SwiftUI接入Firebase开发登录页报Cannot find 'ContentView' in scope错误

你遇到的报错本质是ContentView.swift文件存在多处语法错误、括号不匹配，导致整个文件编译失败，Xcode无法识别到其中定义的ContentView结构体，并非你没有定义该结构体。

具体需要修改的问题点： #

• 1. RecipyApp.swift中初始化AppViewModel实例时缺少括号：
     原代码：let viewModel = AppViewModel
     修改为：let viewModel = AppViewModel()
     前者是取类型本身，后者才是创建类实例，你之前的写法不符合Swift语法要求。
• 2. ContentView.swift中AppViewModel类的signIn、signUp方法多处缺少闭合大括号，整个类的语法结构不完整。
• 3. ContentView.swift中NavigationView缺少闭合大括号，结构体结构不完整。
• 4. SignUpView中调用singUp方法时多了不必要的$符号：
     原代码：$viewModel.singUp(email: email, password: password)
     修改为：viewModel.singUp(email: email, password: password)
$只用于生成Binding类型绑定，调用普通方法不需要加。
• 5. 整个ContentView.swift文件存在多处多余的闭合大括号、方法括号未对齐的问题，语法结构完全混乱，导致编译器无法正常解析文件内容。

修正后的核心代码片段参考： #

修正后的RecipyApp.swift #

import SwiftUI
import Firebase

@main
struct RecipyApp: App{
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
    var body: some Scene{
        let viewModel = AppViewModel()
        WindowGroup{
            ContentView()
                .environmentObject(viewModel)
        }
    }
}

class AppDelegate: NSObject, UIApplicationDelegate{
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        FirebaseApp.configure()
        return true
    }
}

修正后的ContentView.swift核心部分 #

import SwiftUI
import FirebaseAuth

class AppViewModel: ObservableObject{
    let auth = Auth.auth()
    @Published var signedIn = false
    var isSignedIn: Bool {
        return auth.currentUser != nil
    }
    
    func singIn(email: String, password: String){
        auth.signIn(withEmail: email, password: password) { [weak self] result, error in
            guard result != nil, error == nil else{
                return
            }
            DispatchQueue.main.async {
                self?.signedIn = true
            }
        }
    }
    
    func singUp(email: String, password: String){
        auth.createUser(withEmail: email, password: password) { [weak self] result, error in
            guard result != nil, error == nil else{
                return
            }
            DispatchQueue.main.async {
                self?.signedIn = true
            }
        }
    }
}

struct ContentView: View {
    @EnvironmentObject var viewModel: AppViewModel
    var body: some View {
        NavigationView{
            if viewModel.signedIn{
                Text("Signed In")
            }
            else{
                SignInView()
            }
        }
        .onAppear {
            viewModel.signedIn = viewModel.isSignedIn
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

struct SignInView: View {
    @State var email = ""
    @State var password = ""
    @EnvironmentObject var viewModel: AppViewModel
    var body: some View {
        VStack{
            TextField("Email Address", text: $email)
                .padding()
                .background(Color(.secondarySystemBackground))
            SecureField("Password", text: $password)
                .padding()
                .background(Color(.secondarySystemBackground))
            Button(action: {
                guard !email.isEmpty, !password.isEmpty else{
                    return
                }
                viewModel.singIn(email: email, password: password)
            }, label: {
                Text("Sign In")
                    .frame(width: 200, height: 50)
                    .background(Color.blue)
                    .foregroundColor(.white)
                    .cornerRadius(8)
            })
            Spacer()
        }
        .padding()
    }
}

struct SignUpView: View {
    @State var email = ""
    @State var password = ""
    @EnvironmentObject var viewModel: AppViewModel
    var body: some View {
        VStack{
            TextField("Email Address", text: $email)
                .padding()
                .background(Color(.secondarySystemBackground))
            SecureField("Password", text: $password)
                .padding()
                .background(Color(.secondarySystemBackground))
            Button(action: {
                guard !email.isEmpty, !password.isEmpty else{
                    return
                }
                viewModel.singUp(email: email, password: password)
            }, label: {
                Text("Create Account")
                    .frame(width: 200, height: 50)
                    .background(Color.blue)
                    .foregroundColor(.white)
                    .cornerRadius(8)
            })
            Spacer()
        }
        .padding()
    }
}

所有语法错误修正后重新编译即可正常识别ContentView。

内容的提问来源于stack exchange，提问作者Some User 444