SwiftUI - 动画视图扩展（显示/隐藏）

我有一个View其中包含一个HStack and a DatePicker。当您点击HStack, the DatePicker显示/隐藏。我想为这个动作设置动画，就像 iOS 日历的新事件视图中开始和结束行的动画一样。

struct TimePicker: View {
    @Binding var startTime: Date
    
    @State private var isDatePickerVisible: Bool = false
    
    var body: some View {
        VStack(alignment: .center) {
            HStack {
                ListItemView(icon: "start-time",
                             leadingText: "Start Time",
                             trailingText: startTime.stringTime())
            }
            .onTapGesture {
                withAnimation {
                    self.isDatePickerVisible.toggle()
                }
            }
            
            Group {
                if isDatePickerVisible {
                    DatePicker("", selection: $startTime, displayedComponents: [.hourAndMinute])
                        .datePickerStyle(WheelDatePickerStyle())
                }
            }
            .background(Color.red)

            .modifier(AnimatingCellHeight(height: isDatePickerVisible ? 300 : 0))
        }
    }
}

我使用了以下代码来制作动画。几乎可以用了。唯一的问题是HStack跳跃。我无法修复它。

https://stackoverflow.com/a/60873883/8292178 https://stackoverflow.com/a/60873883/8292178

struct AnimatingCellHeight: AnimatableModifier {
    var height: CGFloat = 0

    var animatableData: CGFloat {
        get { height }
        set { height = newValue }
    }

    func body(content: Content) -> some View {
        content.frame(height: height)
    }
}

如何解决这个问题？如何设置动画的可见性DatePicker?

很简单，不需要额外的ViewModifier

    struct TimePicker: View {
        @Binding var startTime: Date
        @State private var isDatePickerVisible: Bool = false
        
        var body: some View {
            VStack(alignment: .center) {
                HStack {
                    ListItemView(icon: "start-time"
                         , leadingText: "Start Time"
                         , trailingText: startTime.stringTime())
                }.onTapGesture {
                    isDatePickerVisible.toggle()
                }
                
                if isDatePickerVisible {
                    DatePicker(""
                         , selection: $model.startTime
                         , displayedComponents: [.hourAndMinute]
                    ).datePickerStyle(WheelDatePickerStyle())
                }
            }.animation(.spring())
        }
    }