点击NavigationLink时App冻结、CPU占用99%，求排查原因

升级Xcode到15.0并创建新项目后，在单个View内放置4-5个NavigationLink，点击跳转时App直接冻结，CPU占用率飙升至99%，必须重启App才能恢复，但重复操作问题依旧。

相关代码 #

SettingsView代码 #

struct SettingsView: View {

    var body: some View {

     VStack {
        Group {
                    
           NavigationLink {
                EditProfileView()
                    .hideNavigationBar
           } label: {
                SettingsRow(row: .editProfile)
           }
                    
           Divider()
                    
           NavigationLink {
                AccountVerificationView()
                    .hideNavigationBar
           } label: {
                SettingsRow(row: .accountVerification)
           }
                    
           Divider()
                    
           NavigationLink {
                ChangePhoneNoView()
                    .hideNavigationBar
           } label: {
                SettingsRow(row: .changeNumber)
           }
                    
           Divider()
        }
                 
     Group {
           SettingsRow(row: .notification, isToggleOn: $notificationOn)
                    
           Divider()
                    
           SettingsRow(row: .conversation, isToggleOn: $openToConversation)
                    
           Divider()
                    
           NavigationLink {
                MatchedFriends()
                   .hideNavigationBar
           } label: {
                SettingsRow(row: .matchedFriends)
         }
       }
     }
   }
}

主App代码 #

@main
struct KoyApp: App {
    
    // register app delegate for Firebase setup
    @UIApplicationDelegateAdaptor(AppDelegate.self) var delegate
    
    var body: some Scene {
        
        WindowGroup {
            NavigationStack {
                SettingsView()
                    .onOpenURL(perform: { url in
                        Auth.auth().canHandle(url)
                    })
            }
        }
    }
}

HideNavBar修饰符代码 #

struct HideNavBar : ViewModifier {
    
    func body(content: Content) -> some View {
        content
            .navigationBarTitle("")
            .navigationBarHidden(true)
            .navigationBarBackButtonHidden(true)
    }
}

extension View {
 
   var hideNavigationBar: some View {
        modifier(HideNavBar())
    }
}

问题排查与解决方案 #

1. 核心代码问题：未声明绑定状态变量 #

你的SettingsView中，SettingsRow(row: .notification, isToggleOn: $notificationOn)和SettingsRow(row: .conversation, isToggleOn: $openToConversation)使用了两个绑定变量$notificationOn、$openToConversation，但未在View内部声明对应的@State变量。这会导致SwiftUI在视图渲染时陷入无限循环，直接拉满CPU，引发App冻结。

修复方法：在SettingsView顶部添加这两个状态变量：

struct SettingsView: View {
    // 新增缺失的状态绑定变量
    @State private var notificationOn = false
    @State private var openToConversation = false
    
    var body: some View {
        // 原视图代码保持不变
    }
}

2. NavigationStack写法优化（可选） #

Xcode 15的NavigationStack对直接嵌套大量NavigationLink的场景偶尔会出现渲染冲突，虽然不是本次问题的根源，但可以改用navigationDestination的写法让代码更健壮：

struct SettingsView: View {
    @State private var notificationOn = false
    @State private var openToConversation = false
    @State private var selectedDestination: Destination?
    
    // 定义跳转目标枚举
    enum Destination {
        case editProfile, accountVerification, changeNumber, matchedFriends
    }
    
    var body: some View {
        VStack {
            Group {
                Button(action: { selectedDestination = .editProfile }) {
                    SettingsRow(row: .editProfile)
                }
                Divider()
                
                Button(action: { selectedDestination = .accountVerification }) {
                    SettingsRow(row: .accountVerification)
                }
                Divider()
                
                Button(action: { selectedDestination = .changeNumber }) {
                    SettingsRow(row: .changeNumber)
                }
                Divider()
            }
            
            Group {
                SettingsRow(row: .notification, isToggleOn: $notificationOn)
                Divider()
                
                SettingsRow(row: .conversation, isToggleOn: $openToConversation)
                Divider()
                
                Button(action: { selectedDestination = .matchedFriends }) {
                    SettingsRow(row: .matchedFriends)
                }
            }
        }
        // 统一处理跳转目标
        .navigationDestination(item: $selectedDestination) { destination in
            switch destination {
            case .editProfile:
                EditProfileView().hideNavigationBar
            case .accountVerification:
                AccountVerificationView().hideNavigationBar
            case .changeNumber:
                ChangePhoneNoView().hideNavigationBar
            case .matchedFriends:
                MatchedFriends().hideNavigationBar
            }
        }
    }
}

3. 修饰符冗余优化（可选） #

HideNavBar中的navigationBarTitle("")在iOS 14+已无必要，可简化为：

struct HideNavBar : ViewModifier {
    func body(content: Content) -> some View {
        content
            .navigationBarHidden(true)
            .navigationBarBackButtonHidden(true)
    }
}

总结 #

本次问题的核心是缺失绑定状态变量导致的视图无限渲染循环，并非Xcode 15的bug。补充@State变量后即可解决冻结问题。Xcode 15的NavigationStack虽有小兼容性细节，但不是本次故障的原因。

内容的提问来源于stack exchange，提问作者Taimoor Arif