Pass Image from UITabBarController to subview (Swift)

Question

I am using Xcode 6 with swift .

I am trying to pass an image / UIImage from my UITabBarController to one of the subviews (tabs). The Image itself is being passed to the UITabBarController using the loadImage function (which is in return called by another UIViewController during prepareForSegue ).

//this is the tab bar controller
class DesignerTabBarController : UITabBarController{

    var pickedImage : UIImage = UIImage() //empty image

    var VC1: DesignerTabController = DesignerTabController.alloc()

        func loadImage(passedImage: UIImage){
            pickedImage = passedImage
            println(pickedImage) // image is accessible from here
        }

        override func viewDidLoad() {

        super.viewDidLoad()
            println(pickedImage) //image is accessible from here
            VC1.pickedImageView.image = pickedImage // this line gives "unexpectedly found nil when unwrapping optional"

        }


}

//this is the `UIViewcontroller` I want display the image (inside pickedImageView)
class DesignerTabController : UIViewController{

    @IBOutlet weak var pickedImageView: UIImageView!

}

I realize that my way of passing the image from the UITabBarController to the sub-view will not work, even though when there are no syntax errors displayed within Xcode (it suggested pickedImageView when I started typing so I think I am really close to the solution).

If it's not possible passing data from my UITabBarController to the (first) subview, how can I pass data directly to the first subview? As I explained above, I am passing the image from another view using prepareForSegue. Does prepareForSegue directly to the first view work in my case?

Thank you very much for any suggestions, I'll try them and get back with my findings.

Answer 1

Your tab bar controller has viewControllers property. Just iterate through it check which controller is kind of class you need.

func passImage(passedImage: UIImage)
{
  if viewControllers!.isEmpty{
    return
  }
  for index in 0...viewControllers!.count{
    if let controller = viewControllers[index] as? DesignerTabController
      controller.pickedImageView.image = passedImage
  }
}

Answer 2

solved by using viewDidLayoutSubviews() instead of viewDidLoad()

see below code for my working solution:

class DesignerTabController : UIViewController{

@IBOutlet weak var pickedImageView: UIImageView!

@IBOutlet weak var labelTest: UILabel!

override func viewDidLoad() {
    super.viewDidLoad()
}

}

class DesignerTabBarController : UITabBarController{

var pickedImage : UIImage = UIImage()

func loadImage(passedImage: UIImage){
    pickedImage = passedImage
}

override func viewDidLoad() {
    super.viewDidLoad()
}

override func viewDidLayoutSubviews() {
    if let controller = viewControllers![0] as? DesignerTabController{
        controller.pickedImageView.image = pickedImage
    }
}

}