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4、用List显示多层级列表

我们可以用展开收起的列表来展示层级。

Getting ready​

首先，创建一个新项目：ExpandingLists

How to do it…​

  1. 首先，定义一个多层数据结构
struct Backpack: Identifiable {
    let id = UUID()
    let name: String
    let icon: String
    var content: [Backpack]?
}
  1. 准备数据
let dollar = Backpack(name: "Dollar", icon: "dollarsign.circle")
let yen = Backpack(name: "Yen",icon: "yensign.circle")
let currencies = Backpack(name: "Currencies", icon: "coloncurrencysign.circle", content: [dollar, yen])

let pencil = Backpack(name: "Pencil",icon: "pencil.circle")
let hammer = Backpack(name: "Hammer",icon: "hammer")
let paperClip = Backpack(name: "Paperclip",icon: "paperclip")
let glass = Backpack(name: "Magnifying glass", icon: "magnifyingglass")
let bin  = Backpack(name: "Bin", icon: "arrow.up.bin", content: [paperClip, glass])
let tools = Backpack(name: "Tools", icon: "folder", content: [pencil, hammer,bin])
  1. 在contentView中定义数据
struct ContentView: View {
    let bagContents = [currencies,tools]
}
  1. 显示数据
var body: some View {
    List(bagContents, children: \.content){ row in
        Image(systemName: row.icon)
        Text(row.name)
    }
}

最终结果:

Simulator Screen Shot - iPhone 12 - 2021-12-28 at 23.57.21

How it works…​

首先我们定义了Backpack，拥有嵌套结构，能表示多个层级。

我们显示List时，指定children为content字段。

List(bagContents, children: \.content){ row in
    Image(systemName: row.icon)
    Text(row.name)
}