I am leaning iOS programming in objective-c. In Xcode, I am trying to add stack view that encompass a table view. However, the storyboard showed some warning or error that indicates I should set constraints to the stack view and the table view as well in the Y-axis as well as adding constraint.
I spent some time to find out how to set that right, but at the end the stack view because distorted and appears as shown below in the image.
Please advice and let me know how to adjust the constraint of stack view and its included table view.
imageView
[![attempt to add constarint to stack view][1]][1]
[1]: https://i.stack.imgur.com/UJdyn.jpg
Im not understanding your question very clearly but one thing i think you are missing is the understanding of how a stackview works .
Stack views are given a defined size at the begining and depending on the views inside the stack view it has the ability to change its height and width. Thats the whole point of using a stack view . So if you are having a stack view inside a . table view what you should do is givena constraint to the stackview depending on which way you are adding the elements .
If you are adding the elements in a verticle manner , you have to set the stack view positioning constraints from leading and trailing. The reason is if the elements within is added verticle there is no reason for the horizontal alignment to change hence you give a constraint horizontally .
However if you add the elements horizontally , you give a constraint to the top and bottom of the stack since then there is no reason for that to change .
and the stack will change its size (width or height) depending on the element sizes within.
Related
I want to add margins or paddings on the right of some nested UILabels
like shown here:
Using trailing spaces on the labels seems wrong and old-school somehow.
Any way to make that more elegant on interface builder?
Just add a spacer view at the end of the horizontal stack view. Set its color to clear. Give it a width constraint to fix its size.
Or, judging from your screen shot, it looks like you could just move the right edge of the top-level stack view (child of MasterCell) to leave a margin.
UPDATE
You can set layout margins on a stack view, in the Size inspector:
Maybe you just want to set the right layout margin.
If you set the stack view's layout margins in code (the layoutMargins property), you must also set its layoutMarginsRelativeArrangement property to YES.
Similar question: How to resize a parent view based on the size of subviews layouted with Autolayout
I got an NSStackView which loads DisclosureViewControllers (NSViewController subclasses) just like in the Apple Example InfoBarStackView.
Those can expand and retract views of arbitrary height.
I would like the parent view containing the NSStackView to resize its height according to the contents of the NSStackView. In the Apple example that works.
However, unfortunately, Apple is resizing a NSWindow and I am using a CCNStatusItem (CCNStatusItem Github), a view that attaches to the status item in the Apple menu bar. That window resizes to the contents of the NSStackView when it loads, but doesn't resize when the contents change.
When I expand a section, the content overflows and gets clipped on the bottom edge of the view.
I went through all the constraints and tried to reproduce it exactly, but couldn't get it to work. In the Apple example, they are adding everything programmatically, whereas I added a NSStackView in Interface Builder.
Here are the constraints of the NSStackView:
My question would be: What constraints do I have in the Interface Builder (with what priorities), so that the parent view (the window) resizes with the contents of the stack view dynamically?
Do I have to call some method of the view to make it work?
Please let me know if I missed to provide some necessary information.
UPDATE
The accepted answer was the right way to do it. Here's the result. My forked version of CCNStatusItem can be found at https://github.com/julianvogels/CCNStatusItem.git
When using auto layout constraints, you don't need to call a view method to cause this effect, but just make sure that:
the views inside the stack view have constraints that will cause them to grow
the container has constraints to the stack view that indicate the container should grow with the stack view
the container doesn't have any constraints that would prevent it from growing
The screenshots seem to indicate it's not the first -- the views are growing as expected. So it could be either the second or third. The screenshot from interface builder seems to show that the bottom StackView<>Container constraint is optional (it's dashed). Depending on what the priority actually is, that could be your problem. Based on the design you described, there should be no reason for that constraint to be non-required.
The problem is that CCNStatusItem is not auto-layout-compatible. It sets the content view of its window to an instance of one of its own view classes (CCNStatusItemWindowBackgroundView). Your view is a subview of that view.
When it creates and adds its view, it does not turn off translatesAutoresizingMaskIntoConstraints or use constraints to position it relative to its superview. That basically means it can't be forced to a different size by constraints.
