Parent View Controller extension

Question

I'm trying to implement a sharing method which will allow to share data between parent view controller and child view controller. In Objective-C I could do it like this:

@implementation UIViewController(MyParentViewController)

- (MyParentViewController*)containerController
{
    UIViewController *parent = self;
    Class parentClass = [MyParentViewController class];
    while ( nil != (parent = [parent parentViewController]) && ![parent isKindOfClass:parentClass] ) {}
    return (id)parent;
}

@end

This allows child view controller to create an instance of its parent view controller just by adding MyParentViewController *containerController = self.containerController; So the question is how to implement something similar in Swift 4? Thanks in advance!

Answer 1

This is a rudimentary implementation of what you want to achieve. Anyway, it's not sharing. It's a way that allow a controller to grab an instance of a specific controller, if there is any relationship of parent-child containment.

extension UIViewController {
    var containerController: MyParentViewController? {
        var parentController: UIViewController? = parent
        while parentController as? MyParentViewController == nil {
            parentController = parentController?.parent
        }
        if let controller = parentController as? MyParentViewController {
            return controller
        }
        return nil
    }
}