뷰 컨트롤러가 뷰 계층 구조에 있지 않습니까?

Question

그래서 하나의보기 컨트롤러에서 프로그래밍 방식으로 다른보기 컨트롤러로 전환하려고하므로 사용자가 로그인해야 할 때만 초기화 할 수 있습니다. 그러나 xcode는 뷰 계층 구조에 있지 않으며로드를 거부하는 오류를 계속 발생시킵니다.

ViewController.h

#import <UIKit/UIKit.h> 

@interface ViewController : UIViewController 

@end 

ViewController.m

#import "ViewController.h" 
#import "API.h" 

@interface ViewController() 

@end 

@implementation ViewController 

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    if (![[API sharedInstance] isAuthorized]) { 
     [self performSegueWithIdentifier:@"ShowLogin" sender:nil]; 
    }// Do any additional setup after loading the view, typically from a nib. 
} 

- (void)didReceiveMemoryWarning 
{ 
    [super didReceiveMemoryWarning]; 
    // Dispose of any resources that can be recreated. 
} 

@end 

LoginScreen.h (아닌 계층 제어기)

#import <UIKit/UIKit.h> 

@interface LoginScreen : UIViewController 
{ 
    //the login form fields 
    IBOutlet UITextField *fldUsername; 
    IBOutlet UITextField *fldPassword; 
} 

//action for when either button is pressed 
-(IBAction)btnLoginRegisterTapped:(id)sender; 

@end 

LoginScreen.m (제어기 명백하게 계층 구조에서)

#import "LoginScreen.h" 
#import "UIAlertView+error.h" 
#import "API.h" 
#include <CommonCrypto/CommonDigest.h> 

#define kSalt @"(protected value)" 

@implementation LoginScreen 

-(void)viewDidLoad { 
    [super viewDidLoad]; 

} 

#pragma mark - View lifecycle 

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation 
{ 
    // Return YES for supported orientations 
    return (interfaceOrientation == UIInterfaceOrientationPortrait); 
} 

-(IBAction)btnLoginRegisterTapped:(UIButton*)sender { 
    //form fields validation 
    if (fldUsername.text.length < 4 || fldPassword.text.length < 4) { 
     [UIAlertView error:@"Enter username and password over 4 chars each."]; 
     return; 
    } 
    //salt the password 
    NSString* saltedPassword = [NSString stringWithFormat:@"%@%@", fldPassword.text, kSalt]; 
    //prepare the hashed storage 
    NSString* hashedPassword = nil; 
    unsigned char hashedPasswordData[CC_SHA1_DIGEST_LENGTH]; 
    //hash the pass 
    NSData *data = [saltedPassword dataUsingEncoding: NSUTF8StringEncoding]; 
    if (CC_SHA1([data bytes], [data length], hashedPasswordData)) { 
     hashedPassword = [[NSString alloc] initWithBytes:hashedPasswordData length:sizeof(hashedPasswordData) encoding:NSASCIIStringEncoding]; 
    } else { 
     [UIAlertView error:@"Password can't be sent"]; 
     return; 
    } 
    //check whether it's a login or register 
    NSString* command = (sender.tag==1)?@"register":@"login"; 
    NSMutableDictionary* params =[NSMutableDictionary dictionaryWithObjectsAndKeys:command, @"command", fldUsername.text, @"username", hashedPassword, @"password", nil]; 
    //make the call to the web API 
    [[API sharedInstance] commandWithParams:params onCompletion:^(NSDictionary *json) { 
     //result returned 
     NSDictionary* res = [[json objectForKey:@"result"] objectAtIndex:0]; 
     if ([json objectForKey:@"error"]==nil && [[res objectForKey:@"IdUser"] intValue]>0) { 
      [[API sharedInstance] setUser: res]; 
      [self.presentingViewController dismissViewControllerAnimated:YES completion:nil]; 
      //show message to the user 
      [[[UIAlertView alloc] initWithTitle:@"Logged in" message:[NSString stringWithFormat:@"Welcome %@",[res objectForKey:@"username"]] delegate:nil cancelButtonTitle:@"Close" otherButtonTitles: nil] show]; 
     } else { 
      //error 
      [UIAlertView error:[json objectForKey:@"error"]]; 
     } 
    }]; 

