Change background image with button click - ios

Question

I can change background image on viewDidLoad func like this:
let myBackgroundImage = UIImageView (frame: UIScreen.main.bounds)
myBackgroundImage.image = UIImage(named: "wallpaper-1-iphone-8-plus.png")
myBackgroundImage.contentMode = UIViewContentMode.scaleAspectFill
self.view.insertSubview(myBackgroundImage, at: 0)
i would like to do same action with button click like this:
#IBAction func flip4btn5(_ sender: Any)
{
let myBackgroundImage = UIImageView (frame: UIScreen.main.bounds)
myBackgroundImage.image = UIImage(named: "wallpaper-2-iphone-8-plus.png")
myBackgroundImage.contentMode = UIViewContentMode.scaleAspectFill
self.view.insertSubview(myBackgroundImage, at: 0)
}
but it does not change background image. Why ? What do you think ?
I'm using Swift 4.1.

Answer 1

Don't create a new image. just change the picture of the first UIImage in your button action like this:
myBackgroundImage.image = UIImage(named: "wallpaper-2-iphone-8-plus.png")

Answer 2

Try this code, It's working fine.
class ViewController: UIViewController {
var myBackgroundImage = UIImageView (frame: UIScreen.main.bounds);
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
myBackgroundImage.image = UIImage(named: "wallpaper-1-iphone-8-plus.png")
myBackgroundImage.contentMode = UIViewContentMode.scaleAspectFill
self.view.insertSubview(myBackgroundImage, at: 0)
}
#IBAction func flip4btn5(_ sender: UIButton) {
myBackgroundImage.image = UIImage(named: "wallpaper-2-iphone-8-plus.png")
}
}

Answer 3

Don't keep adding UIImageViews everytime you want to change the background image.
Place a UIImageView in the view hierarchy where it is needed and keep a reference to it. Then set the image property on it as needed.
class ViewController: UIViewController {
#IBOutlet weak var backgroundImageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
backgroundImageView.image = UIImage(named: "wallpaper-1-iphone-8-plus.png")
}
#IBAction func flip4btn5(_ sender: Any) {
backgroundImageView.image = UIImage(named: "wallpaper-2-iphone-8-plus.png")
}
}
You can set the contentMode either in the storyboard or in viewDidLoad. You don't need to keep setting it after updating an image.

Answer 4

let myBackgroundImage = UIImageView (frame: CGRect.zero)
override func viewDidLoad() {
super.viewDidLoad()
myBackgroundImage.image = UIImage(named: "wallpaper-1-iphone-8-plus.png")
myBackgroundImage.contentMode = UIViewContentMode.scaleAspectFill
self.view.addSubview(myBackgroundImage)
}
#IBAction func ButtonPressed(_ sender: Any) {
myBackgroundImage.image = UIImage(named: "wallpaper-2-iphone-8-plus.png")
}