Change View Controller Image from another View Controller Swift 2.0

Question

Can you please tell me how to change UIImageView's Image in ViewController A from View Controller B?

My Xcode version is Xcode 7, with Swift 2.0,

Thank you.

Answer 1

As thefredelement you can use NSNotification for that like in your ViewController B just add this code when you are dismissing view to ViewController A:

@IBAction func goBack(sender: AnyObject) {

    NSNotificationCenter.defaultCenter().postNotificationName("refresh", object: nil)
    self.dismissViewControllerAnimated(true, completion: nil)
}

And in your viewController A add this code in your viewDidLoad method:

override func viewDidLoad() {
    super.viewDidLoad()
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "refreshList:", name:"refresh", object: nil)
}

And add this helper method in same class:

func refreshList(notification: NSNotification){

    println("parent method is called")
    //you can change your UIImageView's Image here.

}

Now when ever you press button from ViewController B it will call this method from ViewController A.

Note: I have tested this with Xcode 6.4 and I think it will work fine with Xcode 7 too.

Answer 2

In Swift 4

1st View Controller

@IBOutlet weak var imageView: UIImageView!  // ImageView 

func goToImageChooserClass () {

    let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
    let secondVC = storyBoard.instantiateViewController(withIdentifier: "SecondVC") as! SecondVC
    secondVC.firstVC = self // Object in 2nd Controller that is a FirstVC Object
    self.present(secondVC, animated:true, completion:nil)

}

2nd View Controller

class SecondVC {
    ...
    var firstVC:FirstVC! // Object representing the firstVC
    ...
    func goBack (){
        self.dismiss(animated: true, completion: {

        self.firstVC.imageView = {insert your image here}
        })   
    }
}

Answer 3

Here is how you work with NSUserDefaults

You write like this :

let defaults = NSUserDefaults.standardUserDefaults()

defaults.setObject(image!, forKey: "image")

and read like this :

let defaults = NSUserDefaults.standardUserDefaults()

let image = defaults.objectForKey("image") as! UIImage

and set it to the imageView