Make a simple fade in animation in Swift?

Question

I am trying to make a simple animation in Swift. It is a fade in.

I attempted:

self.myFirstLabel.alpha = 0
self.myFirstButton.alpha = 0
         


        

Answer 1

0x7ffffff's answer is ok and definitely exhaustive.

As a plus, I suggest you to make an UIView extension, in this way:

public extension UIView {

  /**
  Fade in a view with a duration

  - parameter duration: custom animation duration
  */
  func fadeIn(duration duration: NSTimeInterval = 1.0) {
    UIView.animateWithDuration(duration, animations: {
        self.alpha = 1.0
    })
  }

  /**
  Fade out a view with a duration

  - parameter duration: custom animation duration
  */
  func fadeOut(duration duration: NSTimeInterval = 1.0) {
    UIView.animateWithDuration(duration, animations: {
        self.alpha = 0.0
    })
  }

}

Swift-3

/// Fade in a view with a duration
/// 
/// Parameter duration: custom animation duration
func fadeIn(withDuration duration: TimeInterval = 1.0) {
    UIView.animate(withDuration: duration, animations: {
        self.alpha = 1.0
    })
}

/// Fade out a view with a duration
///
/// - Parameter duration: custom animation duration
func fadeOut(withDuration duration: TimeInterval = 1.0) {
    UIView.animate(withDuration: duration, animations: {
        self.alpha = 0.0
    })
}

In this way you can do this wherever in your code:

let newImage = UIImage(named: "")
newImage.alpha = 0 // or newImage.fadeOut(duration: 0.0)
self.view.addSubview(newImage)
... 
newImage.fadeIn()

Code reuse is important!