ios 倒计时

http://stackoverflow.com/questions/10663184/implementing-a-countdown-timer-in-objective-c

http://stackoverflow.com/questions/17145112/countdown-timer-ios-tutorial

iOS Countdown Timer To Specific Date

UITableViewCell countdown UILabel not updating

Multiple countdown timer in uitableviewcell not working

Using timer in a tableview re creates the timer after any scroll or table reload

Manage countdown timer for each UITableViewCell