Swift实现iOS应用中短信验证码倒计时功能的实例分享

var sendButton: UIButton!

override func viewDidLoad() {
    super.viewDidLoad()

    sendButton = UIButton()
    sendButton.frame = CGRect(x: 40, y: 100, width: view.bounds.width - 80, height: 40)
    sendButton.backgroundColor = UIColor.redColor()
    sendButton.setTitleColor(UIColor.whiteColor(), forState: .Normal)
    sendButton.setTitle("获取验证码", forState: .Normal)
    sendButton.addTarget(self, action: "sendButtonClick:", forControlEvents: .TouchUpInside)

    self.view.addSubview(sendButton)
}

var remainingSeconds = 0

var remainingSeconds: Int = 0 {
    willSet {
        sendButton.setTitle("验证码已发送(/(newValue)秒后重新获取)", forState: .Normal)

        if newValue <= 0 {
            sendButton.setTitle("重新获取验证码", forState: .Normal)
            isCounting = false
        }
    }
}

var countdownTimer: NSTimer?

var isCounting = false {
    willSet {
        if newValue {
            countdownTimer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "updateTime", userInfo: nil, repeats: true)

            remainingSeconds = 10
            sendButton.backgroundColor = UIColor.grayColor()
        } else {
            countdownTimer?.invalidate()
            countdownTimer = nil

            sendButton.backgroundColor = UIColor.redColor()
        }

        sendButton.enabled = !newValue
    }
}

func updateTime(timer: NSTimer) {
     // 计时开始时，逐秒减少remainingSeconds的值
    remainingSeconds -= 1
}

 func sendButtonClick(sender: UIButton) {
    // 启动倒计时
    isCounting = true
}