要实现，点击 发送验证码 后，显示倒计时的60秒，每秒数字变化减少1。
搜：
swift click button count down
Swift NSTimer Tutorial – Lets create a Swift Timer (counter) application – iOS-Blog
最后代码如下：
let countdownTotalNum:Int = 60 var countdownCurNum:Int = 0 var countdownTimer:NSTimer startCountdown() func startCountdown() { print("startCountdown") self.countdownCurNum = self.countdownTotalNum updateCountdownLabel() self.countdownTimer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector:Selector("updateCountdown"), userInfo: nil, repeats: true) } func updateCountdown() { print("updateCountdown self.countdownCurNum=\(self.countdownCurNum)") self.countdownCurNum -= 1 if self.countdownCurNum <= 0 { self.countdownTimer.invalidate() self.countdownCurNum = 0 } updateCountdownLabel() } func updateCountdownLabel(){ print("updateCountdownLabel self.countdownCurNum=\(self.countdownCurNum)") dispatch_async(dispatch_get_main_queue(), { () -> Void in if self.countdownCurNum == 0 { self.verifySmsCodeButton.setTitle(self.strSendVerifyCode, forState:UIControlState.Normal) self.verifySmsCodeButton.enabled = true }else if self.countdownCurNum > 0 { self.verifySmsCodeButton.setTitle(String(self.countdownCurNum) + " 秒", forState:UIControlState.Normal) self.verifySmsCodeButton.enabled = false } }) } func stopCountdown(){ print("stopCountdown: self.countdownCurNum=\(self.countdownCurNum)") self.countdownTimer.invalidate() self.countdownCurNum = 0 updateCountdownLabel() } |
效果：
点击后开始倒计时：
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