Dynamic height for HorizontalBlueprintLayout

[zishanj]

With UICollectionViewFlowLayout I can set the height dynamic which adjust itself according to the underlying content by setting height in estimatedItemSize to 1 and then overriding systemLayoutSizeFitting in cell and setting height again to 1. This makes the height auto-adjusted according to its content. In Blueprints, it seems to be overriding it and I am no longer able to make it dynamic. I am using single row layout with multiple items.

[zenangst]

@zishanj Blueprints does not currently support dynamic widths or heights. We would love to add it so if you are up for me, make a PR and we will gladly review it :) I don’t think it would be to hard, just make an exception for estimated heights and check the cell for the system layout size fitting method, I might be wrong but that is my initial gut feeling.

[zenangst]

Did a quick search and found this: https://link.medium.com/oj69yvGzoY
Might be a good starting point for the implementation.

[zishanj]

I wonder why the usual code does not work any more with this lib like I mentioned in my main comment. It was simple with that by setting height to 1.

[zenangst]

I think it has to do with how we explicitly set the size of the items. We should revisit this and reimplement it in a way that works with dynamic size.

[zishanj]

Anxiously waiting for this fix.

[zenangst]

@zishanj I've started investigating how this could be implemented now, no ETA and no promises. Will post an updated when I have something more substantial to convey.

[christoff-1992]

@zishanj I've started investigating how this could be implemented now, no ETA and no promises. Will post an updated when I have something more substantial to convey.

@zenangst - I think I still have the work for this in the work I was looking at for the invalidation context. I believe you already have access to the repo, if not send us a message on slack. I hadn't completed it and abandoned the update after the changes where made in this repo for the invalidation context. However the changes meant all layouts would support dynamic sizes.

https://github.com/christoff-1992/Blueprints/blob/Feature/Horizontal-layout/Sources/HorizontalBlueprintLayout.swift

[zenangst]

@zishanj I have a branch that you can try out here feature/support-for-dynamic-sizes.
Take it for a spin and see how it works for you, I've done some testing using unit tests but I have yet to try it in a project (for the lack of time).

I hope this branch takes us closer to the goal.

[zishanj]

I have tried this branch today and the result was same. estimatedItemSize and systemLayoutSizeFitting does not makes it dynamic by setting height to 1.

[zenangst]

@zishanj Have you implemented preferredLayoutAttributesFitting on your cells?

[zishanj]

Previously with UICollectionView I have been using:
layout.estimatedItemSize = CGSize(width: 180, height: 1)
and in cell

override func systemLayoutSizeFitting(_ targetSize: CGSize) -> CGSize {
        return contentView.systemLayoutSizeFitting(CGSize(width: 180, height: 1))
}

This makes the height dynamic with fixed width. With blueprint I have just replaced layout.estimatedSize to be used in its init:

let layout = HorizontalBlueprintLayout(
            itemsPerColumn: 1,
            itemSize: CGSize(width: 180, height: 1),
            minimumInteritemSpacing: 10,
            minimumLineSpacing: 10
)

and using same systemLayoutSizeFitting in cell. But it didn't work!

[zenangst]

@zishanj mind setting up a demo project that we can have access to? That would definitely speed things up.

Did you try the preferred layout attributes approach?
You can check the setup in one of the tests on the new branch.

[zenangst]

Also, itemSize is not the same as estimated item size, try to set that explicitly after you create the layout. (We can definitely improve the init methods here).

[zishanj]

I tried in this way now without any luck:
layout.estimatedItemSize =UICollectionViewFlowLayout.automaticSize
then in cell I have only explicitly mentioned the width expecting the height to get auto adjust:

override func preferredLayoutAttributesFitting(_ layoutAttributes: UICollectionViewLayoutAttributes) -> UICollectionViewLayoutAttributes {
        let attributes = super.preferredLayoutAttributesFitting(layoutAttributes)
        attributes.size.width = 180
        return attributes
    }

[zishanj]

I guess height in this init:

let layout = HorizontalBlueprintLayout(
            itemsPerColumn: 1,
            itemSize: CGSize(width: 180, height: 1),
            minimumInteritemSpacing: 10,
            minimumLineSpacing: 10
        )

is overriding the dynamic height in cell. When I debug the view hierarchy it still gives me height = 1.