swift

mport UIKit

/// 控制定时器的类
class ZDTimerTool: NSObject {
    /// 定时器
//    private var timer: Timer?
    /// GCD定时器
    private var GCDTimer: DispatchSourceTimer?
    /// GCD定时器的挂起状态
    private var isSuspend: Bool = false
    override init() {
        super.init()
    }
    deinit {
        // 对象在销毁前会销毁定时器，所以使用定时器应该设置全局的属性
//        self.invaliTimer()
        self.invaliGCDTimer()
        DDLOG(message: "deinit: ZDTimerTool")
    }
}
/// GCD定时器相关方法
extension ZDTimerTool{
    /// 初始化得到GCD定时器
    func DispatchTimer(timeInterval: TimeInterval , handleBlock:@escaping (() -> Void)) {
        if self.GCDTimer == nil {
            self.GCDTimer = DispatchSource.makeTimerSource(flags: [], queue: DispatchQueue.main)
            self.GCDTimer?.schedule(deadline: DispatchTime.now(), repeating: timeInterval)
            self.GCDTimer?.setEventHandler{
                DispatchQueue.main.async {
                    handleBlock()
                }
            }
            self.GCDTimer?.resume()
            self.GCDTimer?.schedule(deadline: DispatchTime.now(), repeating: timeInterval)
        }else{
            self.stopOrResumeGCDTimer(isStop: false)
        }
        
        
        
    }
    /// 暂停或者重启GCDTimer
    func stopOrResumeGCDTimer(isStop: Bool){
        guard self.isSuspend != isStop else {
            return
        }
        isStop == true ? self.GCDTimer?.suspend() : self.GCDTimer?.resume()
        self.isSuspend = isStop
    }
    /// 销毁GCD定时器
    func invaliGCDTimer() {
        if self.isSuspend == true {
            self.GCDTimer?.resume()
        }
        self.GCDTimer?.cancel() //销毁前不能为suspend(挂起状态)
        self.GCDTimer = nil
    }
}

　　

2.使用

    //倒计时
    var countdownTimer = ZDTimerTool()

　　

适当地方开启定时器       
 countdownTimer.DispatchTimer(timeInterval: 1) { [weak self] in
            self?.handTimer()
        }

　　

    func handTimer() {
        if self.remainingSeconds == 0{
            self.remainingSeconds = 60
            self.sendButton.setTitle("重新发送", for: .normal)
            self.sendButton.backgroundColor = UIColor.init(hexColor: "FF8E00")
            self.sendButton.isEnabled = true
            self.countdownTimer.stopOrResumeGCDTimer(isStop: true)
            
        }else{
            sendButton.setTitle("(remainingSeconds)秒后重新获取", for: .normal)
            self.sendButton.backgroundColor = UIColor.gray
            sendButton.isEnabled = false
        }
        self.remainingSeconds -= 1
    }