如何使用UICollectionViewCompositionalLayout创建类似图像的集合视图

问题描述

几天以来，我一直无法弄清楚如何使用UICollectionViewCompositionalLayout来制作屏幕截图中的集合视图。有人可以帮忙吗？ Image!!!!

解决方法

您可以通过将两个垂直NSCollectionLayoutGroup组合成一个水平组来实现此布局。每个垂直组由两个iten（一个大和另一个小）组成。

final class CustomLayout {



class func create() -> UICollectionViewCompositionalLayout{
    
    //Obs: The size of each element is relative to his parent.
    //NSCollectionLayoutItem < NSCollectionLayoutGroup < NSCollectionLayoutSection < UICollectionViewCompositionalLayout
    
    
    
    //Defines the margin
    let margin: CGFloat = 5
    //Defines the space between the cells
    let contentInsests: CGFloat = 8

    
    // Create the big item that is 60% of your parent's height
    let bigItem = NSCollectionLayoutItem(
        layoutSize: NSCollectionLayoutSize(
            widthDimension: .fractionalWidth(1.0),heightDimension: .fractionalHeight(0.60)))
    
    bigItem.contentInsets = NSDirectionalEdgeInsets(
        top: contentInsests,leading: contentInsests,bottom: contentInsests,trailing: contentInsests)
    
    // Create the small item that is 40% of your parent's height
    let smallItem = NSCollectionLayoutItem(
        layoutSize: NSCollectionLayoutSize(
            widthDimension: .fractionalWidth(1.0),heightDimension: .fractionalHeight(0.40)))
    
    smallItem.contentInsets = NSDirectionalEdgeInsets(
        top: contentInsests,trailing: contentInsests)
    

    //Here we Combine the two itens in a vertical group
    let group1 = NSCollectionLayoutGroup.vertical(
        layoutSize: NSCollectionLayoutSize(
            widthDimension: .fractionalWidth(0.5),heightDimension: .fractionalHeight(1.0)),subitems: [bigItem,smallItem])
    
    //Here we do the same reversing the order of the itens
    let group1Reversed = NSCollectionLayoutGroup.vertical(
        layoutSize: NSCollectionLayoutSize(
            widthDimension: .fractionalWidth(0.5),subitems: [smallItem,bigItem])
    
    
    //here we combine both in a nested group making the layout like in the image.
    //In this example we are making a custom layout with two "Image layout" per screen,so
   // We define his height as 0.5% of his parent's height. You can change it for your preference.
    let nestedGroup = NSCollectionLayoutGroup.horizontal(
        layoutSize: NSCollectionLayoutSize(
            widthDimension: .fractionalWidth(1.0),heightDimension: .fractionalHeight(0.5)),subitems: [
          group1,group1Reversed
        ]
    )
    
    
    //Here is our main group with two nested group
    let mainGroup = NSCollectionLayoutGroup.vertical(
        layoutSize: NSCollectionLayoutSize(
            widthDimension: .fractionalWidth(1.0),subitems: [
          nestedGroup,nestedGroup
        ]
    )
    
    
    
    let section = NSCollectionLayoutSection(group: mainGroup)
    
    
    section.contentInsets = NSDirectionalEdgeInsets(
        top: 0,leading: margin,bottom: 0,trailing: margin)
    
    let configuration = UICollectionViewCompositionalLayoutConfiguration()
    configuration.scrollDirection = .vertical
    let layout = UICollectionViewCompositionalLayout(section: section)
    layout.configuration = configuration
    return layout
}}

Example