Whats the Swift animate WithDuration syntax?

Dan Beaulieu picture Dan Beaulieu · Jun 23, 2015 · Viewed 29.1k times · Source

I'm porting an older app over to Xcode 7 beta and I'm getting an error on my animations:

Cannot invoke 'animateWithDuration' with an argument list of type '(Double, delay: Double, options: nil, animations: () -> _, completion: nil)'

Here's the code:

 UIView.animateWithDuration(0.5, delay: 0.3, options: nil, animations: {
      self.username.center.x += self.view.bounds.width
    }, completion: nil)

This works in Xcode 6 so I'm assuming this is an update in Swift. So my question is:

What's the Swift 3 syntax for animateWithDuration?

Answer

Dan Beaulieu picture Dan Beaulieu · Jun 23, 2015

Swift 3/4 Syntax

Here's an update with the Swift 3 Syntax:

UIView.animate(withDuration: 0.5, delay: 0.3, options: [.repeat, .curveEaseOut, .autoreverse], animations: {
    self.username.center.x += self.view.bounds.width
}, completion: nil)

If you need to add a completion handler just add a closure like so:

UIView.animate(withDuration: 0.5, delay: 0.3, options: [.repeat, .curveEaseOut, .autoreverse], animations: {
    // animation stuff      
}, completion: { _ in
    // do stuff once animation is complete
})

Old Answer:

It turns out it's a very simple fix, just change options: nil to options: [].

Swift 2.2 Syntax:

UIView.animateWithDuration(0.5, delay: 0.3, options: [], animations: {
      self.username.center.x += self.view.bounds.width
    }, completion: nil)

What changed?

Swift 2 got rid of the C-Style comma-delimited list of options in favor of option sets (see: OptionSetType). In my original question, I passed in nil for my options, which was valid prior to Swift 2. With the updated syntax, we now see an empty option list as an empty set: [].

An example of animateWithDuration with some options would be this:

 UIView.animateWithDuration(0.5, delay: 0.3, options: [.Repeat, .CurveEaseOut, .Autoreverse], animations: {
      self.username.center.x += self.view.bounds.width
    }, completion: nil)