Most iOS developers have used the fantastic UIView animateWithDuration family of functions. But there's another, slightly-lesser known static function on UIView that can help us transition like a pro. Let's check it out:

The function we'll be trying is transitionWithView. At first glance you'll see it's takes the same duration, options, and closures as its more-popular sister function.

However, instead of applying our changes over time, this function will (conceptually) take a snapshot of our view before and after the work in the animations** closure** is performed, then visually transition from the first snapshot to the second.

func flip() {
  flipped = !flipped

  UIView.transitionWithView(
    button,
    duration: 0.3,
    options: .TransitionFlipFromTop,
    animations: {
      self.button.setTitle(self.flipped ? "👎🏻" : "👍🏻", forState: .Normal)
    },
    completion: nil
  )
}

The type of transition depends on the animation option we pass in. We can do everything from simple cross-dissolves (fades), to fancy 3D flips. Super handy for simple transitions.

Download a sample project at j.mp/bite193. In it, we flip a thumbs up emoji using this incredibly simple technique.