ASCollectionFlexLayout
ASCollectionFlexLayout is a custom collection layout that allows to use Texture layout specs in ASCollectionNode.
Usage
Creating a layout
let layout = ASCollectionFlexLayout()
layout.layoutProvider = self
let collectionNode = ASCollectionNode(collectionViewLayout: layout)
If you don't specify the layoutProvider
, it will use a ASStackLayout
as default.
Implementing ASCollectionFlexLayoutProvider protocol
There are two kind of layout specs in ASCollectionFlexLayout:
- A layout for sections
- A Layout for items in a section
You can optionally provide each layout specs by implementing ASCollectionFlexLayoutProvider
protocol.
protocol ASCollectionFlexLayoutProvider {
/// A layout spec for sections. The default layout spec is a stretched stack layout with no spacing.
func flexLayout(_ layout: ASCollectionFlexLayout, layoutSpecThatFits constrainedSize: ASSizeRange, sectionElements: [ASLayoutElement]) -> ASLayoutSpec?
/// A layout spec for items in a section. The default layout spec is a flex-wrapping stack with no spacing.
func flexLayout(_ layout: ASCollectionFlexLayout, layoutSpecThatFits constrainedSize: ASSizeRange, forSectionAt section: Int, itemElements: [ASLayoutElement]) -> ASLayoutSpec?
}
For example:
extension MyViewController: ASCollectionFlexLayoutProvider {
func flexLayout(_ layout: ASCollectionFlexLayout, layoutSpecThatFits constrainedSize: ASSizeRange, sectionElements: [ASLayoutElement]) -> ASLayoutSpec? {
return ASStackLayoutSpec(
direction: .vertical,
spacing: 20,
justifyContent: .start,
alignItems: .start,
children: sectionElements
)
}
func flexLayout(_ layout: ASCollectionFlexLayout, layoutSpecThatFits constrainedSize: ASSizeRange, forSectionAt section: Int, itemElements: [ASLayoutElement]) -> ASLayoutSpec? {
return ASStackLayoutSpec(
direction: .horizontal,
spacing: 10,
justifyContent: .start,
alignItems: .start,
flexWrap: .wrap,
alignContent: .start,
lineSpacing: 10,
children: itemElements
)
}
}
Using the default layout
You can modify the default layout to apply layout without implementing ASCollectionFlexLayoutProvider
protocol.
let layout = ASCollectionFlexLayout()
layout.defaultSectionLayout.alignItems = .center
layout.defaultItemLayout.direction = .vertical
layout.defaultItemLayout.alignItems = .stretch
Also you can directly refer to the default layout in the ASCollectionFlexLayoutProvider
protocol implementation.
func flexLayout(_ layout: ASCollectionFlexLayout, layoutSpecThatFits constrainedSize: ASSizeRange, forSectionAt section: Int, itemElements: [ASLayoutElement]) -> ASLayoutSpec? {
let insets = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 20)
return ASInsetLayoutSpec(insets: insets, child: layout.defaultItemLayout)
}
License
ASCollectionFlexLayout is under MIT license. See the LICENSE for more info.