iOS objective c passing data between view controllers

Question

I am new to iOS and I am not able to pass data from one controller to another. I am not able to access the variable in the second view controller

this is my method for passing I have created a delegate in .h file of receiving view controller

.h file of first view controller (sending) @interface OtpViewController : UIViewController @property (nonatomic,strong) NSString *str; @property (strong,nonatomic) NSString *tmp; @property(weak,nonatomic) NSString *requestReply ;

.m file of first view controller(sending)

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(nullable id)sender{
    VerifyViewController *loadCtr = (VerifyViewController *)segue.destinationViewController;
loadCtr.delegate = self;
loadCtr.tmpStr = self.tmp;
NSLog(@"--%@",self.tmp);
[loadCtr setotp:self.tmpdict withMobile:_mobiletf.text];
//NSLog(@"otp:%@",[tmpdict valueForKey:@"otp"]);
NSLog(@"mobile:%@",_mobiletf.text);
}

.m file of second view controller(receiving)

-(void)setotp:(NSDictionary *)dic withMobile:(NSString *)str{
self.stri=[tmpdict valueforkey:@"otp"];
self.stri1=_mobiletf.text;
OtpViewController.[tmpdict valueforkey:@"otp"]=self.stri;
NSLog(@"%@----%@",self.stri,self.stri1);
}

.h file of second view controller(receiving)

@protocol VerifyViewControllerDelegate <NSObject>
@end

@interface VerifyViewController : UIViewController
@property (nonatomic,strong) NSString *otpStr;
@property(nonatomic,strong) NSString *mobileStr;

@end

actually I am trying to get otp from server and I have extracted the otp in the first view controller and now I have to pass otp and the mobile number from the text field to second view controller for verification of the otp please help!!

 NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
        [[session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
            NSString *requestReply = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding]; // this is json string
         //   NSError *error;
            NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error]; // you need to convert to dictionary object
            NSLog(@"requestReply: %@", jsonDict);
            self.tmp=[jsonDict valueForKey:@"otp"] ;
            self.str=self.tmp;
            NSLog(@"tmp storage inside block:%@",self.tmp);
    }] resume];
    [ self performSegueWithIdentifier:@"b1" sender:self];
    NSLog(@" storage:%@",self.str);
    NSLog(@"tmp storage:%@",self.tmp);
}

at log whatever is printed which is out of resume gives me null

this is my log data

2017-06-01 12:26:45.803 MenuBar[2652:124758] 9047038606
2017-06-01 12:26:45.809 MenuBar[2652:124758]  storage:(null)
2017-06-01 12:26:45.810 MenuBar[2652:124758] tmp storage:(null)
2017-06-01 12:26:48.422 MenuBar[2652:124804] requestReply: {
otp = 325106;
success = 1;
}
2017-06-01 12:26:48.422 MenuBar[2652:124804] tmp storage inside block:325106

Answer 1

Use Below code:

@interface VerifyViewController : UIViewController
@property (nonatomic,strong) NSString *otpStr;
@property(nonatomic,strong) NSString *mobileStr;

Then pass values:

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(nullable id)sender
{
    VerifyViewController *loadCtr = (VerifyViewController *)segue.destinationViewController;
     loadCtr.otpStr = [tmpdict valueForKey:@"otp"];
     loadCtr.mobileStr = _mobiletf.text;
}

You can access these 2 values in ViewDidLoad method of VerifyViewController.

self.otpStr and self. mobileStr

Answer 2

(As of Xcode Version 9.4.1 (9F2000) - iOS 11.4 - Objective C) 
Most will need to call several storyboard segue calls from a single UIViewController. Here is how to handle the different segue string identifiers within the preparForSegue delegate call.

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {

    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
    if ([segue.identifier isEqualToString:  @“CallerViewController_ToMusicPlayerViewController_Segue"])
    {
        MusicPlayerViewController * targetVC = (MusicPlayerViewController *)segue.destinationViewController;
        targetVC.listName = @“Music Hits”;
    }
    if ([segue.identifier isEqualToString: @“CallerViewController_ToMusicListViewController_Segue"])
    {
        MusicListViewController * targetVC = (MusicListViewController *)segue.destinationViewController;
        // if you need to manage a protocol delegate with caller VC 
         targetVC.savefolderChoiceDelegate = self;
    }
}

The actual call to invoke the segue looks like:

-(void)buttonAction:(id)sender{
    [self performSegueWithIdentifier:@“CallerViewController_ToMusicPlayerViewController_Segue" sender:sender];
}

Here is an example of Interface Builder Segue. the identifier is different, but imagine @“CallerViewController_ToMusicPlayerViewController_Segue" is actually @"ProtData_Add_Segue" in this image.