打开包装时非零用户崩溃-Firebase，SwiftUI

不允许在SwiftUI视图中以常规方式展开值，但您可以在

主体

内展开，例如

HStack

或

VStack

。下面我正在尝试打开一个用户，我确信它不是零。My

LoginView

允许用户在Firebase Firestore上创建帐户，如果用户输入了正确的值，则让您登录，如果用户输入的值不正确，则显示警报视图

在我的

HomeView.swift

（启动后的第一个屏幕）中，我试图显示用户图像时崩溃。但是，当我打开该用户时，该用户在控制台中仍然为零。我认为这是因为Firebase在视图初始化之前没有时间加载图像。但我可能错了。救命啊

struct HomeProfileView: View {
    @EnvironmentObject var session: SessionStore
    @State var showDashboard = false
    var user: User?
    
    var body: some View {
        if user != nil {
            URLImage(URL(string: user!.profileImageUrl)!, content: {
                $0.image
                    .resizable()
                    .aspectRatio(contentMode: .fill)
                    .clipShape(Circle())
            })
            .frame(width: 50, height: 50)
            .background(Color(#colorLiteral(red: 0.9490196078, green: 0.9490196078, blue: 0.9490196078, alpha: 1)))
            .clipShape(Circle())
            .shadow(color: Color.black.opacity(0.1), radius: 1, x: 0, y: 1)
            .shadow(color: Color.black.opacity(0.2), radius: 10, x: 0, y: 10)
            .sheet(isPresented: $showDashboard) {
                DashboardView(showDashboard: $showDashboard)
            }
        }
    }
}

我不认为我需要一个可选的用户，但我不知道如何安全地打开用户，否则。另一个版本使用会话

EnvironmentObject

访问当前登录的用户

struct HomeProfileView: View {
    @EnvironmentObject var session: SessionStore
    @State var showDashboard = false
    
    var body: some View {
        if session.isLoggedIn {
            URLImage(URL(string: session.userSession!.profileImageUrl)!, content: {
                $0.image
                    .resizable()
                    .aspectRatio(contentMode: .fill)
                    .clipShape(Circle())
            })
            .frame(width: 50, height: 50)
            .background(Color(#colorLiteral(red: 0.9490196078, green: 0.9490196078, blue: 0.9490196078, alpha: 1)))
            .clipShape(Circle())
            .shadow(color: Color.black.opacity(0.1), radius: 1, x: 0, y: 1)
            .shadow(color: Color.black.opacity(0.2), radius: 10, x: 0, y: 10)
            .sheet(isPresented: $showDashboard) {
                DashboardView(showDashboard: $showDashboard)
            }
        }
    }
}

会话

属性属于

会话存储

类，本质上是可选的

用户

import Foundation
import Combine
import Firebase

class SessionStore: ObservableObject {
    
    @Published var isLoggedIn: Bool = UserDefaults.standard.bool(forKey: "isLoggedIn") {
        didSet {
            UserDefaults.standard.set(self.isLoggedIn, forKey: "isLoggedIn")
        }
    }

    var userSession: User?
    
    var handle: AuthStateDidChangeListenerHandle?
    
    func listenAuthenticationState() {
        handle = Auth.auth().addStateDidChangeListener({ (auth, user) in
            if let user = user {
                print(user.email as Any)
                let firestoreUserId = Ref.FIRESTORE_DOCUMENT_USERID(userId: user.uid)
                firestoreUserId.getDocument { (document, error) in
                    if let dict = document?.data() {
                        guard let decodeUser = try? User.init(fromDictionary: dict) else { return }
                        self.userSession = decodeUser
                    }
                }
                self.isLoggedIn = true
            } else {
                print("User is Logged Out")
                self.isLoggedIn = false
                self.userSession = nil
            }
        })
    }
}

---

登录的用户确实已登录，但我无法访问任何属性。

在设置userSession的位置准确设置isLoggedIn，因为它是在异步回调中完成的，并在主队列上执行此操作（以正确更新UI）

---

我有这个工作。不确定它的可扩展性，但我正在做一个不等于零的测试。我还将它放在一个按钮中，与

ontapsignate

进行切换

struct HomeProfileView: View {
    @EnvironmentObject var session: SessionStore
    @State var showDashboard = false
    
    var body: some View {
        if session.isLoggedIn {
            if (session.userSession?.profileImageUrl) != nil {
                Button(action: { self.showDashboard.toggle() } ) {
                    URLImage(URL(string: session.userSession!.profileImageUrl)!, content: {
                        $0.image
                            .resizable()
                            .aspectRatio(contentMode: .fill)
                            .clipShape(Circle())
                    })
                    .frame(width: 50, height: 50)
                    .background(Color(#colorLiteral(red: 0.9490196078, green: 0.9490196078, blue: 0.9490196078, alpha: 1)))
                    .clipShape(Circle())
                    .shadow(color: Color.black.opacity(0.1), radius: 1, x: 0, y: 1)
                    .shadow(color: Color.black.opacity(0.2), radius: 10, x: 0, y: 10)
                    .sheet(isPresented: $showDashboard) {
                        DashboardView(showDashboard: $showDashboard)
                    }
                }
            }
        }
    }
}

---

我的

session.userSession

仍然为零，我仍在崩溃。调用

Dispatch.main.async

很好，尽管错误发生在我的profileImageUrl上，即<代码>会话.userSession.profileImageUrl

struct HomeProfileView: View {
    @EnvironmentObject var session: SessionStore
    @State var showDashboard = false
    
    var body: some View {
        if session.isLoggedIn {
            if (session.userSession?.profileImageUrl) != nil {
                Button(action: { self.showDashboard.toggle() } ) {
                    URLImage(URL(string: session.userSession!.profileImageUrl)!, content: {
                        $0.image
                            .resizable()
                            .aspectRatio(contentMode: .fill)
                            .clipShape(Circle())
                    })
                    .frame(width: 50, height: 50)
                    .background(Color(#colorLiteral(red: 0.9490196078, green: 0.9490196078, blue: 0.9490196078, alpha: 1)))
                    .clipShape(Circle())
                    .shadow(color: Color.black.opacity(0.1), radius: 1, x: 0, y: 1)
                    .shadow(color: Color.black.opacity(0.2), radius: 10, x: 0, y: 10)
                    .sheet(isPresented: $showDashboard) {
                        DashboardView(showDashboard: $showDashboard)
                    }
                }
            }
        }
    }
}