在登录过程中隐藏Segue [英] Hiding a Segue on Login process

问题描述

在找到关于缺少Segue执行的一个很好的解决方案之后，由于这个 post

我正在反对另一个问题：
按照上述职位描述的方法，我正在执行我的Auth令牌在Dashboard VC中，如果未设置，我将激活指向使用委托机制的LoginVC的段落，以便在操作完成后关闭视图。现在，问题是，在第一次运行之前，我会在LoginVC被显示之前得到了仪表板VC显示一段时间。我想显示登录屏幕立即隐藏（不知何故）Dashboard VC。换句话说，我希望用户不会注意到下面的事情。

任何想法？
这是我当前的故事板设置

，我在DashboardVC中检查我的凭据：

   - （void）viewWillAppear ：（BOOL）动画{
 //检查是否设置了令牌，如果不触发登录屏幕
 NSString * token = nil; 
 NSUserDefaults * userPref = [NSUserDefaults standardUserDefaults]; 
 token = [userPref objectForKey：@AuthToken]; 
 if（token == nil）{
 NSLog（@Token not present，Login required！）; 
 [self performSegueWithIdentifier：@sLoginsender：nil]; 
 [super viewWillAppear：NO]; 
 
} 
 // [super viewWillAppear：YES]; 
} 
 
 
 //如果Segue被Logout按钮触发，我们将擦除令牌，否则
 //简单地执行登录，因为没有令牌在
  - （void）prepareForSegue：（UIStoryboardSegue *）segue sender：（id）sender {
 
 if（[sender tag] == 5）{
 NSLog（@ 用户选择注销）; 
 //删除令牌
 NSUserDefaults * userPref = [NSUserDefaults standardUserDefaults]; 
 [userPref removeObjectForKey：@AuthToken]; 
 [userPref synchronize]; 
 NSLog（@Token removed）; 
} 
 
 if（[segue.identifier isEqualToString：@sLogin]）{
 LoginViewController * livc = segue.destinationViewController; 
 livc.delegate = self; //对于代理方法
} 
 
} 
  

ElJay，我可能需要你的帮助：）

感谢大家！

解决方案

我将把代码检查登录标记，并在 viewDidLoad 中执行segue，而不是等待视图出现，你说不想要。

  if（[[NSUserDefaults standardUserDefaults] boolForKey：@LoggedIn] == NO）{
 [self performSegueWithIdentifier ：@Push LogInsender：self]; 
} 
  

，如果您使用动画片段，那么您仍然可以看到rootviewController，所以我通过创建一个不使用动画的自定义segue来解决这个问题，所以loginController立即出现。

.h文件

  @interface UIStoryboardSegueNoAnim：UIStoryboardSegue 
 
 @end 
  

.m文件

  #importUIStoryboardSegueNoAnim.h
 
 @implementation UIStoryboardSegueNoAnim 
 
  - （void）perform {
 [self.sourceViewController presentModalViewController：self.destinationViewController animated：NO]; 
} 
 
 @end 
  

after finding a good solution about a missing Segue execution thanks to this post

I'm clashing against another problem: Following the approach described in the aforementioned post I'm performing the check for my auth token in the Dashboard VC and,if not set,I activate a segue pointing to the LoginVC exploiting the delegate mechanism in order to dismiss the view once the operation is completed. Now,the problem is that on the very first run I got the Dashboard VC show for a moment before the LoginVC gets displayed. I would like to show the Login screen immediately hiding (somehow) the Dashboard VC. In other words I want the user to not notice what's really going on underneath.

Any idea? This is my current storyboard setup

and I check for my credentials in the DashboardVC like that:

- (void)viewWillAppear:(BOOL)animated {
//check if the token is set,if not trigger the Login screen
NSString* token = nil;
NSUserDefaults* userPref = [NSUserDefaults standardUserDefaults];
token = [userPref objectForKey:@"AuthToken"];
if (token == nil) {
    NSLog(@"Token not present,Login required!");
    [self performSegueWithIdentifier:@"sLogin" sender:nil];
    [super viewWillAppear:NO];

}
//[super viewWillAppear:YES];
}


// if the Segue was triggered by the "Logout" button we erase the token otherwise 
// simply perform the login since there was no token at all
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {

if ([sender tag] == 5) {
    NSLog(@"User selected Logout");
    //remove the token
    NSUserDefaults* userPref = [NSUserDefaults standardUserDefaults];
    [userPref removeObjectForKey:@"AuthToken"];
    [userPref synchronize];
    NSLog(@"Token removed.");
}

if ([segue.identifier isEqualToString:@"sLogin"]) {
    LoginViewController *livc = segue.destinationViewController;
    livc.delegate = self; // For the delegate method
}

}

@ElJay,I might need your help again :)

Thanks everybody!

解决方案

I would put the code that check for the login token and performs the segue in viewDidLoad instead of waiting for the view to appear, which you say don't want.

if ([[NSUserDefaults standardUserDefaults] boolForKey:@"LoggedIn"] == NO) {
        [self performSegueWithIdentifier:@"Push LogIn" sender:self];
    }

and also if you are using a segue with animation then you will probably still see the rootviewController, so I solved this by creating a custom segue that uses no animation so the login viewController appears immediately.

.h file

@interface UIStoryboardSegueNoAnim : UIStoryboardSegue

@end

.m file

#import "UIStoryboardSegueNoAnim.h"

@implementation UIStoryboardSegueNoAnim

- (void)perform {
    [self.sourceViewController presentModalViewController:self.destinationViewController animated:NO];
}

@end

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