如何在 SwiftUI 中更改数组索引

Question

我有一个调用数组索引来填充页面的页面视图。当发生某些事情时，我想增加索引以更新页面的内容。在此代码示例中，我在按下按钮时发生了这种情况。在我的真实应用程序中，我希望在计时器达到 0 时发生这种情况，但我怀疑如果我能弄清楚如何让这个按钮按下版本工作，我可以将其推断到我的真实用例中。以下是供您查看的简单代码：

import SwiftUI

struct LanguageStruct: Identifiable {
    var id = UUID()
    var groupTitle: String
    var title: String
    var subTitle: String
    var image: String
}

var progLanguages = [
    LanguageStruct(groupTitle: "Java", title: "Lame Langauge", subTitle: "Bad GUI", image: "Push-ups Wide"),
    LanguageStruct(groupTitle: "SwiftUI", title: "Nice and New", subTitle: "Better than Swift but incomplete", image: "Sit-ups")
]

struct Playground_arrays: View {
    
    @State private var index = 0
    var programming: LanguageStruct
    
    var body: some View {
        VStack {
            Text(programming.groupTitle)
            Text (programming.subTitle)
            Image(programming.image)
            
            Button(action:{
                //actions go here
                if index < 2{
                    index += 1
                    
                }else{
                    index = 0
                }
            }, label:{
                Text("Change Index")
                    .fontWeight(.semibold)
            })
            .buttonStyle(PrimaryButtonStyle(buttonColor: "PositiveGreen"))
        }
    }
}

struct Playground_arrays_Previews: PreviewProvider {
    static var previews: some View {
        Playground_arrays(programming: progLanguages[0])
            .previewDevice("iPhone 12 mini")
    }
}

有人可以帮我弄清楚如何在按下按钮时更新数组的索引，以便我可以更新页面内容吗？这似乎真的应该像上面的index var 计数器并将其放在programing: progLanguages[index] 字符串或其他东西一样简单，但我一生都无法弄清楚如何让它工作:(

Answer 1

只需将 programming 作为动态 getter：

struct Playground_arrays: View {
    @State private var index = 0

    var programming: LanguageStruct {
        progLanguages[index]
    }
    
    var body: some View {
        VStack {
            Text(programming.groupTitle)
            Text (programming.subTitle)
            Image(programming.image)
            
            Button(action:{
                //actions go here
                if index < progLanguages.count - 1 {
                    index += 1
                } else {
                    index = 0
                }
            }, label:{
                Text("Change Index")
                    .fontWeight(.semibold)
            })
            .buttonStyle(PrimaryButtonStyle(buttonColor: "PositiveGreen"))
        }
    }
}