Question

我希望这不是一个愚蠢的问题，但我似乎无法弄清楚。我有一个包含许多条目的数组，我想在选择器中显示一定范围的选项（比如说从数组中的第二项到第五项）。我已经使用ForEach循环完成了此操作，但是我不知道如何指定要运行的循环的确切范围。这是下面的示例代码，可运行但显示整个数组。谢谢您的帮助

import SwiftUI

struct Plans: Identifiable {
    var id = UUID()
    var plan1: String
    var plan2: String
    var plan3: String
}

struct ContentView: View {
    @State private var picked = ""
    
    let goals = [
        Plans(plan1: "A", plan2: "B", plan3: "C"),
        Plans(plan1: "D", plan2: "D", plan3: "F"),
        Plans(plan1: "F", plan2: "G", plan3: "H"),
        Plans(plan1: "I", plan2: "J", plan3: "K"),
        Plans(plan1: "L", plan2: "M", plan3: "N"),
        Plans(plan1: "o", plan2: "P", plan3: "Q"),
        Plans(plan1: "R", plan2: "S", plan3: "T"),
        Plans(plan1: "U", plan2: "V", plan3: "W"),
        Plans(plan1: "X", plan2: "Y", plan3: "Z")
    ]
    
    
    var body: some View {
        NavigationView {
            Form {
                Picker(selection: self.$picked, label: Text("Pick your plan")) {
                    ForEach(goals, id:\.plan1)  { goal in
                        Text("\(goal.plan1)").tag(goal.plan1)
                    }
        
                }.id(UUID())
            }
        }
    }
}

Answer 1

您可以这样做：

ForEach(2..<goals.count, id: \.plan1) { goal in
    Text("\(goals[goal].plan1)")
        .tag(goals[goal])
}

这是您在swiftui中进行的操作。在ViewBuilders中不允许进行for-in循环... 例如。因为2 ... 5中的i在swiftui视图中不起作用，但这将：

ForEach(2...5, id: \.self) { goal in
    ...
}

如何在ForEach循环中选择特定范围以快速进行

1 个答案: