Animate Rotating UIImageView

Question

I want to rotate a UIImageView by roughly 10 degrees left/right but have a smooth animation, rather than a sudden turn which I see using:

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Answer 1

A modern Swift solution, using NSTimer and CGAffineTransformMakeRotation:

class Rotation: UIViewController {
    var timer = NSTimer()
    var rotAngle: CGFloat = 0.0

    @IBOutlet weak var rotationImage: UIImageView!

    override func viewDidLoad() {
      super.viewDidLoad()
      activateTimer()
    }

    func activateTimer() {
      //(1)
      timer = NSTimer.scheduledTimerWithTimeInterval(1.0, target:self, selector:#selector(Rotation.updateCounter), userInfo: nil, repeats: true) 
    }

    func updateCounter() {
      //(2)
      var rotateLeft: Bool = true
      if rotateLeft {
        rotAngle -= 30.0
      } else {
        rotAngle += 30.0
      }
      //(3)
      UIView.animateWithDuration(2.0, animations: {
        self.rotationImage.transform = CGAffineTransformMakeRotation((self.rotAngle * CGFloat(M_PI)) / 180.0)
      })
    }
}

Things to notice:

• Connect the outlet the the UIImageView

• Play with the (1)timer pace, (2)animation pace and (3)rotation angle to get the desired results. This set of variables worked for me.