Cannot update UIButton.image after view loads

Question

I am attempting something relatively simple. I have a UIButton that loads with an image:

@IBOutlet var peer5Outlet: UIButton!

    override func viewDidLoad() {
    super.viewDidLoad()

    peer5Outlet.enabled = true
    var img = UIImage(named: "camera")
    peer5Outlet.setImage(UIImage(named: "camera"),forState: UIControlState.Normal) }

Once it is loaded, I simply want to update that image by calling a method:

func updateButtonImage() {

    peer5Outlet.imageView!.image = UIImage(named: "connected")!

    print("peer5Outlet.imageView!.image = \(peer5Outlet!.imageView!.image!)")

}

However, I am still unable to update the image; the original image never changes in the view.

Perhaps I am missing some sort of view reload method?

You need to set the image the same way as in `viewDidLoad`, via `setImage()` — Cristik, Jan 04 '16 at 18:20

score 3 · Answer 1 · answered Jan 04 '16 at 18:23

3

Update your updateButtonImage function to

func updateButtonImage() {
    peer5Outlet.setImage(UIImage(named: "connected"), forState: .Normal)
    print("peer5Outlet.imageView!.image = \(peer5Outlet!.imageView!.image!)")
}

answered Jan 04 '16 at 18:23

Rashwan L

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Thank you - that worked. But let me trouble you for one more question - and forgive me if this is more appropriate for a separate post: My hope is to change the UIButton image from different class (Swift file). I do this by calling the method this way (SendSoundsViewControlller() is the VC with the method): SendSoundsViewController().updateButtonImage() But when I do this, the compiler tells me my UIButton is nil: fatal error: unexpectedly found nil while unwrapping an Optional value – Charlie Stephenson Jan 04 '16 at 23:41
That´s why it´s a different instance of the viewController. I can really recommend a new question or make a search there is a lot of posts at SO for this issue. – Rashwan L Jan 04 '16 at 23:42
@CharlieStephenson here is a way you could do that http://stackoverflow.com/a/25204814/5576310 – Rashwan L Jan 04 '16 at 23:58
Ah, thank you. I will give this a try. Really appreciate it. – Charlie Stephenson Jan 06 '16 at 01:53
Np, did the above solution work for you @CharlieStephenson? – Rashwan L Jan 06 '16 at 02:02

Sotiris Kaniras · Answer 2 · 2016-09-28T11:22:23.757

3

Try

peer5Outlet.setBackgroundImage(UIImage(named: "connected"), forState: UIControlState.Normal)

Edit: In order to use the setImage method, you need to change the button's type to "Custom"...

edited Sep 28 '16 at 11:22

answered Jan 04 '16 at 19:31

Sotiris Kaniras

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score 0 · Answer 3 · edited May 23 '17 at 12:19

0

You need to use the main thread whenever you're touching UIImage on UI

GCD - main vs background thread for updating a UIImageView

func updateButtonImage() {
    dispatch_async(dispatch_get_main_queue()) {
        // update image
    }
}

edited May 23 '17 at 12:19

Community

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1

answered Jan 04 '16 at 18:47

Tikhonov Aleksandr

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Cannot update UIButton.image after view loads

3 Answers3