ios - 如何为 Realm 设置默认的 SyncConfiguration，以便我可以在多个 ViewController 中获取它而无需冗余代码？

Question

根据:

• Proper Realm usage patterns/best practices
• What is the best practice or design pattern to maintain sync activity across multiple views
• Design Pattern for Realm Database Swift 3.1 - Singleton

我的方法是这样的:

AppDelegate.swift

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
    DispatchQueue.main.async {
        let username = "test@test.com"
        let password = "Test123"
        let serverUrl = URL(string: "http://test.com:9080")
        let realmUrl = URL(string: "realm://test.com:9080/~/realmtest")

        if let user = SyncUser.current {
            Realm.Configuration.defaultConfiguration.syncConfiguration = SyncConfiguration(user: user, realmURL: realmUrl!)
        } else {
            SyncUser.logIn(with: .usernamePassword(username: username, password: password, register: false), server: serverUrl!, onCompletion: { (user, error) in
                guard let user = user else {
                    print("Error: \(String(describing: error?.localizedDescription))")
                    return
                }
                Realm.Configuration.defaultConfiguration.syncConfiguration = SyncConfiguration(user: user, realmURL: realmUrl!)
            })
        }
    }

    return true
}

ViewController.swift

override func viewDidLoad() {
    super.viewDidLoad()
    print("SyncConfiguration: \(String(describing: Realm.Configuration.defaultConfiguration.syncConfiguration))")
    self.realm = try! Realm()
}

当我第一次打开应用程序时，没有任何反应，但当我第二次打开应用程序时，Realm 工作正常。

每当我打开应用程序时，打印的 SyncConfiguration 为 nil。没有错误!

到处搜索但找不到答案...

Answer 1

问题是您正在使用异步方法来配置您的 Realm ，但您没有在方法的完成处理程序中调用打印。您应该只在异步调用完成后才显示 View Controller 。