需求是实现一个倒计时抢单功能，为了准确起见，倒计时到最后时需要验证服务器，重新获取服务器时间调整倒计时，我自己分装了一个显示倒计时的Label，当然为了实现时间的校准和倒计时结束后，UI界面的调整，涉及到了代理去实现这些功能。
先看效果图：
声明代理方法
// 声明设置代理方法
protocol PreviewCountdownLabelDelegate : class {
func PreviewCountdownLabelExhaust()
func PreviewCountdownLabelCorrectTime()
}
class PreviewCountdownLabel: UILabel {
static let preTimeFormatter = NSDateFormatter(dateFormat: "HH:mm:ss")
var isFirst = 0
weak var delegate : PreviewCountdownLabelDelegate?
let timet = NSDate().timeIntervalSinceDate(NSDate().dateByAddingTimeInterval(16 * 60 * 60))
var expectedTime = NSDate() {
didSet {
}
}
var timeExpectedTime = NSDate() {
didSet {
}
}
var showChinese = false
var timer : NSTimer!
init() {
super.init(frame: CGRectZero)
FUCKINIT()
}
override init(frame: CGRect) {
super.init(frame: frame)
FUCKINIT()
}
func FUCKINIT() {
textColor(UIColor.whiteColor())
textAlignment(.Right)
font(systemFontOfSize: 20)
timer = NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, selector: "timePass", userInfo: nil, repeats: true)
timer.fire()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func timePass() {
let _time = NSDate().timeIntervalSinceDate(expectedTime)
let timeIsOut = _time >= 0
ccRight(_time)
if Int(-_time) == 300 {
delegate?.PreviewCountdownLabelCorrectTime() //当倒计时还剩余五分钟时，去服务器重新获取时间，校准倒计时时间
}
if timeIsOut {
font(UIFont(name: "Quartz-Regular", size: 20)!)
text("00:00:00")
guard isFirst == 0 else {
timer.invalidate()
delegate?.PreviewCountdownLabelExhaust() //当倒计时完成后走这个代理方法，去改变布局UI
return
}
isFirst = 1
} else {
let time = NSDate(timeIntervalSince1970: 0).dateByAddingTimeInterval(-_time - timet)
let str = PreviewCountdownLabel.preTimeFormatter.stringFromDate(time)
font(UIFont(name: "Quartz-Regular", size: 20)!)
text("\(str)")
}
}
}
然后在需要实现代理方法的类中去遵守代理协议，实现代理方法
MARK: - Methods
extension TaskDetailViewController {
func closeButtonClick() {
dismissViewControllerAnimated(true, completion: nil)
}
func askTaskInfo() {
API.taskDetail(self.taskID) { task in
ccRight(self.taskID)
self._task = task
self.discountRateL.text(task.selfBuyOff.string)
self.addressL.text(task.areaDisplayName)
self.priceL.text(task.price.string)
self.commissionL.text(task.shotFee.string)
self.orderNameLabel.text(task.title)
self.requisitionLabel.text(task.shortDescription)
self.imageURL = task.imageURLString
self.imageView.kf_setImageWithURL(task.imageURLString.URL, placeholderImage: AppStyle.PlaceHolderImage)
self.displayStatus = task.relation
let time1 = NSDate(jsonDate: "/Date(" + task.databaseTime + "+0800)/")
let time2 = NSDate(jsonDate: "/Date(" + task.futurePublishTime + "+0800)/")
let time = NSTimeInterval(task.diffTime)
ccRight(time1)
ccRight(time2)
if task.isTimerTask == .YES {
if time > 0 {
if self.countDownLabel == nil {
self.countDownLabel = PreviewCountdownLabel()
.superView(self.view)
.width(98)
.bottom(170 + 49 + 5)
.right(12)
.height(28)
.backgroundColor(UIColor.blackColor().alpha(0.5))
.textAlignmentCenter()
.cornerRadius(6)
}
self.countDownLabel!.delegate = self
self.countDownLabel!.hidden = false
self.countDownLabel!.expectedTime = NSDate().dateByAddingTimeInterval(time! / 1000)
}
// 预览 查看任务要求（倒计时完后，显示抢单，可选择继续抢单，或者跳转H5查看任务要求）
switch task.isCustomTask {
case .No:
self.getOrderButton.title("预览")
self.getOrderButton.removeTarget(self, action: "getOrderButtonClick", forControlEvents: UIControlEvents.AllEvents)
self.getOrderButton.removeTarget(self, action: "PreviewAction", forControlEvents: UIControlEvents.AllEvents)
self.getOrderButton.target(self, upInsideAction: "PreviewAction")
self.getOrderButton.enabled(true)
AnimateWithDuration(0.15) {
self.getOrderButton.backgroundColor(AppStyle.Tint)
}
ccRight("不是")
case .Yes:
self.getOrderButton.title("查看任务要求")
self.getOrderButton.removeTarget(self, action: "getOrderButtonClick", forControlEvents: UIControlEvents.AllEvents)
self.getOrderButton.removeTarget(self, action: "PreviewAction", forControlEvents: UIControlEvents.AllEvents)
self.getOrderButton.target(self, upInsideAction: "PreviewAction")
self.getOrderButton.enabled(true)
AnimateWithDuration(0.15) {
self.getOrderButton.backgroundColor(AppStyle.Tint)
}
ccRight("是")
}
}else {
self.getOrderButton.title("抢单")
if task.relation == Task.RelationToToken.Accepted || task.isDirect == Task.DirectionalPush.Yes{
self.getOrderButton.removeTarget(self, action: "getOrderButtonClick", forControlEvents: UIControlEvents.AllEvents)
self.getOrderButton.removeTarget(self, action: "PreviewAction", forControlEvents: UIControlEvents.AllEvents)
self.getOrderButton.target(self, upInsideAction: "getOrderButtonClick")
self.getOrderButton.enabled(true)
AnimateWithDuration(0.15) {
self.getOrderButton.backgroundColor(AppStyle.Tint)
}
}else {
if task.relation == Task.RelationToToken.UnAccepted || task.relation == Task.RelationToToken.Finished {
self.getOrderButton.enabled(true)
AnimateWithDuration(0.15) {
self.getOrderButton.backgroundColor(AppStyle.GrayTextColor)
}
}
}
}
}
}
初始化好了自定义倒计时Label，设置好代理然后实现协议方法：
MARK: - PreviewCountdownLabelDelegate
extension TaskDetailViewController : PreviewCountdownLabelDelegate {
func PreviewCountdownLabelCorrectTime() {
askTaskInfo()
}
func PreviewCountdownLabelExhaust() {
self.countDownLabel!.hidden = true
self.countDownLabel!.timer.invalidate()
askTaskInfo()
}
}