Swift set button image

Question

When I try to change button's image when button pressed but it just shows a blue square as button's image

@IBAction func button(_ sender: Any) {
     buttonOutlet.setImage(#imageLiteral(resourceName: "thing"), for: UIControl.State.normal)
}

Answer 1

From Apple documentation:

A control becomes highlighted when a touch event enters the control’s bounds...

Highlighted state of a control

button.setImage(UIImage(named: "button_normal_state"), for: .normal)
button.setImage(UIImage(named: "button_pressed_state"), for: .highlighted)

Answer 2

Just recheck that you have "thing" - image in your target.

button.setImage(UIImage(named: "thing"), for: [.selected, .highlighted])

And see this question UIButton: set image for selected-highlighted state