Using presentViewController from UIView

Question

I am creating a title bar for my iOS application and I am making this inside a UIView. The only issue I am having is with the "home button". When the home button is pressed, it needs to go to the home page, which is ViewController.

However, it doesn't look as if [self presentViewController:vc animated:NO completion:NULL]; works for UIView.

How do I work around this problem ?

- (void) createTitlebar {

    CGRect titleBarFrame = CGRectMake(0, 0, 320, 55);

    //Create the home button on the top right of the page. When clicked, it will navigate to the home page of the application
    homeButton = [UIButton buttonWithType:UIButtonTypeCustom];
    homeButton.frame = CGRectMake(275, 10, 40, 40);
    [homeButton setTag:1];
    [homeButton setImage:[UIImage imageNamed:@"homeIcon.png"] forState:UIControlStateNormal];
    [homeButton addTarget:self action:@selector(homeButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
    [self addSubview:homeButton];
}

- (IBAction)homeButtonPressed:(id)sender{

    //Transition to the submit button page
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
    ViewController *vc = [storyboard instantiateViewControllerWithIdentifier:@"ViewController"];
    [vc setModalPresentationStyle:UIModalPresentationFullScreen];
    [self presentViewController:vc animated:NO completion:NULL];
}

Answer 1

Only UIViewController can present another view controller, so if you need to show a viewcontroller from view there are several way, one of them is like this:

make a viewcontroller on which your parent view is situated a delegate of it

ParentView *view = [ParentView new];
...
view.delegate = self;

then, inside ParentView call method of that delegate

- (IBAction)homeButtonPressed:(id)sender {
    [self.delegate buttonPressed];
}

and then, inside your VC implement

 -(void)buttonPressed {
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
    ViewController *vc = [storyboard instantiateViewControllerWithIdentifier:@"ViewController"];
    [vc setModalPresentationStyle:UIModalPresentationFullScreen];
    [self presentViewController:vc animated:NO completion:NULL];
}

If you need to keep this code inside UIView and avoid delegation you can do a trick like this (personally i don't like it but it should work)

-(void)buttonPressed{
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
    ViewController *vc = [storyboard      instantiateViewControllerWithIdentifier:@"ViewController"];
    [vc setModalPresentationStyle:UIModalPresentationFullScreen];
    [(UIViewController*)self.nextResonder presentViewController:vc animated:NO completion:NULL];
}

Answer 2

You can do this without using the delegate pattern. Here you go

ObjectiveC

UIViewController *currentTopVC = [self currentTopViewController];
currentTopVC.presentViewController......... 

- (UIViewController *)currentTopViewController {
    UIViewController *topVC = [[[[UIApplication sharedApplication] delegate] window] rootViewController];
    while (topVC.presentedViewController) {
        topVC = topVC.presentedViewController;
    }
    return topVC;
}

Swift

var topVC = UIApplication.sharedApplication().keyWindow?.rootViewController
while((topVC!.presentedViewController) != nil) {
     topVC = topVC!.presentedViewController
}
topVC?.presentViewController........

Answer 3

Here's a more idiomatic Swift 3 version of Shamsudheen's answer:

extension UIApplication {

    static func topViewController() -> UIViewController? {
        guard var top = shared.keyWindow?.rootViewController else {
            return nil
        }
        while let next = top.presentedViewController {
            top = next
        }
        return top
    } 
}

Then you can just call:

UIApplication.topViewController()?.present(...)

Answer 4

With Swift 4 - 4.2 Adding onto Shamsudheen TK's answer.

var topVC = UIApplication.shared.keyWindow?.rootViewController
    while((topVC!.presentedViewController) != nil) {
        topVC = topVC!.presentedViewController
    }
    let customViewController = CustomViewController()
    topVC?.present(customViewController, animated: true, completion: nil)

With UINavigationController: Here is also an additional feature -> You can pass along a UINavigationController with your customViewController.

 var topVC = UIApplication.shared.keyWindow?.rootViewController
    while((topVC!.presentedViewController) != nil) {
        topVC = topVC!.presentedViewController
    }
    let customViewController = CustomViewController()
    let navController = UINavigationController(rootViewController: CustomViewController)
    topVC?.present(navController, animated: true, completion: nil)

Answer 5

You can try below code

 UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
 ViewController *vc = [storyboard instantiateViewControllerWithIdentifier:@"ViewController"];
 UIViewController *vc1 = [UIApplication sharedApplication].keyWindow.rootViewController;
 [vc1 presentViewController:vc animated:YES completion:nil]; 

Answer 6

With Swift 5 (ios 13+)

guard let topVC = UIApplication.shared.windows.filter({$0.isKeyWindow}).first?.rootViewController else { return }
    let customViewController = CustomViewController()
    topVC.present(customViewController, animated: true, completion: nil)