获取 ScrollView 元素编号 SwiftUI

Question

我想根据单元格的编号更改ArticleListElementView。例如我在ScrollView 中有 10 个单元格，如果单元格编号为奇数，则显示 Rectangle()，如果单元格编号为偶数，则为 0 2 4 6 8，则隐藏 Rectangle()。所以我想我可以在ForEach() 中将cellNumber var 增加1，但它给了我一个错误。那么我该怎么做呢？

struct ArticleView: View {
@ObservedObject var service = ArticleService()
var cellNumber: Int = 0
var body: some View {
ScrollView(.vertical, showsIndicators: false) {
                        LazyVGrid(columns: columns, spacing:0) {
                            ForEach(service.articlePost, id: \.article_id) { post in
                                ArticleListElementView(articlePost: post)
                                    .onTapGesture {
                                        self.shown = true
                                        self.selectedArticle = post
                                    }
                                cellNumberRead()
                            }
                        }
                     }
                   }

func cellNumberRead() {
        cellNumber = cellNumber + 1
    }

struct ArticleListElementView: View {
    var articlePost: ArticlePost
    var body: some View {
        ZStack{
            Color("Background")
                .edgesIgnoringSafeArea(.all)
            HStack {
                //                if articlePost.cellNumber == I want to check cellNumber in here and draw a line else do not draw rectangle
                Rectangle()
                    .frame(width: 0.5, height: width)
        }

这是错误

Answer 1

您可以枚举数据并将索引直接注入行视图，例如

ForEach(Array(service.articlePost.enumerated()), id: \.1.article_id) { i, post in
    ArticleListElementView(articlePost: post, cellNumber: i)   // << here !!

现在根据需要在 ArticleListElementView 中使用

struct ArticleListElementView: View {
    var articlePost: ArticlePost
    var cellNumber: Int

    var body: some View {
        ZStack{
            Color("Background")
                .edgesIgnoringSafeArea(.all)
            HStack {
                if cellNumber % 2 == 0 {
                   // .. your code
                } else {
                   // .. another case
                }