用nstimer实现倒计时代码,ObjC代码库,德仔网

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【ObjC】用nstimer实现倒计时
作者:昶福 / 发布于2014/11/6/ 620

	//
	[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timerFireMethod:) userInfo:nil repeats:YES];
	
	//
	- (void)timerFireMethod:(NSTimer *)theTimer
	{
	 BOOL timeStart = YES;
	 NSCalendar *cal = [NSCalendar currentCalendar];//定义一个NSCalendar对象
	 NSDateComponents *endTime = [[NSDateComponents alloc] init]; //初始化目标时间...
	 NSDate *today = [NSDate date]; //得到当前时间
	
	 NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
	 [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
	 NSDate *dateString = [dateFormatter dateFromString:todate];
	 NSString *overdate = [dateFormatter stringFromDate:dateString];
	// NSLog(@"overdate=%@",overdate);
	 static int year;
	 static int month;
	 static int day;
	 static int hour;
	 static int minute;
	 static int second;
	 if(timeStart) {//从NSDate中取出年月日，时分秒，但是只能取一次
	 year = [[overdate substringWithRange:NSMakeRange(0, 4)] intValue];
	 month = [[overdate substringWithRange:NSMakeRange(5, 2)] intValue];
	 day = [[overdate substringWithRange:NSMakeRange(8, 2)] intValue];
	 hour = [[overdate substringWithRange:NSMakeRange(11, 2)] intValue];
	 minute = [[overdate substringWithRange:NSMakeRange(14, 2)] intValue];
	 second = [[overdate substringWithRange:NSMakeRange(17, 2)] intValue];
	 timeStart= NO;
	 }
	
	 [endTime setYear:year];
	 [endTime setMonth:month];
	 [endTime setDay:day];
	 [endTime setHour:hour];
	 [endTime setMinute:minute];
	 [endTime setSecond:second];
	 NSDate *overTime = [cal dateFromComponents:endTime]; //把目标时间装载入date
	 //用来得到具体的时差，是为了统一成北京时间
	 unsigned int unitFlags = NSYearCalendarUnit| NSMonthCalendarUnit| NSDayCalendarUnit| NSHourCalendarUnit| NSMinuteCalendarUnit| NSSecondCalendarUnit;
	 NSDateComponents *d = [cal components:unitFlags fromDate:today toDate:overTime options:0];
	 NSString *t = [NSString stringWithFormat:@"%d", [d day]];
	 NSString *h = [NSString stringWithFormat:@"%d", [d hour]];
	 NSString *fen = [NSString stringWithFormat:@"%d", [d minute]];
	 if([d minute] < 10) {
	 fen = [NSString stringWithFormat:@"0%d",[d minute]];
	 }
	 NSString *miao = [NSString stringWithFormat:@"%d", [d second]];
	 if([d second] < 10) {
	 miao = [NSString stringWithFormat:@"0%d",[d second]];
	 }
	// NSLog(@"===%@天 %@:%@:%@",t,h,fen,miao);
	 [_longtime setText:[NSString stringWithFormat:@"%@天 %@:%@:%@",t,h,fen,miao]];
	 if([d second] > 0) {
	 //计时尚未结束，do_something
	// [_longtime setText:[NSString stringWithFormat:@"%@:%@:%@",d,fen,miao]];
	 } else if([d second] == 0) {
	 //计时结束 do_something
	
	 } else{
	//计时器失效
	 [theTimer invalidate];
	 }
	
	}
试试其它关键字
　nstimer　　倒计时　
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