DatePicker 在 SwiftUI 中使用时间间隔

Question

我想在 SwiftUI 中使用 DatePicker，它按预期工作正常。我想添加一个时间间隔，如解释：UIDatePicker 15 Minute Increments Swift

DatePicker("Please enter a time", selection: $wakeUp, displayedComponents: .hourAndMinute)

在 SwifUI 中是否有修改器？

Answer 1

不完全是 SwiftUI 解决方案，但比现有答案简单得多。将其附加到包含选择器的主体视图

.onAppear {
    UIDatePicker.appearance().minuteInterval = 5
}

一个缺点是这将适用于视图中的所有选择器，并可能影响应用程序中其他视图中的选择器，但您始终可以在这些视图中执行相同的操作（将分钟间隔设置回 1）。

Answer 2

我不相信有一个修饰符。但是，可以通过使用 UIViewRepresentable 包装 UIDatePicker 来“自己做”：

此代码的基本结构基于UIKit教程。

struct MyDatePicker: UIViewRepresentable {

    @Binding var selection: Date
    let minuteInterval: Int
    let displayedComponents: DatePickerComponents

    func makeCoordinator() -> Coordinator {
        return Coordinator(self)
    }

    func makeUIView(context: UIViewRepresentableContext<MyDatePicker>) -> UIDatePicker {
        let picker = UIDatePicker()
        // listen to changes coming from the date picker, and use them to update the state variable
        picker.addTarget(context.coordinator, action: #selector(Coordinator.dateChanged), for: .valueChanged)
        return picker
    }

    func updateUIView(_ picker: UIDatePicker, context: UIViewRepresentableContext<MyDatePicker>) {
        picker.minuteInterval = minuteInterval
        picker.date = selection

        switch displayedComponents {
        case .hourAndMinute:
            picker.datePickerMode = .time
        case .date:
            picker.datePickerMode = .date
        case [.hourAndMinute, .date]:
            picker.datePickerMode = .dateAndTime
        default:
            break
        }
    }

    class Coordinator {
        let datePicker: MyDatePicker
        init(_ datePicker: MyDatePicker) {
            self.datePicker = datePicker
        }

        @objc func dateChanged(_ sender: UIDatePicker) {
            datePicker.selection = sender.date
        }
    }
}

struct DatePickerDemo: View {
    @State var wakeUp: Date = Date()
    @State var minterval: Int = 1

    var body: some View {
        VStack {
            Stepper(value: $minterval) {
                Text("Minute interval: \(minterval)")
            }
            MyDatePicker(selection: $wakeUp, minuteInterval: minterval, displayedComponents: .hourAndMinute)
            Text("\(wakeUp)")
        }
    }
}

struct DatePickerDemo_Previews: PreviewProvider {
    static var previews: some View {
        DatePickerDemo()
    }
}