在多个ViewControllers上登录UIAlertView

Question

我正在尝试为我正在为类项目开发的应用程序在系统中创建日志。此登录按钮将显示在大多数视图的导航栏上，因此我正在考虑在各种视图控制器中初始化一个单独的类以创建UIAlertView并处理应用程序与服务器的通信。我遇到的问题是在检查并保存用户名和密码后将登录文本更改为注销。我已经能够显示UIAlertView并与服务器交谈，但我一直在改变文本。我最初在视图控制器中放置了一个方法来更改文本，但没有成功，但在用户文件中更好。这是我第一次使用单身人士，所以我不确定是否正确。我是否以错误的方式去做，有没有更好的方法？谢谢你的帮助。

HomeViewController.m

- (void)viewDidAppear:(BOOL)animated { 
    [super viewDidAppear:animated]; 
    [self.navigationController setNavigationBarHidden:NO animated:YES]; 
    self.navigationController.navigationBar.topItem.title = @"Home"; 
    UIBarButtonItem *login = [[UIBarButtonItem alloc] initWithTitle:@"Log In" style:UIBarButtonItemStylePlain target:self action:@selector(log)]; 
    self.navigationController.navigationBar.topItem.rightBarButtonItem = login; 
} 
-(void)log { 
    User* singleton = [User getInstance]; 
    [singleton sign]; 
} 

/* 
-(void)logfinish { 
    if ([[NSUserDefaults standardUserDefaults] stringForKey:@"Username"] && [[NSUserDefaults standardUserDefaults] stringForKey:@"Password"]) { 
     UIBarButtonItem *logout = [[UIBarButtonItem alloc] initWithTitle:@"Log Out" style:UIBarButtonItemStylePlain target:self action:nil]; 
     self.navigationController.navigationBar.topItem.rightBarButtonItem = logout; 
    } 
}*/ 

User.m

@implementation User 

static User *singletonInstance; 

+ (User*)getInstance{ 
    if (singletonInstance == nil) { 
     singletonInstance = [[super alloc] init]; 
    } 
    return singletonInstance; 
} 

-(void)sign { 
    if (![[NSUserDefaults standardUserDefaults] stringForKey:@"Username"] && ![[NSUserDefaults standardUserDefaults] stringForKey:@"Password"]) { 
     signAlert = [[UIAlertView alloc] initWithTitle:@"Log In" message:@"Please sign into your account" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Log In", nil]; 
     signAlert.alertViewStyle = UIAlertViewStyleLoginAndPasswordInput; 
     [signAlert show]; 
    } 
} 

-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex { 
    NSString *person = [signAlert textFieldAtIndex:0].text; 
    NSString *pass = [signAlert textFieldAtIndex:1].text; 
    NSDictionary *params = @ {@"User": person, @"Password" :pass}; 

    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager]; 
    manager.responseSerializer = [AFHTTPResponseSerializer serializer]; 
    [manager GET:signIn parameters:params success:^(AFHTTPRequestOperation *operation, NSData* response) { 
     NSString *responsef = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding]; 
     //NSLog(@"%@", responsef); 
     [self check:responsef user:params]; 
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) { 
     NSLog(@"Error: %@", error); 
    }]; 
} 

-(void)check:(NSString*) pass user:(NSDictionary*)nandp { 
    if ([pass isEqualToString:@"Success"]) { 
     [[NSUserDefaults standardUserDefaults] setValue:[nandp objectForKey:@"User"] forKey:@"Username"]; 
     [[NSUserDefaults standardUserDefaults] setValue:[nandp objectForKey:@"Password"] forKey:@"Password"]; 
     //NSLog(@"%@ logged in", [[NSUserDefaults standardUserDefaults] stringForKey:@"Username"]); 
     //HomeViewController *view = [[HomeViewController alloc] init]; 
     //[view logfinish]; 
    } 
    else NSLog(@"Failure"); 
} 

Answer 1

这仅仅是一个做的方式。 声明一个实例变量，如：

@implementation User { 
UIViewController *viewController; 
} 

传递您是从作为参数调用的方法sign如的viewController：

-(void)sign:(UIViewController *)viewControllerParam { 
    if (![[NSUserDefaults standardUserDefaults] stringForKey:@"Username"] && ![[NSUserDefaults standardUserDefaults] stringForKey:@"Password"]) { 
     signAlert = [[UIAlertView alloc] initWithTitle:@"Log In" message:@"Please sign into your account" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Log In", nil]; 
     signAlert.alertViewStyle = UIAlertViewStyleLoginAndPasswordInput; 
     viewController = viewControllerParam; // assigning to ivar for future use 
     [signAlert show]; 
    } 
} 

保存这个参数去供将来参考您的实例变量。
现在你可以使用这个变量调用你的viewController的方法，它改变了右侧栏按钮项：

-(void)check:(NSString*) pass user:(NSDictionary*)nandp { 
    if ([pass isEqualToString:@"Success"]) { 
     [[NSUserDefaults standardUserDefaults] setValue:[nandp objectForKey:@"User"] forKey:@"Username"]; 
     [[NSUserDefaults standardUserDefaults] setValue:[nandp objectForKey:@"Password"] forKey:@"Password"]; 
     [viewController logfinish]; // call the respective method 
    } 
    else NSLog(@"Failure"); 
} 

希望这有助于！ :)