Question

I realize this question has been asked to death, at least once a month on stackoverflow for the last couple of years, but I still cannot find a solution.

I have two ViewControllers stemming from a UITabBarController. Both are initialized through the storyboard. I am attempting to call a method of one VC from another. The instance method, of course.

I have heard of the following possibilities:

1: NSNotifications

2: Defining protocol and declaring one VC as the delegate of another.

3: Actually calling the method somehow through RootViewController.

I have the code working through NSNotifications, but I dislike the concept, and I would like to understand the correct way to do it. I am most interested in possibility (3), then (2) as a last resort.

I tried to get (2) to work for several hours, but without initializing the delegate VC from the other VC, I am stumped. (Not an option due to storyboards).

Is either (2) or (3) possible? How so?

What are my misunderstandings about preferred iOS architecture if neither are possible?

Answer 1

Yes, 3 is possible. Let’s say you have two UIViewController classes, FooViewController (tab index 0) and BarViewController (tab index 1). And let’s say you want to call FooViewController‘s -(void)doFoo method from BarViewController.

In BarViewController, do [(FooViewController *)[self.tabBarController.viewControllers objectAtIndex:0] doFoo].