swiftui - 在 macOS 上的 SwiftUI 中将颜色从源拖放到目标

Question

如何将颜色从来源拖放到目的地并保留下来？我目前有代码可以临时执行此操作(从源拖动时更改目标颜色)，但它会在鼠标抬起时迅速变回。那么，我怎样才能让颜色变化保持在鼠标悬停在特定单元格上，并且能够在以后将鼠标悬停在该特定单元格上时再次更改该单元格？我当前的代码基于 here .

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
            }
        }
    }
}

Answer 1

只是不要在结束时重置拖动颜色...或将其存储在某个地方(比如在模型中并在目标中使用)

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

}