调用 objectWillChange.send（）会产生性能问题-解网

问：

我有一个具有嵌套对象结构的项目

Project -> Panels -> Layers

我有 SettingsView，我在其中更新任何这些结构的不同属性。

每次更新时，我都必须打电话才能立即查看 View 中的更改。如果我有少量对象，它可以正常工作并且不会产生性能问题。但是，如果对象数量增加，则会出现性能问题。objectWillChange.send()

我的代码示例如下：

class SelectedProjectHolder: ObservableObject {
    @Published var projects: [Project] = []
    @Published var selectedProject: Project? = nil
.....
    func updateTextLayerColor(for textLayer: TextLayer, newColor: Color) {
        guard let selectedProject = selectedProject else {
            return
        }
        
        for (panelIndex, panel) in selectedProject.panels.enumerated() {
            if let layerIndex = panel.textLayers.firstIndex(where: { $0.id == textLayer.id }) {
                selectedProject.panels[panelIndex].textLayers[layerIndex].color = newColor
                objectWillChange.send()
                return
            }
        }
    }
....
}

struct MainApp: App {
    
    let selectedProjectHolder = SelectedProjectHolder()
var body: some Scene {
        WindowGroup {
            ContentView(lastSaveTime: lastSaveTime)
                .environmentObject(selectedProjectHolder)
        }
        .commands {
            SidebarCommands()
        }
    }
}

// example of Panel view with passed data:
struct PanelView: View {
    @EnvironmentObject var selectedProjectHolder: SelectedProjectHolder
    @Binding var panel: Panel
...
}

我错过了什么，为什么它不显式调用就不起作用？objectWillChange.send()

有没有办法在我更改属性时立即查看更改而无需调用？objectWillChange.send()selectedProjectSelectedProjectHolder

iOS Swift macOS SwiftUI Core-Data

struct ProjectsView: View {
    @EnvironmentObject var projectsStore: ProjectsStore
    @State var selectedProject: Project? = nil

    // transform from the selection to the color
    // this is called every time the selection changes
    var textLayerColor: Color {
        guard let selectedProject = selectedProject else {
            return defaultColor
        }
        ...
        // find the color you want
        ...
        return newColor
    }

    var body: View {
    ...
        ForEach(projectsStore.projects) { project in
            // pass computed property into child View
            PanelView(color: textLayerColor) 
        ...

调用 objectWillChange.send（）会产生性能问题

Calling objectWillChange.send() produce performance issues

评论

评论

调用 objectWillChange.send（） 会产生性能问题

Calling objectWillChange.send() produce performance issues

评论

评论

调用 objectWillChange.send（）会产生性能问题