Rotate image -45 degrees

Question

I am building example about FloatingButton.

But I have some troubles with rotate image. I want it to rotate like this link

https://github.com/yoavlt/LiquidFloatingActionButton

But my button is:

As you can see, when I click the first time, it run well :D, it transform like x, but when I click again, I want it back to original like +, but it doesn't work well.

Here is my code:

import UIKit

class ViewController: UIViewController {

    @IBOutlet var floatingButton: UIImageView!
    var floatingButtonIsActive = false

    override func viewDidLoad() {
        super.viewDidLoad()

        addShadowToFloatingButton()
        let gesture = UITapGestureRecognizer(target: self, action: #selector(floatingButtonTapped(_:)))
        floatingButton.addGestureRecognizer(gesture)
    }

    private func addShadowToFloatingButton() {
        floatingButton.layer.shadowColor = UIColor.grayColor().CGColor
        floatingButton.layer.shadowOffset = CGSize(width: -2, height: 2)
        floatingButton.layer.shadowOpacity = 1
        floatingButton.layer.shadowRadius = 1
    }

    func floatingButtonTapped(sender: UITapGestureRecognizer) {

        if floatingButtonIsActive == false {

            UIView.animateWithDuration(0.5, delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 5, options: .CurveEaseInOut, animations: {
                self.floatingButton.transform = CGAffineTransformMakeRotation(CGFloat(M_PI_4))
                }, completion: { _ in
                    self.floatingButtonIsActive = true
            })

        } else {
            UIView.animateWithDuration(0.5, delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 5, options: .CurveEaseInOut, animations: {
                self.floatingButton.transform = CGAffineTransformMakeRotation(CGFloat(-M_PI_4))
                }, completion: { _ in
                    self.floatingButtonIsActive = false
            })
        }
    }
}

Answer 1

Set the transform to CGAffineTransformIdentity when you are done. That is the transform that it originally had. When you set the transform, you are telling it the absolute angle to rotate to, regardless of what angle it is currently at.

func floatingButtonTapped(sender: UITapGestureRecognizer) {

    if floatingButtonIsActive == false {

        UIView.animateWithDuration(0.5, delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 5, options: .CurveEaseInOut, animations: {
            self.floatingButton.transform = CGAffineTransformMakeRotation(CGFloat(M_PI_4))
            }, completion: { _ in
                self.floatingButtonIsActive = true
        })

    } else {
        UIView.animateWithDuration(0.5, delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 5, options: .CurveEaseInOut, animations: {
            self.floatingButton.transform = CGAffineTransformIdentity
            }, completion: { _ in
                self.floatingButtonIsActive = false
        })
    }
}