I'm having trouble getting a UIScrollView to respect the constraints I put in interface builder.
All I need to be able to do is set the content size of the scroll view from within IB.
The UIScrollView contains a single UIView.
Constraints on the UIScrollView:
Constraints on the UIView:
I've read through the documentation, and so have set things up as follows:
the UIScrollView has constraints pinning it to its superview, thus defining its size from outside
the UIView (content) has a fixed size (through width and height constraints)
the UIView is pinned to the UIScrollView, thus defining the content size
However, IB won't let me enter these constraints. If I change the 'Bottom Space' constraint between the view and the scroll view, shown in the image as -2196, to 0 (thus pinning the lower edge of the scroll view), then the 'Top Space' constraint resets to a non-zero value. The same happens in reverse. (I haven't yet tried in Xcode 5, which has a far saner approach to invalid constraints in that it doesn't just throw yours away when it feels like it.)
What am I missing?
Every time I've tried to do something even mildly sophisticated with constraints in Xcode 4's Interface Builder, I've eventually given up and either written the constraints in code or switched back to springs'n'struts and layoutSubviews (usually after crashing Xcode a few times).
That said, there is another approach to laying out a scroll view with content in IB. Just make the scroll view as big as its content size, and rely on the view controller (or some containing view controller) to resize the scroll view (or its superview) and let the constraints shrink down the scroll view's frame at runtime. The window's root view controller will always set its view's frame to the screen size, regardless of its size in the nib or storyboard, and that resizing flows down the view hierarchy.
I described this approach in more detail in this answer.
If your scroll view's content size is really supposed to be 2196 points tall, this probably won't work so well. I don't have anything better to suggest in that case.
Related
I have an OS X app originally built using Xcode 4, now using Xcode 7. When "springs-and-struts" was superseded by constraints, I reworked the UI to use constraints. Simple enough, and seemed to work well.
Fast forward two years after first release, and for the second release I needed to add controls and increase the height of the main app view. Unfortunately, my test team is using smaller screens and cannot see the whole view. They need to resize vertically.
Problem - even though the resize controls box is checked, the window cannot be resized. The controls do not show at run time. I tried
Setting lower minimum window content size height, but that did not change anything.
Changing content compression resistance did not change anything.
I am thinking this issue has something to do with constraints.... Any ideas on how to get resize to work?
Edit: After playing with a new test app some, I am more certain the problem is due to constraints. I have a control where I have constrained leading and trailing space to superview and width - there went horizontal resize.
I really need to have a view where the user can resize the window, but scroll the content. However, in this case, the content is other controls. I think on iOS, I would use a UIScrollView. On OS X, I have tried a scroll view control and have tried embedding in a scroll view, and neither have the desired effect.
I had the same issue and solved it by adding a view to be used as a "container" in the view controller.
Pin the top left corner of the "container view" to the view controller (leading space 0 and top space 0). Add equal width and height constraints on the "container view" to the view controller. Then move all your objects into the "container view" and add your object constraints on the "container view" not the view controller.
In my case, it happened in this way (Xcode 13.1).
I mistakenly added a view from IB outside of the window view hierarchy. The new view was added as a separated object (a top node in the interface builder file). I added the new view into the window by drag-n-drop.
I found the new view had different behaviours, for example, I couldn't set the top space constraint. With this view in the view hierarchy, I couldn't change the window size (content view size) at all.
I removed the view and added another in the view hierarchy, it worked as normal.
I think IB initialises the view differently if it is a separated object (top node of the interface builder file).
I'am using autolayout with NSSpliView, the setup is as following on the picture
The split view is in a window which can resize, when it resizes, the divider is changing proportional 50:50, how to change this, so that the height of the bottom view stays and the top view gets resized (but no more than 124px) but still have the freedom also to change it manually by dragging the split?
So just to recap you have three requirements,
Bottom view stays the same size on resize
Reduce the holding priority if the top view (select the NSSplitView to get the correct inspector)
Top view cannot resize more than 124px
Add a inequality constraint which sets the height of the view to less than or equal to 124px. You can do this in IB. It will also be a good idea to create a IBOutlet for this constraint in your custom view of controller class for the next step...
When the divider is moved the top view should be able to get smaller than 124px.
I not entirely sure but checkout the NSSplitView delegate method such as splitView:resizeSubviewsWithOldSize: or splitViewDidResizeSubviews:. When you resize with the divider the delegate method should override the height constraint to be the current resized size. So something like the following in the delegate method
self.heightConstant.constant = NSHeight(topView)
Or you could just remove the constraint and re-add it later when needed.
I have a window I'm setting up with auto layout. There is a view in the middle of the window that contains three controls, and I would like the window to refuse to resize horizontally smaller than the intrinsic size of those three controls.
The outer buttons both have horizontal space constraints to "stick" them to the outside of their superview, and the checkbox in the middle has a horizontal space constraint sticking it to the left side of the "Sync text" button. There is also a >= constraint between the "Sync outline" button and the checkbox, to make sure they don't overlap, but the checkbox prefers to hang to the right. All these constraints have a priority of 1000. The window itself has no minimum size specified.
When I use the "Simulate Document" command in Xcode, everything works as I'd expect, and the window won't let you size it smaller than in the screenshot above. However, when I run my application, the window does allow resizing smaller than that width, so that the buttons start to shrink and eventually the controls overlap each other. I'm not implementing any of the size related window delegate methods, so I don't see any place in the app's code where it might be influencing the resizing.
