Question

When the user pressed an ‘add’ button a modal view pops up for them to enter information. I have a ‘cancel’ button in the top left of a navigation bar and I want it to dismiss the current view controller when it is pressed. How do I set an object as the class’s delegate? I understand creating protocols and implementing its methods but I cannot seem to make the delegate be set. When running the debugger my [self delegate] in the ‘add’ view controller is always nil.

Answer 1

Are you spawning the modal viewController through a segue set up in your Storyboard? If so, then in the prepareForSegue: method you would set the delegate there.

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{ 
    if([identifier isEqualToString:@"userGuideSegue_home"]){
        UserGuideViewController* vc = segue.destinationViewController;
          [[segue destinationViewController] setDelegate:self];
    }

}

On the other hand, if you are setting up the modal viewController entirely through code, then you would create an instance of the modal viewController then set it’s delegate.

- (void)showModelView:(NSString*)viewName
{
    // code ripped out of project so a bit specific

    if ([viewName isEqualToString:@"userGuide_name"]) {
        modalViewController = (UserGuideViewController * )
        [[UIStoryboard storyboardWithName:@"MainStoryboard_iPhone" bundle:NULL] 
         instantiateViewControllerWithIdentifier:@"UserGuide"];
    }

    modalViewController.delegate = self;
    modalViewController.modalPresentationStyle = UIModalPresentationFormSheet;
    modalViewController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    modalViewController.view.frame = [[UIScreen mainScreen] applicationFrame];; 


    [self presentViewController:modalViewController 
                       animated:YES 
                     completion:^{
                         //put your code here
                     }];
}

Of course all this assumes you have defined a delegate property on your modal viewController.