How can I call a method in one view controller from another?

Question

I thought this would be simple, but I'm really struggling with it. I have a map view in a tab bar controller, and I have a viewController that when you tap a button, it is supposed to save the user's coordinates and put an annotation on the map. I thought I could just make a boolean newPost , and set it as true, and then in the viewDidLoad method for my map view, say,

if newPost {
    var newAnnotation = MKPointAnnotation()
    var newPostCoordinate = CLLocationCoordinate2DMake(userPosts.last!.postLatitude, userPosts.last!.postLongitude)
    newAnnotation.coordinate = newPostCoordinate
    newAnnotation.title = userPosts.last!.postTitle
    mainMapView.addAnnotation(newAnnotati
    newPost = false
}

Unfortunately, the mapView doesn't reload when I go back to it after going to the new post viewController, so the viewDidLoad method doesn't get called again.

So instead, I created a new method, and tried to call it when the post button on the new post viewController is tapped. This is where I got stuck. I thought it would just be:

mapViewController.theMethodIWantToRun()

but I end up with a "missing argument for parameter #1 in call" error. My method doesn't have any arguments or return anything, so I don't think I should need arguments...

I feel like this is a pretty dumb question, but if I could figure it out, I wouldn't be here.

If you think there's a better way to do what I'm trying to do, feel free to let me know! Thanks!

Answer 1

The easiest way to do that is to move your newPost condition in viewWillAppear method. Otherwise the best approach to send data between controllers is by using delegation pattern