Any ideas on what could be causing this difference in behavior?
OK, I finally figured out what the heck was going on here. It turns out the problem was that I was implementing the -splitView:constraintMinCoordinate:ofSubviewAt: delegate method (as well as the maxCoordinate one) to restrict the size of the split subviews in the vertical direction. Yes, restricting the vertical resizing of the split view affected the horizontal layout of the buttons.
It appears that what happens is that, if you implement those delegate methods, NSSplitView reverts back to using autoresizing masks to layout the subviews rather than auto layout constraints. Since the view containing those buttons is no longer participating in auto layout, the buttons smush together when you resize the window small. In the simulator, the split view doesn't have a delegate set, so all the auto layout stuff works fine in that environment. Note that merely having the methods implemented is enough to trigger this, even if they just return the proposed coordinates unchanged.
The solution ended up being quite easy, which was to delete the delegate methods and replace it with a vertical constraint on the subview to restrict its size instead.
I'm trying to get the hang of NSViewConstraints. I like them a lot; they make a lot more sense to me than the previous system.
I have a window, a 22 pixel-tall subview spanning the top of it, and a tabless, borderless NSTabView beneath it. The goal is to have the top subview never resize its height.
Without any constraints, auto formatting takes care of most of the work. The only trouble is resizing the window causes the upper subview to change its height. My seemingly logical response was to pin the height at 22. I left margin constraints alone, since the NSTabView was already handling resizing well.
By pinning the height of the upper subview, the window now refuses to resize vertically! I don't see any documentation anywhere saying this is expected or the logic behind it. I've messed with various constraint configurations to overcome it but nothing works.
Two questions:
Why is pinning the height of one subview freezing window height resizing? What is Xcode's logic?
What constraint setup will achieve the desired positioning?
I just tested creating a window as you describe, and pinning the height of the 22px view. This created one user constraint on the view for it's height.
However, it also created 2 constraints on the parent view (the window's content view), one for the Top Space to the 22px view, and a second for the Bottom Space to the 22px view. These constraints are what's preventing you from resizing your window. You should select the second constraint and delete it (but leave the first one in place as it's fine).
I subclassed UITableViewController and called it FeaturedGamesViewController. Ok, I also have a navigation controller to which I added this FeaturedGamesViewController as the root. All pretty standard stuff that you do in the App Delegate.
Also note that there is no NIB file created for FeaturedGamesViewController. Just subclassing UITableViewController and calling initWithStyle sets the style of the table and sets the dataSource and delegate and size automatically. Data Source and Delegate are obviously set to FeaturedGamesViewController.
- (id)init
{
// Call the superclass's designated initializer
[super initWithStyle:UITableViewStyleGrouped];
}
OK, You see that I have set the table size to "Grouped". In Landscape view on my iPad it has about 20 pixels of space to the top, left and right (Sorry can't post screen shot because I am new here and the system won't let me until I have accumulated a certain number of points)
I DO NOT want that! This is Landscape so I expect it to fill up the all the space between the navigation bar and the tab bar below. What is worse is that I have faked a grid with a Custom UITableViewCell but the space to the left and right make it so that if you click on that space, the entire row is selected thus betraying the sense that this is a grid.
Now I figure I should resize the table view in viewDidLoad or something but I don't know how. I cannot do initWithFrame because of potential memory leaks (and possibly resetting dataSource and delegate and autoresizeMask properties that were already set) so there must be a setter or something to reset the origin of the tableview to just beneath the Navigation bar and filling up the entire screen with size 1024X748. How do you do dynamically reset the size of the table view?
Then I got really frustrated and I decided to do it via a Nib file, that way I can set the the orientation to landscape and set simulated Navigation and Tab bars and fill the rest of the space with the table view. This worked! If you are curious how to create a table view with a Nib after you have subclassed UITableViewController WITHOUT a nib, here is how:
http://developer.apple.com/library/ios/#documentation/UserExperience/Conceptual/TableView_iPhone/CreateConfigureTableView/CreateConfigureTableView.html#//apple_ref/doc/uid/TP40007451-CH6-SW10
Go to the paragraph right before "Creating a Table View Programmatically".
OK, when I did that, my landscape view of the "grid" looks filled up the entire space between the navigation bar at the top and the tab bar at the bottom just like I wanted.
I was fiddling with this some more and I found out that in my "non nib" version (the problematic one), I had set the table style to "grouped". When I changed it to "plain", it worked!!! But here is the thing though: In the nib version, "grouped" or "plain" gives the correct layout with the table occupying the whole space. So what gives?
Sorry for the long question but I guess what I am asking is:
1) How do you programmatically reset the size of the table view without introducing potential memory leaks or affecting other properties already set for you (ex: dataSource, delegate, autoResizeMask - these are set for you just because you subclassed UITableViewController)?
2) How do you do that for any view in general?
3) Why does "plain" style fill the layout as desired whereas "grouped" style gives the weird layout. Note that it this is not a problem in the Nib version.
Thanks for your patience!
Answer for (2), and hence for (1):
A UIView's frame is in a local coordinate system of its superview. A common way to make a view fit its superview is
CGRect bounds = [[self superview] bounds];
[self setFrame:bounds];
You should do this inside layoutSubviews.