iOS Swift Firebase在应用程序启动时检查用户不起作用

Question

我用 firebase 开发了一个应用程序。应用程序会检查是否有用户在每次启动时登录到 sceneDelegate.swift 文件中。但它仅适用于 iOS 13 设备。 iOS 12 设备用户每次都必须登录。我该如何解决这个问题？谢谢。

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

var window: UIWindow?
@available(iOS 13.0, *)
func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
    // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
    // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).

    let currentUser = Auth.auth().currentUser

    if currentUser != nil {

        let board = UIStoryboard(name: "Main", bundle: nil)
        let navigationController = board.instantiateViewController(identifier: "navigationController") as! UINavigationController
        window?.rootViewController = navigationController

    }


    guard let _ = (scene as? UIWindowScene) else { return }
}

Answer 1

SceneDelegate 是在 iOS 13 中引入的。对于 iOS 12 及更低版本，您应该在 AppDelegate 的 didFinishLaunchingWithOptions 方法中实现相同的逻辑，如下所示：

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        window = UIWindow()
        window?.makeKeyAndVisible()
        let currentUser = Auth.auth().currentUser

        if currentUser != nil {
            let board = UIStoryboard(name: "Main", bundle: nil)
            let navigationController = board.instantiateViewController(withIdentifier: "navigationController") as! UINavigationController
            window?.rootViewController = navigationController
        }
        return true
    }
}