IOS开发代码分享之用nstimer实现倒计时功能-华尔子博-奥夏网

用nstimer实现倒计时功能，废话不多说，直接上代码，详细解释请参照注释

//

[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];

}

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