SwiftでUIButtonのタップ時に押された感のアニメーション

タップしたかどうかはtouchesBeganなどを使います。

下記はtouchesBeganした時に、
「ボタンがわずかに縮小し、alphaが若干薄くなる」
というUIButtonを継承したクラスを作ってみました。

import UIKit

class UIButtonAnimated: UIButton {
    
    override init() {
        super.init()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
    }
    
    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
        super.touchesBegan(touches, withEvent: event)
        self.touchStartAnimation()
    }
    
    override func touchesCancelled(touches: NSSet!, withEvent event: UIEvent!) {
        super.touchesCancelled(touches, withEvent: event)
        self.touchEndAnimation()
    }
    
    override func touchesEnded(touches: NSSet, withEvent event: UIEvent) {
        super.touchesEnded(touches, withEvent: event)
        self.touchEndAnimation()
    }

    private func touchStartAnimation(){
        UIView.animateWithDuration(0.1,
            delay: 0.0,
            options: UIViewAnimationOptions.CurveEaseIn,
            animations: {() -> Void in
                self.transform = CGAffineTransformMakeScale(0.95, 0.95);
                self.alpha = 0.7
            },
            completion: nil
        )
    }
    private func touchEndAnimation(){
        UIView.animateWithDuration(0.1,
            delay: 0.0,
            options: UIViewAnimationOptions.CurveEaseIn,
            animations: {() -> Void in
                self.transform = CGAffineTransformMakeScale(1.0, 1.0);
                self.alpha = 1
            },
            completion: nil
        )
    }

}

利用するときは普通のUIButtonと同じく

let btn = UIButtonAnimated(frame: CGRectMake(0, 0, 100, 100))

という感じで使えばOKです。