Question

我正在开发一个应用程序，该应用程序要根据用户选择显示数据的年份来显示数据。

使用ForEach时，我目前无法最终确定选择-当我手动编写数据时，它可以完美地工作。我想要的是更改选定年份的颜色，否则将其保持灰色。

我认为从State更改为ObservedObject是可以的，但是没有用。当前，当我单击年份时，它被选中，但其他未被选中（在某种意义上，它们保持黑色而不是灰色）–当我打印ObservedObject值而不是年份时值，每个值都不同。

import SwiftUI

struct YearSelection: View {
    var body: some View {
        ScrollView(.horizontal, showsIndicators: false) {
            HStack(spacing: 34) {
                ForEach(YearData) { item in
                    YearSelectionList( year: item)
                }
                Spacer()
            }
        }.padding(.bottom)
    }
}

struct YearSelectionList: View {
    var year: Year
    @ObservedObject var selectedYear = SelectedYear()
    var body: some View {
        
        Button(action: {selectedYear.selectedYear = year.year}, label: {
                Text(year.year).foregroundColor(selectedYear.selectedYear == year.year ? Color.black : Color.gray)
            })

    }
}

class SelectedYear: ObservableObject {
    @Published var selectedYear = "2021"
}

struct Year: Identifiable {
    var id = UUID()
    var type: String
    var year: String
}

let YearData = [
    Year(type: "1", year: "2021"),
    Year(type: "1", year: "2017"),
    Year(type: "1", year: "2013"),
    Year(type: "1", year: "2010"),
    Year(type: "1", year: "2006"),
    Year(type: "1", year: "2002")
]

谢谢您的帮助！

Answer 1

    import SwiftUI

struct ContentView: View {
    var body: some View {
        
        YearSelection()  
    }
}


struct Year: Identifiable
{
    var id = UUID()
    var selected: Bool
    var year: String
}


var YearData = [
    Year(selected: false, year: "2021"),
    Year(selected: false, year: "2017"),
    Year(selected: false, year: "2013"),
    Year(selected: false, year: "2010"),
    Year(selected: false, year: "2006"),
    Year(selected: false, year: "2002")
]


class SelectedYear: ObservableObject
{
    @Published var selectedYear = YearData
}


struct YearSelection: View
{
    @ObservedObject var selectedYear = SelectedYear()
    
    var body: some View
    {
        
        
        
        ScrollView(.horizontal, showsIndicators: false)
        {
            HStack(spacing: 34)
            {
                
                
                ForEach(selectedYear.selectedYear.indices) { index in
                    

                    
                    
 
                    Button(action: {

                        if selectedYear.selectedYear.count > 0
                        {
                            for i in 0 ... selectedYear.selectedYear.count - 1
                            {
                                selectedYear.selectedYear[i].selected = false
                            }
                        }

                        selectedYear.selectedYear[index].selected.toggle()
                        
                        
                    }){
                        
                        Text(selectedYear.selectedYear[index].year).foregroundColor(selectedYear.selectedYear[index].selected ? Color.red : Color.gray)
                        
                    }
  
                    
                    
                }
                
                
                Spacer()
            }
        }
        .padding(.bottom)
        
        
        
    }
}

版本2.0.0：

    import SwiftUI

struct ContentView: View {
    var body: some View {
        
        YearSelection()
    }
}


struct Year: Identifiable
{
    var id = UUID()
    var selected: Bool
    var year: String
}


var YearData = [
    Year(selected: false, year: "2021"),
    Year(selected: false, year: "2017"),
    Year(selected: false, year: "2013"),
    Year(selected: false, year: "2010"),
    Year(selected: false, year: "2006"),
    Year(selected: false, year: "2005"),
    Year(selected: false, year: "2004"),
    Year(selected: false, year: "2003"),
    Year(selected: false, year: "2002")
]


class SelectedYear: ObservableObject
{
    @Published var selectedYear = YearData
}


struct YearSelection: View
{
    
    @ObservedObject var selectedYear = SelectedYear()
    @State var previousSelectedYear: Int = -1

    var body: some View
    {
        

        ScrollView(.horizontal, showsIndicators: false)
        {
            HStack(spacing: 34)
            {

                ForEach(selectedYear.selectedYear.indices) { index in
                    
                    Button(action: {

                        if (previousSelectedYear != -1) { selectedYear.selectedYear[previousSelectedYear].selected = false }
                        selectedYear.selectedYear[index].selected.toggle()
                        previousSelectedYear = index
                        
                    }){ Text(selectedYear.selectedYear[index].year).foregroundColor(selectedYear.selectedYear[index].selected ? Color.red : Color.gray) }
  
                }

            }
            
        }

        
        
        
    }
}

ForEach中的SwiftUI按钮不会更改前景色

1 个答案: