[ios] Present and dismiss modal view controller

Can anyone give me the example code that I can use to first present a modal view controller, then dismiss it? This is what I have been trying:

NSLog(@"%@", blue.modalViewController);
[blue presentModalViewController:red animated:YES];
NSLog(@"%@", blue.modalViewController);
[blue dismissModalViewControllerAnimated:YES];
NSLog(@"%@", blue.modalViewController);

This code is in viewDidLoad ("blue" and "red" are both subclasses of UIViewController). I expect that I will show the red view and then immediately hide it, with some animation. However this piece of code only presents the modal view and does not dismiss it. Any idea? The first log shows "null" while the two other logs show <RedViewController: 0x3d21bf0>

Another point is, if I put this code in applicationDidFinishLaunching: the red view does not appear at all, and all logs get "null"

Swift

self.dismissViewControllerAnimated(true, completion: nil)

Swift

Updated for Swift 3

Storyboard

Create two View Controllers with a button on each. For the second view controller, set the class name to SecondViewController and the storyboard ID to secondVC.

Code

ViewController.swift

import UIKit
class ViewController: UIViewController {

    @IBAction func presentButtonTapped(_ sender: UIButton) {
        
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let myModalViewController = storyboard.instantiateViewController(withIdentifier: "secondVC")
        myModalViewController.modalPresentationStyle = UIModalPresentationStyle.fullScreen
        myModalViewController.modalTransitionStyle = UIModalTransitionStyle.coverVertical
        self.present(myModalViewController, animated: true, completion: nil)
    }
}

SecondViewController.swift

import UIKit
class SecondViewController: UIViewController {
    
    @IBAction func dismissButtonTapped(_ sender: UIButton) {
        self.dismiss(animated: true, completion: nil)
    }
}

Source:

• Documentation
• SO answer

The easiest way to do it is using Storyboard and a Segue.

Just create a Segue from the FirstViewController (not the Navigation Controller) of your TabBarController to a LoginViewController with the login UI and name it "showLogin".

Create a method that returns a BOOL to validate if the user logged in and/or his/her session is valid... preferably on the AppDelegate. Call it isSessionValid.

On your FirstViewController.m override the method viewDidAppear as follows:

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    if([self isSessionValid]==NO){
        [self performSegueWithIdentifier:@"showLogin" sender:self];
    }
}

Then if the user logged in successfully, just dismiss or pop-out the LoginViewController to show your tabs.

Works 100%!

Hope it helps!

The easiest way i tired in xcode 4.52 was to create an additional view and connect them by using segue modal(control drag the button from view one to the second view, chose Modal). Then drag in a button to second view or the modal view that you created. Control and drag this button to the header file and use action connection. This will create an IBaction in your controller.m file. Find your button action type in the code.

[self dismissViewControllerAnimated:YES completion:nil];

presentModalViewController:

MainViewController *mainViewController=[[MainViewController alloc]init];
[self.navigationController presentModalViewController:mainViewController animated:YES];

dismissModalViewController:

[self dismissModalViewControllerAnimated:YES];