objective-c - 有条件地从 AppDelegate 故事板中的不同位置开始

Question

我有一个带有工作登录和主视图控制器的故事板，后者是登录成功时用户导航到的视图控制器。我的目标是如果身份验证（存储在钥匙串中）成功则立即显示主视图控制器，如果身份验证失败则显示登录视图控制器。基本上，我想在我的 AppDelegate 中执行此操作：

// url request & response work fine, assume success is a BOOL here
// that indicates whether login was successful or not

if (success) {
          // 'push' main view controller
} else {
          // 'push' login view controller
}

我知道 performSegueWithIdentifier 方法：但是这个方法是 UIViewController 的实例方法，所以不能从 AppDelegate 中调用。如何使用我现有的故事板做到这一点？

编辑：

Storyboard 的初始视图控制器现在是一个导航控制器，它没有连接到任何东西。我使用了 setRootViewController: 区别，因为 MainIdentifier 是一个 UITabBarController。然后这就是我的线条的样子：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{        
    BOOL isLoggedIn = ...;    // got from server response

    NSString *segueId = isLoggedIn ? @"MainIdentifier" : @"LoginIdentifier";
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Storyboard" bundle:nil];
    UIViewController *initViewController = [storyboard instantiateViewControllerWithIdentifier:segueId];

    if (isLoggedIn) {
        [self.window setRootViewController:initViewController];
    } else {
        [(UINavigationController *)self.window.rootViewController pushViewController:initViewController animated:NO];
    }

    return YES;
}

欢迎提出建议/改进！

score 170 · Accepted Answer

我对这里提出的一些解决方案感到惊讶。

在你的故事板中真的不需要虚拟导航控制器，在 viewDidAppear: 或任何其他黑客上隐藏视图和触发 segues。

如果您没有在 plist 文件中配置情节提要，则必须自己创建窗口和根视图控制器：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{        
    BOOL isLoggedIn = ...;    // from your server response

    NSString *storyboardId = isLoggedIn ? @"MainIdentifier" : @"LoginIdentifier";
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Storyboard" bundle:nil];
    UIViewController *initViewController = [storyboard instantiateViewControllerWithIdentifier:storyboardId];

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.rootViewController = initViewController;
    [self.window makeKeyAndVisible];

    return YES;
}

如果在应用程序的 plist中配置了故事板，则窗口和根视图控制器将在 application:didFinishLaunching: 被调用时设置好，并且将为您在窗口上调用 makeKeyAndVisible。

在这种情况下，它甚至更简单：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{        
    BOOL isLoggedIn = ...;    // from your server response

    NSString *storyboardId = isLoggedIn ? @"MainIdentifier" : @"LoginIdentifier";
    self.window.rootViewController = [self.window.rootViewController.storyboard instantiateViewControllerWithIdentifier:storyboardId];

    return YES;
}

score 25 · Accepted Answer

我假设您的故事板设置为“主故事板”（UIMainStoryboardFile您的 Info.plist 中的键）。在这种情况下，UIKit 将加载故事板并将其初始视图控制器设置为窗口的根视图控制器，然后再发送application:didFinishLaunchingWithOptions:到 AppDelegate。

我还假设情节提要中的初始视图控制器是导航控制器，您希望将主视图控制器或登录视图控制器推送到该控制器上。

您可以向您的窗口询问其根视图控制器，并将performSegueWithIdentifier:sender:消息发送给它：

NSString *segueId = success ? @"pushMain" : @"pushLogin";
[self.window.rootViewController performSegueWithIdentifier:segueId sender:self];

score 18 · Accepted Answer

如果您的故事板的入口点不是UINavigationController：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {


    //Your View Controller Identifiers defined in Interface Builder
    NSString *firstViewControllerIdentifier  = @"LoginViewController";
    NSString *secondViewControllerIdentifier = @"MainMenuViewController";

    //check if the key exists and its value
    BOOL appHasLaunchedOnce = [[NSUserDefaults standardUserDefaults] boolForKey:@"appHasLaunchedOnce"];

    //if the key doesn't exist or its value is NO
    if (!appHasLaunchedOnce) {
        //set its value to YES
        [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"appHasLaunchedOnce"];
        [[NSUserDefaults standardUserDefaults] synchronize];
    }

    //check which view controller identifier should be used
    NSString *viewControllerIdentifier = appHasLaunchedOnce ? secondViewControllerIdentifier : firstViewControllerIdentifier;

    //IF THE STORYBOARD EXISTS IN YOUR INFO.PLIST FILE AND YOU USE A SINGLE STORYBOARD
    UIStoryboard *storyboard = self.window.rootViewController.storyboard;

    //IF THE STORYBOARD DOESN'T EXIST IN YOUR INFO.PLIST FILE OR IF YOU USE MULTIPLE STORYBOARDS
    //UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"YOUR_STORYBOARD_FILE_NAME" bundle:nil];

    //instantiate the view controller
    UIViewController *presentedViewController = [storyboard instantiateViewControllerWithIdentifier:viewControllerIdentifier];

    //IF YOU DON'T USE A NAVIGATION CONTROLLER:
    [self.window setRootViewController:presentedViewController];

    return YES;
}

如果您的故事板的入口点是UINavigationController替换：

//IF YOU DON'T USE A NAVIGATION CONTROLLER:
[self.window setRootViewController:presentedViewController];

