Best way to present a ViewController from many different ViewController - ios

Question

I have n number of different ViewController's, so I want to present a PresentViewController from any other ViewControllers in Objective-C
How I am doing Currently:
So currently i am doing like this import "PresentViewController.h" in all ViewControllers then calling following code to present it:
NSString * storyboardName = #"MainStoryboard";
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:storyboardName bundle: nil];
PresentViewController * vc = [storyboard instantiateViewControllerWithIdentifier:#"IDENTIFIER_OF_YOUR_VIEWCONTROLLER"];
[self presentViewController:vc animated:YES completion:nil];
But by this way I have to import "PresentViewController.h" file into all other ViewControllers which seems very irritating job.
What I am looking for:
Is there any other way to present PresentViewController from a particular place and it can be presented whenever it needed from any ViewControllers?

Answer 1

If that is really all the code you've got, you are not doing anything with PresentViewController unique to it, so just don't mention it by name in your code:
UIViewController * vc = [storyboard instantiateViewControllerWithIdentifier:#"IDENTIFIER_OF_YOUR_VIEWCONTROLLER"];
[self presentViewController:vc animated:YES completion:nil];
If you don't mention it in your code, you don't need to import it.
But obviously if you do something with PresentViewController, like call a method of it, then things are more complicated. You could cast to id, in which case you can call any method, provided the compiler knows about it (also known as an informal protocol). But in general it would be better just to bite the bullet and do the import.

Answer 2

The problem isn’t that you have to import that header all over the place, but rather that:
you’re repeating that code all over the place;
you’re exposing internal implementation details about PresentViewController (such as its storyboard name and storyboard identifier) to other classes; and
if you ever want to change this to include some additional parameter, you’re going to have to manually hunt through your code for where changes are necessary rather than just changing some public interface that the compiler will then be able to warn you of issues.
Personally, I’d define an extension to UIViewController:
// UIViewController+Foo.h
#interface UIViewController(Foo)
- (void)presentFoo;
- (void)presentFooWithCompletion:(void (^)(void))completion;
#end
And
// UIViewController+Foo.m
#implementation UIViewController(Foo)
- (void)presentFoo {
[self presentFooWithCompletion:nil];
}
- (void)presentFooWithCompletion:(void (^)(void))completion {
NSString *storyboardName = #"MainStoryboard";
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:storyboardName bundle: nil];
UIViewController *vc = [storyboard instantiateViewControllerWithIdentifier:#"IDENTIFIER_OF_YOUR_VIEWCONTROLLER"];
[self presentViewController:vc animated:YES completion:completion];
}
#end
Then any view controller that needs to present this scene can have
#import “UIViewController+Foo.h”
And
[self presentFoo];
Or if you don’t want it as an extension to UIViewController, you could define these as class methods (using the + instead of -) of your PresentViewController. But the idea is the same: Define some simple interface that all your view controllers can call without getting lost in the implementation details of PresentViewController.
Now, obviously, I have no idea what this view controller does, so I used Foo as a placeholder. You’d obviously replace that with whatever the functional purpose of this view controller is. E.g. if it was to present a “network error” message, then I’d call the methods and filenames with presentNetworkError, UIViewController+NetworkError.h, etc. But hopefully this illustrates the idea.