如何在SwiftUI中判断VoiceOver等辅助技术是否启用？

直接调用UIKit的UIAccessibility API在SwiftUI里完全可行，但如果想要更贴合SwiftUI的响应式风格，推荐以下两种实现方式：

方式一：自定义@Environment变量（推荐） #

通过自定义环境键，可以把辅助技术状态转化为SwiftUI环境变量，在视图层级中轻松访问，且状态变化时视图会自动更新。

1. 定义环境键 #

import SwiftUI
import UIKit

private struct VoiceOverEnabledKey: EnvironmentKey {
    static let defaultValue: Bool = UIAccessibility.isVoiceOverRunning
}

extension EnvironmentValues {
    var isVoiceOverEnabled: Bool {
        get { self[VoiceOverEnabledKey.self] }
        set { self[VoiceOverEnabledKey.self] = newValue }
    }
}

2. 监听状态变化并同步到环境 #

在App入口或根视图中添加监听，实时更新状态：

@main
struct YourApp: App {
    @State private var isVoiceOverEnabled = UIAccessibility.isVoiceOverRunning
    
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environment(\.isVoiceOverEnabled, isVoiceOverEnabled)
                .onAppear {
                    NotificationCenter.default.addObserver(
                        forName: UIAccessibility.voiceOverStatusDidChangeNotification,
                        object: nil,
                        queue: .main
                    ) { _ in
                        isVoiceOverEnabled = UIAccessibility.isVoiceOverRunning
                    }
                }
        }
    }
}

3. 在视图中使用 #

struct ContentView: View {
    @Environment(\.isVoiceOverEnabled) private var isVoiceOverEnabled
    
    var body: some View {
        Text(isVoiceOverEnabled ? "VoiceOver已启用" : "VoiceOver未启用")
    }
}

方式二：用ObservableObject管理状态 #

如果需要在多视图或ViewModel间共享状态，可以用ObservableObject封装：

import SwiftUI
import UIKit

class AccessibilityStatusManager: ObservableObject {
    @Published var isVoiceOverEnabled = UIAccessibility.isVoiceOverRunning
    
    init() {
        NotificationCenter.default.addObserver(
            forName: UIAccessibility.voiceOverStatusDidChangeNotification,
            object: nil,
            queue: .main
        ) { [weak self] _ in
            self?.isVoiceOverEnabled = UIAccessibility.isVoiceOverRunning
        }
    }
}

// 视图中调用示例
struct ContentView: View {
    @StateObject private var accessibilityManager = AccessibilityStatusManager()
    
    var body: some View {
        Text(accessibilityManager.isVoiceOverEnabled ? "VoiceOver已启用" : "VoiceOver未启用")
    }
}

补充说明 #

• 针对Switch Control、Zoom等其他辅助技术，可复用类似逻辑：监听对应通知（如UIAccessibility.switchControlStatusDidChangeNotification），调用UIAccessibility.isSwitchControlRunning等属性获取状态。
• 直接使用UIKit的UIAccessibility API本身并无问题，上述方案只是将其适配为SwiftUI的响应式风格，让状态变化自动驱动视图更新。

内容的提问来源于stack exchange，提问作者Jacob Jidell