和：

//IF YOU USE A NAVIGATION CONTROLLER AS THE ENTRY POINT IN YOUR STORYBOARD:
UINavigationController *navController = (UINavigationController *)self.window.rootViewController;
[navController pushViewController:presentedViewController animated:NO];

score 10 · Accepted Answer

在您的 AppDelegate 的application:didFinishLaunchingWithOptions方法中，在该return YES行之前，添加：

UINavigationController *navigationController = (UINavigationController*) self.window.rootViewController;
YourStartingViewController *yourStartingViewController = [[navigationController viewControllers] objectAtIndex:0];
[yourStartingViewController performSegueWithIdentifier:@"YourSegueIdentifier" sender:self];

替换YourStartingViewController为您的实际第一个视图控制器类的名称（您不想出现的那个）以及YourSegueIdentifier该起始控制器和您要实际开始的控制器之间的实际名称（segue 之后的那个））。

if如果您不总是希望它发生，则将该代码包装在条件中。

score 6 · Accepted Answer

鉴于您已经在使用 Storyboard，您可以使用它向用户展示 MyViewController，这是一个自定义控制器（稍微简化一下followben 的答案）。

在AppDelegate.m中：

-(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    MyCustomViewController *controller = [self.window.rootViewController.storyboard instantiateViewControllerWithIdentifier:@"MyCustomViewController"];

    // now configure the controller with a model, etc.

    self.window.rootViewController = controller;

    return YES;
}

传递给 instantiateViewControllerWithIdentifier 的字符串是指 Storyboard ID，可以在界面生成器中设置：

在此处输入图像描述

只需根据需要将其包装在逻辑中即可。

但是，如果您从 UINavigationController 开始，则此方法不会为您提供导航控件。

要从通过界面生成器设置的导航控制器的起点“向前跳跃”，请使用以下方法：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    UINavigationController *navigation = (UINavigationController *) self.window.rootViewController;

    [navigation.visibleViewController performSegueWithIdentifier:@"my-named-segue" sender:nil];

    return YES;
}

score 4 · Accepted Answer

为什么不先出现登录屏幕，检查用户是否已经登录并立即推送下一个屏幕？全部在 ViewDidLoad 中。

score 3 · Accepted Answer

快速实现相同：

如果您UINavigationController在情节提要中用作入口点

let storyboard = UIStoryboard(name: "Main", bundle: nil)

var rootViewController = self.window!.rootViewController as! UINavigationController;

    if(loginCondition == true){

         let profileController = storyboard.instantiateViewControllerWithIdentifier("ProfileController") as? ProfileController  
         rootViewController.pushViewController(profileController!, animated: true) 
    }
    else {

         let loginController =   storyboard.instantiateViewControllerWithIdentifier("LoginController") as? LoginController 
         rootViewController.pushViewController(loginController!, animated: true) 
    }

score 1 · Accepted Answer

这是适用于 iOS7 的解决方案。为了加快初始加载并且不进行任何不必要的加载，我的 Storyboard 文件中有一个名为“DUMMY”的完全空的 UIViewcontroller。然后我可以使用以下代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    UIStoryboard* storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];

    NSString* controllerId = @"Publications";
    if (![NSUserDefaults.standardUserDefaults boolForKey:@"hasSeenIntroduction"])
    {
        controllerId = @"Introduction";
    }
    else if (![NSUserDefaults.standardUserDefaults boolForKey:@"hasDonePersonalizationOrLogin"])
    {
        controllerId = @"PersonalizeIntro";
    }

    if ([AppDelegate isLuc])
    {
        controllerId = @"LoginStart";
    }

    if ([AppDelegate isBart] || [AppDelegate isBartiPhone4])
    {
        controllerId = @"Publications";
    }

    UIViewController* controller = [storyboard instantiateViewControllerWithIdentifier:controllerId];
    self.window.rootViewController = controller;

    return YES;
}

score 0 · Accepted Answer

我建议创建一个新的 MainViewController，它是 Navigation Controller 的 Root View Controller。为此，只需按住控件，然后拖动 Navigation Controller 和 MainViewController 之间的连接，从提示中选择“Relationship - Root View Controller”。

在 MainViewController 中：

- (void)viewDidLoad
{
    [super viewDidLoad];
    if (isLoggedIn) {
        [self performSegueWithIdentifier:@"HomeSegue" sender:nil];
    } else {
        [self performSegueWithIdentifier:@"LoginSegue" sender:nil];
    }
}

请记住在 MainViewController 与 Home 和 Login 视图控制器之间创建 segues。希望这可以帮助。:)

score 0 · Accepted Answer

在尝试了许多不同的方法之后，我能够用这个来解决这个问题：

-(void)viewWillAppear:(BOOL)animated {

    // Check if user is already logged in
    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
    if ([[prefs objectForKey:@"log"] intValue] == 1) {
        self.view.hidden = YES;
    }
}

-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];

    // Check if user is already logged in
    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
    if ([[prefs objectForKey:@"log"] intValue] == 1) {
        [self performSegueWithIdentifier:@"homeSeg3" sender:self];
    }
}

-(void)viewDidUnload {
    self.view.hidden = NO;
}

objective-c - 有条件地从 AppDelegate 故事板中的不同位置开始

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