Likewise, when it adds your view to the background view, it does not turn off translatesAutoresizingMaskIntoConstraints on your view nor does it set up constraints to relate your view to the background view.
Since you've got the source, you can make those changes.
In order to implement scroll view I do:
Create Cocoa Application
Go to XIB
Drag scroll view to the view window and set its constraints to 0
Everything seems fine until now
Under Bordered Scroll View (in the Document Outline) I press on Clip View and then View and resize that to any large number (under size inspector)
I add a button (for the sake of it) to the view (under clip view) (in the Document Outline) and sets its constraints
After this I immediately get the "Ambigious Layout. Position is ambigious for "View".
What am I doing wrong? Is this the proper way to add scrollview? It also seems rather difficult to add items to the scrollable area as I dont see the entire scrollable area in the xib.
Please help a noob.
In general this is a correct way to add a scroll view. (You can also create a view or set of sibling views, select them, and choose Editor > Embed In > Scroll View.)
If a view has no constraints, then Xcode will add sufficient constraints at build time. These constraints are not necessarily the ones that cause the view to behave like you want as things change size, but they're good enough to maintain the current layout of the canvas when things have their current sizes.
However, once you add constraints, Xcode will start insisting that the constraints are mutually-compatible (no conflicts) and sufficient to be unambiguous.
So, that explains why you get that warning. You have added some constraints, but not enough to make the layout unambiguous. You need to add enough. Xcode should explain in more detail what's needed, although there will necessarily be multiple possibilities for how to resolve the ambiguity.
In your case, I'm guessing that the size of the view in the scroll view is ambiguous. For example, you may have added constraints to position the button relative to the top and leading edge, and the button likely has intrinsic size, but you haven't constrained the view's bottom or trailing edges to the button. So, the size of the view could be anything.
Of course, rather than constraining the view's bottom and trailing edge to the button, you could just add explicit height and width constraints to it. Or whatever.
You may also need to constrain the view to the clip view.
You can also use Editor > Resolve Auto Layout Issues > Add Missing Constraints and see what Xcode adds. You can then change things from there if what Xcode added is not what you want.
For my Mac OS X app, I selected the controls on xib to embed in scroll view ( Editor > Embed In > Scroll View ) and applying the following constraints to Custom View (inside Scroll View -> Clip View) did work.
Where hight is to accommodate controls.
I know this question has been answered before, many times, but my use case seems to be just different enough from all of them that I can't quite figure it out.
My Problem
I have a scroll view that is not the same size as its superview. The scroll view has 1 subview that is the same size as it, but it needs to be able to be pinch-zoomed.
Attempted Tutorials:
(1) - Apple's Technical Note - This is done only with code and the examples show only full screen scroll views.
(2) - Natasha The Robot's Article - This was a really well written article but I could not get it to work for me. I think it's due to the fact that her scroll view is full screen.
(3) - Happy Coding Blog Article - Another full screen scroll view
... and lots other tutorials that were very similar to these
My requirements
My scroll view needs to be full width
My scroll view needs to be 40pt from the top and have a 1:1 aspect ratio
My scroll view needs to have one subview that is the exact same size of it but can be pinch-zoomed (aka content size = scroll view size)
I don't think that the size of the scroll view should impact anything, but it appears to.
What I have tried
As all the tutorials above recommended, I have only a single subview of the scroll view and have aptly named it "Content View".
View Controller
|-View
|-ScrollView
|-ContentView
|-ZoomableView
Here is a picture of my constraints:
As you can see, I have an equal width set up from the "Grid" (Zoomable view) to the view controller's view. I've also tried adding an equal width of the content view and the VC's view.
My question
I know I can get this to work with an explicit width and height, but I know I should be able to get it by setting the width equal to the view's width and height equal to the view's width as well (AKA 1:1 aspect ratio). How can I achieve this?
I think I ran into the same problem in the past. What I end up doing was adding a "container" view and use it to set up my width and height equality constraints instead of the view controller's view.
This setup will produce what you want I think: a scrollview with 1 subview that can be pinch-zoomed in the view controller's view (grey in the screenshot) but with a top margin of 40pt.
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.)