在 macOS 上的 SwiftUI 中将颜色从源拖放到目标

如何将颜色从源拖放到目的地并保留它？我目前的代码可以临时执行此操作（从源拖动时更改目标的颜色），但在鼠标松开时它会很快变回原样。那么，如何才能使颜色更改保持在鼠标悬停在特定单元格上的状态，并且能够在将来将鼠标悬停在该特定单元格上拖动时再次更改该单元格呢？我当前的代码基于here https://stackoverflow.com/questions/58900316/draggesture-on-a-vstack-with-lot-of-buttons-how-to-detect-when-the-drag-is-insi.

import SwiftUI

struct ContentView: View {
    var body: some View {
        HStack {
            ColorSource(color: .purple, color2: .orange)
            Spacer()
            ColorSource(color: .blue, color2: .pink)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}

struct DestinationDataKey: PreferenceKey {
    typealias Value = [DestinationData]

    static var defaultValue: [DestinationData] = []

    static func reduce(value: inout [DestinationData], nextValue: () -> [DestinationData]) {
        value.append(contentsOf: nextValue())
    }
}

struct DestinationData: Equatable {
    let destination: Int
    let frame: CGRect
}

struct DestinationDataSetter: View {
    let destination: Int

    var body: some View {
        GeometryReader { geometry in
            Rectangle()
                .fill(Color.clear)
                .preference(key: DestinationDataKey.self,
                            value: [DestinationData(destination: self.destination, frame: geometry.frame(in: .global))])
        }
    }
}

struct DestinationView: View {
    @Binding var active: Int
    let label: String
    let id: Int
    let color: Color

    var body: some View {
            Text(label).padding(10).background(self.active == id ? color : Color.green)
                .background(DestinationDataSetter(destination: id))
    }
}

struct ColorSource: View {
    @State var active = 0
    @State var destinations: [Int: CGRect] = [:]
    @State var color:Color
    @State var color2:Color
    @State var draggingFirstColor:Bool = false
    @State var draggingSecondColor:Bool = false

    var body: some View {
        VStack {

            Text("Drag From Here").padding().background(color)
                .gesture(DragGesture(minimumDistance: 0.1, coordinateSpace: .global)
                    .onChanged { value in
                        self.draggingFirstColor = true
                        self.active = 0
                        for (id, frame) in self.destinations {
                            if frame.contains(value.location) {
                                self.active = id
                            }
                        }
                    }
                    .onEnded { value in
                        // do something on drop
                        self.active = 0
                        self.draggingFirstColor = false

                    }
            )

            Text("Drag From Here").padding().background(color2)
                .gesture(DragGesture(minimumDistance: 0.1, coordinateSpace: .global)
                    .onChanged { value in
                        self.draggingSecondColor = true
                        self.active = 0
                        for (id, frame) in self.destinations {
                            if frame.contains(value.location) {
                                self.active = id
                            }
                        }
                    }
                    .onEnded { value in
                        // do something on drop
                        self.active = 0
                         self.draggingSecondColor = false
                    }
            )

            Divider()
            DestinationView(active: $active, label: "Drag Over Me", id: 1, color: (draggingFirstColor ? color : (draggingSecondColor ? color2 : Color.green)))
            DestinationView(active: $active, label: "Drag Over Me", id: 2, color: (draggingFirstColor ? color : (draggingSecondColor ? color2 : Color.green)))
            DestinationView(active: $active, label: "Drag Over Me", id: 3, color: (draggingFirstColor ? color : (draggingSecondColor ? color2 : Color.green)))
            DestinationView(active: $active, label: "Drag Over Me", id: 4, color: (draggingFirstColor ? color : (draggingSecondColor ? color2 : Color.green)))
        }.onPreferenceChange(DestinationDataKey.self) { preferences in
            for p in preferences {
                self.destinations[p.destination] = p.frame
            }
        }
    }
}

只是不要重置拖动颜色结束......或将其存储在某个地方（比如在模型中并在目的地中使用）

.onEnded { value in
    // do something on drop
    // self.active = 0
    // self.draggingFirstColor = false // same for second

}