SwiftUI：如何创建自定义UIDatePicker [英] SwiftUI: how to create custom UIDatePicker

问题描述

我成功在SwifUI中创建了UIDatePicker，但是当我在选择器中更改日期轮时，日期值未更新，这是我的代码：

I succeeded to create UIDatePicker inside SwifUI, but when I change the date wheel in picker the date value not update, here is my code:

    struct DatePicker: UIViewRepresentable {
    @Binding var date: Date

    func makeUIView(context: Context) -> UIDatePicker {
        let view = UIDatePicker()
        view.datePickerMode = .date
        return view
    }
    func updateUIView(_ uiView: UIDatePicker, context: Context) {
        uiView.date = date
    }
}

然后我从这样的视图调用它：

Then I call it from the view like this:

struct SwiftUIView: View {
  @State var date = Date()
    var body: some View {
      DatePicker(date: self.$date)
  }
}

推荐答案

这里是可行的方法。使用Xcode 11.2 / iOS 13.2测试

Here is possible approach. Tested with Xcode 11.2 / iOS 13.2

struct DatePicker: UIViewRepresentable {
    @Binding var date: Date

    private let datePicker = UIDatePicker()

    func makeUIView(context: Context) -> UIDatePicker {
        datePicker.datePickerMode = .date
        datePicker.addTarget(context.coordinator, action: #selector(Coordinator.changed(_:)), for: .valueChanged)
        return datePicker
    }

    func updateUIView(_ uiView: UIDatePicker, context: Context) {
        datePicker.date = date
    }

    func makeCoordinator() -> DatePicker.Coordinator {
        Coordinator(date: $date)
    }

    class Coordinator: NSObject {
        private let date: Binding<Date>

        init(date: Binding<Date>) {
            self.date = date
        }

        @objc func changed(_ sender: UIDatePicker) {
            self.date.wrappedValue = sender.date
        }
    }
}

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