Question

I have a custom UIButton class in my IPhone navigation application. When the user clicks the button I present a modal view which displays a tableview list of records that the user can select from.

On click of the button I create my viewController and show it using the following code:

-(void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
    dropDownPickerViewController = [[DropDownListingViewController alloc] initWithNibName:@"DropDownListingView" bundle:[NSBundle mainBundle]];
    .....
    .....

[[(AppDelegate_iPhone *)[[UIApplication sharedApplication] delegate] navigationController] presentModalViewController:dropDownPickerViewController animated:NO];
[dropDownPickerViewController release];

[super touchesEnded:touches withEvent:event];
}

As you can see the button could be on any viewController so I grab the navigationController from the app delegate. Than in my DropDownPickerViewController code i have the following when a user selects a record:

[[(AppDelegate_iPhone *)[[UIApplication sharedApplication] delegate] navigationController] dismissModalViewControllerAnimated:NO];

But nothing occurs. It seems to freeze and hang and not allow any interaction with the form. Any ideas on why my ModalViewController wouldnt be dismissing? Im thinking it is the way I use the app delegate to present the viewController. Is there a way to go self.ParentViewController in a UIButton class so I can get the ViewController of the view that the button is in (if this is the problem)?

Any ideas would be greatly appreciated.

Thanks

Answer 1

I did recall that I did have to do something similar once, and by looking at this post:

Get to UIViewController from UIView?

I was able to create some categories:

//
//  UIKitCategories.h
//

#import <Foundation/Foundation.h>

@interface UIView (FindUIViewController)
- (UIViewController *) firstAvailableUIViewController;
- (id) traverseResponderChainForUIViewController;
@end

@interface UIView (FindUINavigationController)
- (UINavigationController *) firstAvailableUINavigationController;
- (id) traverseResponderChainForUINavigationController;
@end




//
//  UIKitCategories.m
//

#import "UIKitCategories.h"

@implementation UIView (FindUIViewController)
- (UIViewController *) firstAvailableUIViewController {
    // convenience function for casting and to "mask" the recursive function
    return (UIViewController *)[self traverseResponderChainForUIViewController];
}

- (id) traverseResponderChainForUIViewController {
    id nextResponder = [self nextResponder];
    if ([nextResponder isKindOfClass:[UIViewController class]]) {
        return nextResponder;
    } else if ([nextResponder isKindOfClass:[UIView class]]) {
        return [nextResponder traverseResponderChainForUIViewController];
    } else {
        return nil;
    }
}

@end

@implementation UIView (FindUINavigationController)
- (UINavigationController *) firstAvailableUINavigationController {
    // convenience function for casting and to "mask" the recursive function
    return (UINavigationController *)[self traverseResponderChainForUINavigationController];
}

- (id) traverseResponderChainForUINavigationController {
    id nextResponder = [self nextResponder];
    if ([nextResponder isKindOfClass:[UINavigationController class]]) {
        return nextResponder;
    } else {
        if ([nextResponder isKindOfClass:[UIViewController class]]) {
            //NSLog(@" this is a UIViewController ");
            return [nextResponder traverseResponderChainForUINavigationController];
        } else {
            if ([nextResponder isKindOfClass:[UIView class]]) {
                return [nextResponder traverseResponderChainForUINavigationController];
            } else {
                return nil;
            }
        }
    }
}

@end

you can then call them like so:

UINavigationController *myNavController = [self firstAvailableUINavigationController];

UIViewController *myViewController = [self firstAvailableUIViewController];

maybe they will help you, I hope so.