swift - 如何在 SwiftUI 中添加自定义容器视图

Question

我很好奇您是否可以在 SwiftUI 中创建自定义容器视图。我知道您可以创建自定义内容视图，例如Text()，但不确定您是否可以复制 say 的功能HStack { }

类似于：

HGrid {
    Text("Lorem ipsum")
    Text("Lorem ipsum")
}

然后，自定义容器视图（aka HGrid）将Spacer()在每个添加的组件之间添加。本质上，例如，将其转换为：

HStack {
    Text("Lorem ipsum")
    Spacer()
    Text("Lorem ipsum")
}

Answer 1

SwiftUI用ViewBuilder @functionBuilder

struct HGrid <Content: View>: View {
    init(@ViewBuilder builder: () -> Content) {
        let content = builder()
        ...
    }
}

也可以看看

• https://forums.swift.org/t/function-builders/25167
• https://github.com/apple/swift-evolution/pull/1046

Answer 2

如果我们尽量保持简单并只做一件事，可以提出两种选择：

import SwiftUI
// Via custom containers
struct HGrid<Content: View>: View {
    let C1: Content
    let C2: Content

    var body: some View {
        HStack {
            C1
            Spacer()
            C2
        }
    }
}
// Via View composition
struct HGridComposition: View {
    var text1: String
    var text2: String

    var body: some View {
        HStack {
            Text(text1)
            Spacer()
            Text(text2)
        }
    }
}


struct ContentView: View {
    var body: some View {
        VStack {
            Text("Composed from Views").font(.headline)
        HGrid(C1: Text("First"), C2: Text("Second"))
            Divider()
            Text("Composed from texts (String)").font(.headline)
        HGridComposition(text1: "Text One", text2: "Text Two")
        }
        .padding([.leading, .trailing])
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}