ios - 基于 SWIFTUI 中的按钮操作和选定索引的滚动视图

Question

我想在 SwiftUI 中使用 Button 操作制作滚动视图

为此，我使用 ScrollViewReader 编写了以下代码，但它给了我一个错误。

使用未解析的标识符“ScrollViewReader”给出错误

找到我的代码如下。

任何人都对这个问题有一些想法。

预期输出如下图

struct ContentView: View {

@State var days = [CalendarDay]()
@State var selectedDay: Int = 0

var body: some View {
    ScrollViewReader { scrollProxy in
        HStack {
            Button(action: {
                if selectedDay > 0 {
                    for j in days.indices { days[j].isToday = false }
                    days[selectedDay-1].isToday = true
                    selectedDay -= 1
                    withAnimation { scrollProxy.scrollTo(selectedDay) }
                }
            }) {
                Image(systemName: "chevron.left.circle.fill")
            }
            ZStack{
                VStack {
                    ScrollView(.horizontal, showsIndicators: false){
                        HStack(spacing: 20) {
                            ForEach(days.indices, id: \.self) { i in
                                CalendarView(
                                    number: days[i].number,
                                    days: days[i].weekday,
                                    color: days[i].isToday ? #colorLiteral(red: 0.9060331583, green: 0.2547450066, blue: 0.3359550834, alpha: 1) : #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1),
                                    textcolor: days[i].isToday ? #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1) : #colorLiteral(red: 0, green: 0, blue: 0, alpha: 1)
                                ).onTapGesture {
                                    selectedDay = i
                                    for j in days.indices {
                                        if j == i {
                                            days[i].isToday = true
                                        } else {
                                            days[j].isToday = false
                                        }
                                    }
                                }
                            }
                            
                        }
                        .padding(.leading,10)
                        .padding(.bottom, 10)
                        .shadow(radius: 3, x: 3, y: 3)
                    }
                }
            }
            Button(action: {
                if selectedDay < days.count-1 {
                    for j in days.indices { days[j].isToday = false }
                    days[selectedDay+1].isToday = true
                    selectedDay += 1
                    withAnimation { scrollProxy.scrollTo(selectedDay) }
                }
            }) {
                Image(systemName: "chevron.right.circle.fill")
            }
        }
    }
    .onAppear {
        getCurrentWeekdays()
    }
}
    
    func getCurrentWeekdays() {
        /// from https://stackoverflow.com/a/62355272/14351818
        let dateComponents = Calendar(identifier: .gregorian).dateComponents([.yearForWeekOfYear, .weekOfYear], from: Date())
        let startOfWeek = Calendar(identifier: .gregorian).date(from: dateComponents)!
        let startOfWeekNoon = Calendar(identifier: .gregorian).date(bySettingHour: 12, minute: 0, second: 0, of: startOfWeek)!
        
        days = (0...6).map {
            let calendar = Calendar(identifier: .gregorian)
            let date = calendar.date(byAdding: .day, value: $0, to: startOfWeekNoon)!
            
            let numberDateFormatter = DateFormatter()
            numberDateFormatter.dateFormat = "d"
            let number = numberDateFormatter.string(from: date)
            
            let weekdayDateFormatter = DateFormatter()
            weekdayDateFormatter.dateFormat = "E"
            let weekday = weekdayDateFormatter.string(from: date)
            
            let calendarDay = CalendarDay(
                number: number,
                weekday: weekday,
                isToday: calendar.component(.day, from: Date()) == calendar.component(.day, from: date)
            )
            //  <--- here --->
            if calendar.component(.day, from: Date()) == calendar.component(.day, from: date) {
                selectedDay = $0
            }
            
            return calendarDay
        }
        
    }
}

标签： iosarraysswiftscrollview