CODEWITHSUNDEEP
iosstoryboardsegue
user1107173
user1107173

Reputation: 10764

iOS: Accessing the same instance of UIViewController that called the Segue

I have two view controllers. MainViewController pushes SignUp ViewController. Once SignUp View Controller dismisses, I need access to the same instance of MainViewController to update a UIButton.title.

.h MainView

//MainViewController.h
#import <UIKit/UIKit.h>


@interface MainViewController : UITableViewController 
-(void)loggedIn;

@end

.m

@interface MainViewController ()

@end    

-(void)loggedIn
{
    NSLog (@"This is Logged in inside MainView.m");
    self.logInOutButton.title = @"Logout";
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    UIViewController *destinationViewController = segue.destinationViewController;
    Signup *signUp = [destinationViewController isKindOfClass:[SignUp class]] ? (Signup*)destinationViewController : nil;
    signUp.mainViewController = self;
    NSLog(@"Preapre For Segue %@", self);
}

.h SignUp

#import <UIKit/UIKit.h>
#import "MainViewController.h"
@interface SignUp : UIViewController 
@property (strong, nonatomic) MainViewController *mainViewController;
@end

.m

@synthesize mainViewController;

- (void) loggedIn
{
    NSLog(@" MainViewController %@", mainViewController);
    [mainViewController loggedIn];
    self.presentingViewController dismissViewControllerAnimated:YES completion:nil];
}

When I do NSLog I'm getting different values:

Preapre For Seg <STMainViewController: 0x9f7d600>
MainViewController (null)

Upvotes: 2

Views: 939

Answers (1)

Mark McCorkle
Mark McCorkle

Reputation: 9414

Create a protocol / delegate. There are numerous resources on how to achieve this. In summary, you create the protocol on the destination viewController with the method you wish to run on the source and then you subscribe to that delegate from the source viewController.

Protocol Delegate

Dont forget to set the delegate from your prepareForSegue method

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    Signup *signUp = segue.destinationViewController;
    signup.delegate = self;
    NSLog(@"Preapre For Segue %@", self);

}

Upvotes: 1

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