Hello list,
Thanks to someone on the list who provided me with a clue, I found that if I
add this to my NSCollectionViewItem subclass:
override func viewWillAppear() {
super.viewWillAppear()
view.removeConstraints(view.constraints)
view.addConstraint(NSLayoutConstraint.init(item: view, attribute:
.width, relatedBy: .greaterThanOrEqual, toItem: nil, attribute:
.notAnAttribute, multiplier: 1, constant: view.frame.size.width))
view.addConstraint(NSLayoutConstraint.init(item: view, attribute:
.height, relatedBy: .greaterThanOrEqual, toItem: nil, attribute:
.notAnAttribute, multiplier: 1, constant: view.frame.size.height))
}
the Collection View loads as expected and all the items appear at the proper
size regardless of window resizes. However, I do end up with a large number of
NSAutoresizingMaskLayoutConstraint clash errors. Not quite sure how I’m going
to resolve this yet, but I thought I’d post it in case anyone else follows in
my footsteps.
Cheers,
Arved
> On 2019-10-20, at 21:54, Arved von Brasch <co...@atgo.org> wrote:
>
> Hello Cocoa List,
>
> I’m in the process of porting a hobby project to up-to-date Swift so it can
> be used on Catalina (and I can upgrade my work machine - still looking for a
> QuickTime 7 Pro replacement, though). I’ve encountered a phenomenon
> subclassing NSCollectionViewFlowLayout that I haven’t been able to resolve.
>
> I have a Core Data backed NSArrayController feeding data to a
> NSCollectionView (still using XIBs, as that made the porting easier). That
> all works fine, although was surprisingly tricky to get going. I implemented
> a NSCollectionViewFlowLayout subclass to provide a left justified layout. I
> then implemented the NSCollectionViewDelegateFlowLayout function
> sizeForItemAt: to provide custom sizes for my items. This all works as
> intended during testing when the collection view is first loaded. However,
> if I resize the enclosing window, all the items reduce in size to what
> appears to be a single pixel and I can’t work out where the tiny size is
> coming from. My output of sizeForItemAt always seems to have sensible values,
> and I can’t see an obvious place for where else the collection view would be
> getting sizes from.
>
> I’m only implementing an init function, to set the estimatedItemSize,
> sectionInset and spacing values, and then overriding
> layoutAttributesForElements, as that seems to be all that’s required for my
> use case. I do not have any headers or footers or sections in my scenario, so
> the Array Controller is pretty simple too, although it acts as the Data
> Source and Delegate for the Collection View.
>
> Can anyone give me pointers for what I am screwing up? My web searches for
> this only return a meagre set of results which don’t help much.
>
> Kind regards,
> Arved
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