直接看主要代码
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//截止日期
let endDate = datePicker.date
//开始日期
let startDate = Date()
//时间间隔
let timeInterval:TimeInterval = endDate.timeIntervalSince(startDate)
if timer == nil {
//剩余时间
var timeout = timeInterval
if timeout != 0 {
//创建全局队列
let queue = DispatchQueue.global()
//在全局队列下创建一个时间源
timer = DispatchSource.makeTimerSource(flags: [], queue: queue)
//设定循环的间隔是一秒,并且立即开始
timer?.scheduleRepeating(wallDeadline: DispatchWallTime.now(), interval: .seconds(1))
//时间源出发事件
timer?.setEventHandler(handler: {
//必须是当前日期往后的日期,在datePicker上也做了限制
if timeout <= 0 {
self.timer?.cancel()
self.timer = nil
DispatchQueue.main.async(execute: {
self.day.text = "00"
self.hour.text = "00"
self.minute.text = "00"
self.second.text = "00"
})
} else {
//计算剩余时间
let days = Int(timeout) / (3600 * 24)
if days == 0 {
self.day.text = ""
}
let hours = (Int(timeout) - Int(days) * 24 * 3600) / 3600
let minutes = (Int(timeout) - Int(days) * 24 * 3600 - Int(hours) * 3600) / 60
let seconds = Int(timeout) - Int(days) * 24 * 3600 - Int(hours) * 3600 - Int(minutes) * 60
//主队列中刷新UI
DispatchQueue.main.async(execute: {
if days == 0 {
self.day.text = "0"
} else {
self.day.text = "\(days)"
}
if hours < 10 {
self.hour.text = "0" + "\(hours)"
} else {
self.hour.text = "\(hours)"
}
if minutes < 10 {
self.minute.text = "0" + "\(minutes)"
} else {
self.minute.text = "\(minutes)"
}
if seconds < 10 {
self.second.text = "0" + "\(seconds)"
} else {
self.second.text = "\(seconds)"
}
})
timeout -= 1
}
})
//启动时间源
timer?.resume()
}
}
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DEMO效果图
原文链接：http://blog.csdn.net/feng2qing/article/details/56304809