.
EDIT Note that in iOS 9 this technique will become unnecessary, because a UIStackView will perform distribution automatically. I'll add another answer explaining how that works.
How to Perform Even Distribution Using Autolayout
The simplest way to do this in Interface Builder alone (rather than constructing constraints in code) is to use "spacer" views:
Position the top and bottom buttons absolutely.
Place spacer views between all the buttons. Use constraints to position them horizontally (centering them horizontally is simplest) and to set their widths.
Make constraints between each button and the spacer view above and below it, with a Constant of 0.
Now select all the spacer views and set their heights to be equal.
The first screen shot shows me setting this up in IB:
I have deliberately not corrected for the "misplaced views" because I want you to see what it looks like while I'm designing the constraints. Here's the result on both a 4 inch and a 3.5 inch screen:
I have left the spacer views black, just to show you how this technique works, but of course in real life you would make them transparent and hence invisible! So the user sees just your buttons, evenly distributed on either height of screen.
The reason for the use of this technique is that although the notion of equality performs the distribution of values you are asking for, constraints can apply equality only between aspects of views; thus we need the extra views (the spacer views) so that we have things we can make equal to other things (here, the heights of the spacer views).
Other Approaches
Obviously, a more flexible approach is to assign the constraints in code. This may sound daunting, but there's a lot of third-party code out there to help you, such as this sort of thing.
For example, if we have a (possibly invisible) superview whose height acts as a boundary to dictate maximum vertical distribution of our four buttons, we can pin their tops to the vertical center of that superview with a constant of 0 but a multiplier of 0.000001, 0.666667, 1.33333, and 2.0 respectively (if we have four buttons); now the buttons will stay vertically distributed even as the superview changes size in response to screen height or whatever. [In Xcode 5.1, it will be possible to set that up in Interface Builder, but in earlier versions of Xcode it is not possible.]
In iOS 9 / Xcode 7 this problem will be trivially solved in IB. Simply select the buttons (or whatever it is you want to distribute vertically) and choose Editor > Embed In > Stack View. Then you simply configure the stack view:
Provide constraints that position and size the stack view itself. For example, pin the four edges of the stack view to the four edges of its superview.
Set the stack view's attributes. In this case we want Vertical axis, Fill alignment, Equal Spacing distribution.
That's all! However, you may be curious about how this works, because it is still possible to do the same thing manually in code. A stack view performs distribution, not by inserting spacer views, but by inserting spacer guides. A guide (a UILayoutGuide) is a lightweight object that behaves like a view for purposes of layout constraints, but is not a view and therefore doesn't have to be made invisible and doesn't carry any of the overhead of a view.
To illustrate, I'll do in code what the stack view is doing. Presume we have four views to distribute vertically. We assign them constraints for everything but their distribution:
They all have absolute height constraints
Their left is pinned to the superview's left, and their right is pinned to the superview's right
The top view's top is pinned to the superview's top, and the bottom view's bottom is pinned to the superview's bottom
Now, presume we have references to the four views as views, an array. Then:
let guides = [UILayoutGuide(), UILayoutGuide(), UILayoutGuide()]
for guide in guides {
self.view.addLayoutGuide(guide)
}
NSLayoutConstraint.activateConstraints([
// guide heights are equal
guides[1].heightAnchor.constraintEqualToAnchor(guides[0].heightAnchor),
guides[2].heightAnchor.constraintEqualToAnchor(guides[0].heightAnchor),
// guide widths are arbitrary, let's say 10
guides[0].widthAnchor.constraintEqualToConstant(10),
guides[1].widthAnchor.constraintEqualToConstant(10),
guides[2].widthAnchor.constraintEqualToConstant(10),
// guide left is arbitrary, let's say superview margin
guides[0].leftAnchor.constraintEqualToAnchor(self.view.leftAnchor),
guides[1].leftAnchor.constraintEqualToAnchor(self.view.leftAnchor),
guides[2].leftAnchor.constraintEqualToAnchor(self.view.leftAnchor),
// bottom of each view is top of following guide
views[0].bottomAnchor.constraintEqualToAnchor(guides[0].topAnchor),
views[1].bottomAnchor.constraintEqualToAnchor(guides[1].topAnchor),
views[2].bottomAnchor.constraintEqualToAnchor(guides[2].topAnchor),
// top of each view is bottom of preceding guide
views[1].topAnchor.constraintEqualToAnchor(guides[0].bottomAnchor),
views[2].topAnchor.constraintEqualToAnchor(guides[1].bottomAnchor),
views[3].topAnchor.constraintEqualToAnchor(guides[2].bottomAnchor)
])
(Obviously I could make that code cuter and shorter using loops, but I have deliberately unrolled the loops for clarity, so that you can see the pattern and the technique.)
Auto contraints seems like a bit of a chore. I have a bunch of elements in my main view (this is a single-view app) inside Main.storyboard. So imagine a few labels, buttons, controls, etc.
For example, take one label that says "Hello World" that's centered horizontally in the upper portion of the screen.
I need to add the following constraints to make it appear "normal" in my various devices ipad/iphone:
Horizontal Center constraint
Leading Space
Top Space
Trailing Space
It works, but it seems like a lot of work, I don't remember doing this work in the good old days (~3 years ago) with struts and springs. So I need to add all these constraints to each of my other elements too. So if I have 10 elements, I need roughly 10x4=40 contraints? Is this the ideal way to do this?
If it were up to me a view and the elements as I place them in the view and all controls in it would just be stretched relatively to fit the size of the device. An example would be like in photoshop, where we just decide what the overall image looks like and then scale the image to just fit the dimensions that we want. Is this possible in xcode?
Note that my app is just portait only - for iphone/ipad, but looks exactly the same in both (ie same layout for the controls)
You don't need to set that many constraints.
Horizontal center + top space would be enough given your example, or leading, trailing and top space.
If you are setting leading, trailing and horizontal center, you are over-specifying in that axis and possibly giving the auto-layout system contradictory information that will cause problems.
For that specific example: no, you only need a horizontal center and a top space, because UILabels have an intrinsic content size so their width and height is specified by their content and not constraints (unless you want them to be).
You didn't do this work in the good old days because Auto Layout wasn't on iOS then and there was only one particular possible iPhone size at the time: now there are 4. Auto Layout is an essential tool for modern iOS development.
As for controls stretching relatively to the device size, it depends on the control, but in general standard controls maintain the 44 point touch target rule - for example nav bars have gotten wider to accommodate wider phones but they haven't gotten any taller, because the larger screen size should be used to display more content instead of more chrome.
But yes, if you wanted to have controls have particular dimensions based on device size that is definitely possible with Auto Layout.