createHeartButton.swift

private func setupButton() {
    let heartImage = UIImage(named: "heart")
    self.heartButton = UIButton(frame: CGRectZero)
    self.heartButton.frame.size = CGSizeMake(heartImage!.size.width, heartImage!.size.height)
    self.heartButton.center = self.view.center
    self.heartButton.setImage(heartImage, forState: .Normal)
    self.heartButton.addTarget(self, action: "performHeartBeat:", forControlEvents: .TouchUpInside)
    self.view.addSubview(self.heartButton)
}