} 

@end 

API.h (내 웹 서비스를 호출()를 호출 내 웹 서비스)

#import "AFHTTPClient.h" 
#import "AFNetworking.h" 

typedef void (^JSONResponseBlock)(NSDictionary* json); 

@interface API : AFHTTPClient 

@property (strong, nonatomic) NSDictionary* user; 

+(API*)sharedInstance; 
//check whether there's an authorized user 
-(BOOL)isAuthorized; 
//send an API command to the server 
-(void)commandWithParams:(NSMutableDictionary*)params onCompletion:(JSONResponseBlock)completionBlock; 
-(NSURL*)urlForImageWithId:(NSNumber*)IdPhoto isThumb:(BOOL)isThumb; 

@end 

API.m는

#import "API.h" 

//the web location of the service 
#define kAPIHost @"(protected web address)" 
#define kAPIPath @"" 

@implementation API 

@synthesize user; 

#pragma mark - Singleton methods 
/** 
* Singleton methods 
*/ 
+(API*)sharedInstance { 
    static API *sharedInstance = nil; 
    static dispatch_once_t oncePredicate; 
    dispatch_once(&oncePredicate, ^{ 
     sharedInstance = [[self alloc] initWithBaseURL:[NSURL URLWithString:kAPIHost]]; 
    }); 

    return sharedInstance; 
} 

#pragma mark - init 
//intialize the API class with the deistination host name 

-(API*)init { 
    //call super init 
    self = [super init]; 
    if (self != nil) { 
     //initialize the object 
     user = nil; 
     [self registerHTTPOperationClass:[AFJSONRequestOperation class]]; 
     // Accept HTTP Header; see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1 
     [self setDefaultHeader:@"Accept" value:@"application/json"]; 
    } 
    return self; 
} 

-(BOOL)isAuthorized { 
    return [[user objectForKey:@"IdUser"] intValue]>0; 
} 

-(void)commandWithParams:(NSMutableDictionary*)params onCompletion:(JSONResponseBlock)completionBlock { 
    NSData* uploadFile = nil; 
    if ([params objectForKey:@"file"]) { 
     uploadFile = (NSData*)[params objectForKey:@"file"]; 
     [params removeObjectForKey:@"file"]; 
    } 

    NSMutableURLRequest *apiRequest = [self multipartFormRequestWithMethod:@"POST" path:kAPIPath parameters:params constructingBodyWithBlock: ^(id <AFMultipartFormData>formData) { 
     if (uploadFile) { 
      [formData appendPartWithFileData:uploadFile name:@"file" fileName:@"photo.jpg" mimeType:@"image/jpeg"]; 
     } 
    }]; 
    AFJSONRequestOperation* operation = [[AFJSONRequestOperation alloc] initWithRequest: apiRequest]; 
    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) { 
     //success! 
     completionBlock(responseObject); 
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) { 
     //failure :(
     completionBlock([NSDictionary dictionaryWithObject:[error localizedDescription] forKey:@"error"]); 
    }]; 
    [operation start]; 
} 

-(NSURL*)urlForImageWithId:(NSNumber*)IdPhoto isThumb:(BOOL)isThumb { 
    NSString* urlString = [NSString stringWithFormat:@"%@/%@upload/%@%@.jpg", kAPIHost, kAPIPath, IdPhoto, (isThumb)?@"-thumb":@""]; 
    return [NSURL URLWithString:urlString]; 
} 

@end 

Answer 1

문제는 초기 뷰 컨트롤러의 뷰가되지 않은 것입니다 viewDidLoad가 호출 될 때까지 창에 추가되었습니다. viewDidAppear:

-(void)viewDidAppear:(BOOL)animated 
{ 
    [super viewDidAppear:animated]; 
    if (![[API sharedInstance] isAuthorized]) { 
     [self performSegueWithIdentifier:@"ShowLogin" sender:self]; 
    } 
}