Nsryjdtyk

I am new to iOS app development using Swift 4. I used the code below to change the image of button2 by running it in the iOS simulator:

 @IBAction func button2(_ sender: Any) {

     button2.setImage(UIImage(named: "wrong_answer"), for: .normal)

 }

However, button2 was highlighted when I first click on it without changing its image. Then after the second click, the image has been changed in button2.

My question is why the image was not changed in button2 after the first click?

What can I do to change the image after the first click instead of twice? Is this a bug in the iOS simulator of Xcode or it is normal?

You probably have an issue related to UIButton states that is causing this problem.
I don't think it is a simulator bug.
By the way, a good practice you should follow is to name the outlet different than the @IBAction. Let's say:

@IBAction func buttonTapped(_ sender: Any) {

  button.setImage(UIImage(named: "image"), for: .normal)

}

Try this:

override func viewDidLoad() {

  super.viewDidLoad()

  button.setImage(UIImage(named: "image"), for: .selected)

}



@IBAction func buttonTapped(_ sender: Any) {

  button.isSelected = !button.isSelected

}

And then the image will be updated automatically when you tap on the button. You can change it to button.isSelected = true if you want to keep the image after the first tap.

Rename your method/action so it differs from the button/property.

Change Any to UIButton since you know its class.

@IBAction func buttonTapped(_ buttonTapped: UIButton) {

  buttonTapped. button.isSelected = !button.isSelected

}

Make sure that you are receiving the button callbacks by declaring your view controller a UIButtonDelegate and set the button's delegate property to self.