Question

I am using multiple view controllers and trying the link the UITextfield in one view controller to the label in another view controller using delegate.

ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController <UITextFieldDelegate>
{
    IBOutlet UITextField *txtField;

}

@end

ViewController.m

#import "ViewController.h"
#import "ViewController2nd.h"


@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField{

    lbl.text = [NSString stringWithFormat:@"Hello, %@",txtField.text]
    [txtField resignFirstResponder];
    return YES;
}

@end

ViewController2nd.h

#import <UIKit/UIKit.h>

@interface ViewController2nd : UIViewController <UITextFieldDelegate> {

    IBOutlet UILabel *lbl;
}

@end

ViewController2nd.m

#import "ViewController2nd.h"

@interface ViewController2nd ()

@end

@implementation ViewController2nd

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
}

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

@end

The error i get is:

Use of undeclared identifier lbl in Viewcontroller.m

Not sure how to solve this problem. Need some guidance.. Thanks…

Answer 1

You don’t have scope/excess of ViewController2nd‘s IBOutlet UILabel *lbl; in ViewController for this you need custom delegates, a ViewController a delegate of ViewController2nd and pass data back. Have a look at this post for more details.