iOS: present view controller programmatically

Question

I'm using the presentViewController:animated:completion: method to go to another view controller.

This is my code:

AddTaskViewController *add = [[AddTaskViewController alloc] init];
[self presentViewController:add animated:YES completion:nil];

This code goes to the other UIViewController but the other controller is empty. I've always been using storyboards but now I need this to be done in code.

Answer 1

If you're using a storyboard, you probably shouldn't be using alloc and init to create a new view controller. Instead, look at your storyboard and find the segue that you want to perform; it should have a unique identifier (and if not, you can set one in the right sidebar).

Once you've found the identifier for that segue, send your current view controller a -performSegueWithIdentifier:sender message:

[self performSegueWithIdentifier:@"mySegueIdentifier" sender:self];

This will cause the storyboard to instantiate an AddTaskViewController and present it in the way that you've defined for that segue.

---

If, on the other hand, you're not using a storyboard at all, then you need to give your AddTaskViewController some kind of user interface. The most common way of doing so is to initialize the controller with a nib: instead of just calling init, you'll call -initWithNibName:bundle: and provide the name of a .xib file that contains your add-task UI:

AddTaskViewController *add = [[AddTaskViewController alloc]
                              initWithNibName:@"AddTaskView" bundle:nil];
[self presentViewController:add animated:YES completion:nil];

(There are other (less common) ways of getting a view associated with your new view controller, but this will probably present you the least trouble to get working.)

Answer 2

If you are using Storyboard and your "add" viewController is in storyboard then set an identifier for your "add" viewcontroller in settings so you can do something like this:

UIStoryboard* storyboard = [UIStoryboard storyboardWithName:@"NameOfYourStoryBoard" 
                                                     bundle:nil];
AddTaskViewController *add = 
           [storyboard instantiateViewControllerWithIdentifier:@"viewControllerIdentifier"];

[self presentViewController:add 
                   animated:YES 
                 completion:nil];

if you do not have your "add" viewController in storyboard or a nib file and want to create the whole thing programmaticaly then appDocs says:

If you cannot define your views in a storyboard or a nib file, override the loadView method to manually instantiate a view hierarchy and assign it to the view property.

Answer 3

You need to set storyboard Id from storyboard identity inspector

 AddTaskViewController *add=[self.storyboard instantiateViewControllerWithIdentifier:@"storyboard_id"];
 [self presentViewController:add animated:YES completion:nil];