在Tab Bar控制器之前显示登录屏幕 [英] Show a login screen before a Tab Bar Controller

问题描述

我正在做一个Twitter应用程序，并在AppDelegate -didFinishLaunchingWithOptions 我使用下一个代码来加载登录视图，如果该对象的NSUserDefaults是空的： / p>

NSUserDefaults * prefs = [NSUserDefaults standardUserDefaults];

  NSString * test = [prefs objectForKey：@username]; 
 if（test == @（null）|| test == nil）{
 LoginScreenViewController * login = [[LoginScreenViewController alloc] initWithNibName：@LoginScreenViewControllerbundle：nil]; 
 [self.window addSubview：login.view]; 
 [self.window makeKeyAndVisible]; 
 
} else {
 [self.window addSubview：tabBarController.view]; 
 [self.window makeKeyAndVisible]; 
} 
  

我可以加载登录视图，解散？登录屏幕必须在加载tabBarController之前显示，因此当Login控制器完成后，选项卡栏控制器将启动，就像之前没有任何其他视图一样。提前感谢！

解决方案

我不知道这是否会解决你的问题，但不要使用== for string比较。使用 NSString 类的 compare：方法。

  if（[myNSStringObject compare：anotherNSStringObject] == NSOrderedSame）{
 //继续根据结果匹配的字符串进行处理
} 
 else {
 //继续根据结果不匹配的字符串进行处理
} 
  

不确定如果这将产生影响，但是当你的程序变得更复杂，你可能会遇到麻烦，不这样做。

I'm doing an Twitter app, and on the AppDelegate -didFinishLaunchingWithOptions I'm using next code for loading the login view if NSUserDefaults on that object are empty:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

NSString *test = [prefs objectForKey:@"username"];
if (test == @"(null)" || test == nil) {
    LoginScreenViewController *login = [[LoginScreenViewController alloc] initWithNibName:@"LoginScreenViewController" bundle:nil];
    [self.window addSubview:login.view];
    [self.window makeKeyAndVisible];

} else {
    [self.window addSubview:tabBarController.view];
    [self.window makeKeyAndVisible];
}

And I'm able to load the login view, but then how would I dismiss it? The login screen has to show up before the tabBarController is loaded, so when the Login controller is done, the tab bar controller gets started as if it wouldn't have any other view before. Thanks in advance!

解决方案

I'm not sure if this will solve your problem, but don't use == for string comparisons. Use the compare: method of the NSString class.

if ([myNSStringObject compare:anotherNSStringObject] == NSOrderedSame) {
   //proceed with processing based on resultant matched strings
}
else {
   //proceed with processing based on resultant non-matched strings
}

Not sure if this will make a difference, but as your program becomes more complex, you might run into trouble not doing it this way.

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