如何确认 AppDelegate 的 ObservableObject？

Question

我试图在 macOS AppDelegate 中观察一个值，但出现错误

ContentView.swift:14:6: Generic struct 'ObservedObject' requires that 'NSApplicationDelegate?' conform to 'ObservableObject'

当我尝试使用 as! ObservedObject 将对象转换为 ObservedObject 时，出现另一个错误

ContentView.swift:14:6: Generic struct 'ObservedObject' requires that 'ObservedObject' conform to 'ObservableObject'

在 AppDelegate.swift 文件中

import Cocoa
import SwiftUI
import Combine

@NSApplicationMain
class AppDelegate: NSObject, ObservableObject, NSApplicationDelegate  {
    var isFocused = true
    
    // Other code app life-cycle functions
}

在 ContentView.swift 文件中

import SwiftUI
import Combine

struct ContentView: View {
    @ObservedObject var appDelegate = NSApplication.shared.delegate
    
    // Other UI code
}

Answer 1

这看起来像是概念的混合。我建议避免这样...而是创建显式可观察对象 class。

如下图（草图）

class AppState: ObservableObject {
  @Published var isFocused = true
}

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate  {
    var appState = AppState()
    
    // Other code app life-cycle functions

     // in place where ContentView is created
     ...
     ContentView().environmentObject(self.appState)
     ...
}

并在 ContentView 中使用它

struct ContentView: View {
    @EnvironmentObject var appState: AppState
    
    // Other UI code

    var body: some View {
       // .. use self.appState.isFocused where needed
    }
}

如何确认 AppDelegate 的 ObservableObject？

How to confirm ObservableObject for an AppDelegate?

macos

swiftui

combine