Changing background image with button - swift

Question

I am trying to make an application function so that when the user presses one of the images(which are buttons) the background will change. My issue is that when the button is pressed the background will not change to the picture. I have been trying to look for answers but have found nothing. Is anyone able to help? https://i.stack.imgur.com/boEiZ.png <- The image is linked here because stack overflow won't allow me to imbed images.
#IBOutlet weak var background: NSImageView!
let grass = NSImage(named :NSImage.Name(rawValue: "wetgrass"))
override func viewDidLoad() {
super.viewDidLoad()
// Do view setup here.
background.image = grass
}
#IBAction func changeGrass(_ sender: Any) {
background.image = grass
}
}

Answer 1

Here is a tested answer try this
#IBAction func btnChangeImageClick(_ sender: UIButton) {
let imageFromButton : UIImage = sender.image(for: UIControlState.normal)!
imgBG.image = imageFromButton
}
Note: i make Any to UIButton in action so we can get image from that sender object

Answer 2

How to approach solving the problem:
Find out if the assignment upon button press is the problem; isolate image-setting from the button callbacks. You did that already by assigning an image in viewDidLoad ✓
Find out if the image is broken.
The image loading could fail:
let grass = NSImage(named: NSImage.Name(rawValue: "wetgrass"))
NSImage.init?(named:) produces a NSImage? aka Optional<NSImage> -- that means, loading the image file with that name could fail. Use this initializer when you're positive that ...
either your Bundle contains an image file named "wetgrass.png" that is copies into the app (check Build Settings > Copy Bundle Resources),
or your Assets asset catalogue contains an entry with the name "wetgrass".
So grass could be nil. And if it is nil, your assignment to background.image will simply remove any previously set image (if there ever was any), resetting the NSImageView to display a boring gray background.
To finally isolate and check if image assignment works, use an image that's guaranteed to exist, like the built-in ones:
let testImage = NSImage(named: .advanced)!
Note I force-unwrap the optional here with confidence since NSImage.Name.advanced is guaranteed to produce an image :)
This should work then:
override func viewDidLoad() {
super.viewDidLoad()
// Show initial image:
background.image = NSImage(named: .advanced)!
}
#IBAction func changeGrass(_ sender: Any) {
// Show grass or another built-in image:
background.image = grass ?? NSImage(named: .computer)!
}
So check your grass != nil

Answer 3

Try this:
#IBAction func changeGrass(_ sender: Any) {
if let myButton = sender as? UIButton, let currentImage = myButton.imageView?.image {
background.image = currentImage
// Animated
UIView.transition(with: background,
duration: 0.75,
options: .transitionCrossDissolve,
animations: {
self.background.image = currentImage
})
}
}