如何根据条件设置初始视图控制器？

Question

根据用户登录到服务器的条件或不显示不同的模板。如果用户没有登录应用服务器需要显示 LoginViewController[UIViewController] 否则显示 TabBarViewcontroller[UITabBarViewController]。

因为我是第一次使用 Storyboard。任何人都可以建议我在情节提要中处理这种情况吗？

Answer 1

我是这样做的。

首先，您创建一个名为 LoginViewController 的东西。它实现了您的登录逻辑。您的根控制器是 UITabBarController。

现在在 AppDelegate 中：

- (void) doLogin:(NSDictionary *)dict
{
        TransactionsViewController *transactions;
        BalancesViewController *balances;
        ProfileViewController *profile;
        UINavigationController *navi;
        UITabBarController *root;

        root = (UITabBarController *)self.window.rootViewController;

        navi = [root.viewControllers objectAtIndex:0];
        transactions = [navi.viewControllers objectAtIndex:0];
        transactions.delegate = self;

        navi = [root.viewControllers objectAtIndex:1];
        balances = [navi.viewControllers objectAtIndex:0];
        balances.delegate = self;

        navi = [root.viewControllers objectAtIndex:2];
        profile = [navi.viewControllers objectAtIndex:0];
        profile.delegate = self;

        [transactions loadDataFromLogin:dict];
        [balances loadDataFromLogin:dict];
        [profile loadDataFromLogin:dict];
}

- (void) showLoginView
{
        assert(loginController == nil);
        assert(activityView == nil);

        UITabBarController *tabbar = (UITabBarController *)self.window.rootViewController;
        loginController = [tabbar.storyboard instantiateViewControllerWithIdentifier:@"LoginViewController"];
        loginController.delegate = self;
        [tabbar presentModalViewController:loginController animated:YES];
}

- (void) loginWithLogin:(NSDictionary *)dict relogin:(BOOL)relogin
{
        NSString *_login = [dict valueForKey:@"email"];
        NSString *_pass = [dict valueForKey:@"pass"];
        NetworkOperation *op = [NetworkOperation operationLogin:_login pass:_pass];
        [NetworkOperation enqueueOperation:op observer:self];
        if (!relogin && !loginController)
                [self doLogin:dict];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
        session = nil;
        loginController = nil;

        return YES;
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
        NSString *login = [[NSUserDefaults standardUserDefaults] stringForKey:@"email"];
        NSString *pass = [[NSUserDefaults standardUserDefaults] stringForKey:@"pass"];
        NSString *name = [[NSUserDefaults standardUserDefaults] stringForKey:@"name"];
        if ((login == nil || login.length == 0) ||
            (pass == nil || pass.length == 0) ||
            (name == nil || name.length == 0)) {
                if (!loginController) {
                        [self.window makeKeyAndVisible];
                        [self performSelector:@selector(showLoginView) withObject:nil afterDelay:0.1];
                }
        } else {
                NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:login, @"email",
                                      pass, @"pass", name, @"name", nil];
                [self loginWithLogin:dict relogin:(session != nil)];
        }
}

因此，您的应用委托会检查您是否存储了通行证和登录信息。如果是，那么它使用它们登录并切换到您的根视图控制器。在我的情况下，它是一个选项卡，以显示带有余额、交易等的几个选项卡。

如果没有登录并通过，则在根视图控制器的顶部显示登录视图控制器。

这里@session 是您当前的会话。正如您在代码中看到的，登录正在使用排队操作。

如果您需要更多详细信息，请联系我。

Answer 2

在应用委托的application:didFinishLaunchingWithOptions: 方法中创建窗口和所需的初始视图控制器：

self.window = [[UIWindow alloc] initWithFrame:UIScreen.mainScreen.bounds];  
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
if ([self isUserLoggedIn]) {  
    // Show the dashboard
    self.window.rootViewController = [storyboard instantiateViewControllerWithIdentifier:@"TabBarViewcontroller"];
} else {
    // Login
    self.window.rootViewController = [storyboard instantiateViewControllerWithIdentifier:@"LoginViewController"];
}
[self.window makeKeyAndVisible];

Answer 3

您可以通过故事板名称选择您的 ViewController：

 UIStoryboard *yourStoryboard = [UIStoryboard storyboardWithName:@"yourstoryboard"
                                                          bundle:nil];
 YourViewController *vc = [yourStoryboard instantiateViewControllerWithIdentifier:@"yourViewControllerIdentifier"];

然后呈现vc

Answer 4

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil]; if ([self isUserLoggedIn]) {
// 显示仪表板 self.window.rootViewController = [storyboard instantiateViewControllerWithIdentifier:@"first"]; } 别的 { // 登录 self.window.rootViewController = [storyboard instantiateViewControllerWithIdentifier:@"second"]; }