Button width and height is disabled in horizontal stackview - ios

Question

Im learning iOS development right now, XCode doesnt allow me to edit width and height of buttons which are in stack view:
In the Storyboard I create a new button of size 30 x 30 with a custom image and then make more 5 copies of that button. Then I embed them after selecting all of them in a Stack View. Now a disaster happens, the buttons are resized to god knows what size and they appear huge and when I try to go to size inspector to resize those buttons I see that "Width" and "Height" fields are disabled.
I tried few suggestions on stackoverflow and selected the stack view and change the distribution of stack view to "Fill Equally" but still the buttons size is being changed. I dont want this to happen. I want a fixed size buttons in a horizontal stack view and putting them in stack view should not change the size or shape of buttons like this. Can anyone please tell me how do I fix this problem?
Please help.

Answer 1

Sometime Interface Builder is not easy to handle because it is a running layout system at design-time / IB_DESIGNABLE. You make changes, IB gets triggered to 'think', changes parameters, layouts again, you see it does not fit and you change again.
It can be easier to fix UIStackView's constrains to your outer layout before dropping content that will be arranged by taking intrinsicContentSize of the subviews into its calculation. Even worse, if the stackview does not have complete constrains already and you drop something in as being arranged, it will take the default size as intrinsicContentSize of the dropped view and change the stackview spacing as it should. This is no surprise but it can be frustrating as convenience is disturbing your workflow here.
The docs tell you should not change intrinsicContentSize because it is not meant to be animated, it will even disturb animations and layout or even break constrains. Well, you can not set intrinsicContentSize, it is read-only. As thats for good reasons they could have written that while UIView's are instanced they can have supportive variables which have to be set before laying out which allows you to make pre-calculations.
While in code this can be tricky also, you can subclass UIView to make arranged subview instances more supportive to your needs.
There is UIView's invalidateIntrinsicContentSize that triggers the layout to take changed intrinsicContentSize into the next layout cycle. You still cant set intrinsicContentSize, but thats not needed when you would have a class designed like shown below.
// IntrinsicView.h
#import UIKit
IB_DESIGNABLE
#interface IntrinsicView : UIView
-(instancetype)initWithFrame:(CGRect)rect;
#property IBInspectable CGFloat intrinsicHeight;
#property IBInspectable CGFloat intrinsicWidth;
#end
// IntrinsicView.m
#import "IntrinsicView.h"
#implementation IntrinsicView {
CGFloat _intrinsicHeight;
CGFloat _intrinsicWidth;
}
- (instancetype)initWithFrame:(CGRect)frame {
_intrinsicHeight = frame.size.height;
_intrinsicWidth = frame.size.width;
if ( !(self = [super initWithFrame:frame]) ) return nil;
// your stuff here..
return self;
}
-(CGSize)intrinsicContentSize {
return CGSizeMake(_intrinsicWidth, _intrinsicHeight);
}
-(void)prepareForInterfaceBuilder {
self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, _intrinsicWidth,_intrinsicHeight);
}
#end
Now this gives you control of the behaviour when UIStackView will layout.
Let's look at instancing of your UIStackView.
#import "IntrinsicView.h"
- (void)viewDidLoad {
[super viewDidLoad];
UIStackView *column = [[UIStackView alloc] initWithFrame:self.view.frame];
column.spacing = 2;
column.alignment = UIStackViewAlignmentFill;
column.axis = UILayoutConstraintAxisVertical; //Up-Down
column.distribution = UIStackViewDistributionFillEqually;
CGFloat quadratur = 30.0;
for (int row=0; row<5; row++) {
IntrinsicView *supportiveView = [[IntrinsicView alloc] initWithFrame:CGRectMake(0, 0, quadratur, quadratur)];
// supportiveView stuff here..
[column addArrangedSubview:supportiveView];
}
[self.view addSubview:column];
}
Don't forget IntrinsicView's intrinsicContentSize is set before instancing is complete, so this example takes frame size at initWithFrame as intended and stores that size to be used when intrinsicContentSize is asked. Having that still needs that UIStackView is large enough to layout nicely but you forced the arranged subviews to that intrinsic size. Btw. the example is arranged up..down.
You can use the IntrinsicView in Interface Builder, just change the views inside UIStackView to the above written class. IB will automatically update the designable API and serve you propertys you can set up. This still needs the StackView to have at least width and height set and also constrains if needed. But it takes away the impression your width and height of arranged views would have any effect other than expected, because IntrinicViews height + width is inactive in IB then.
Just to show you how much this improves your possibilities in IB, see image