倒计时

-(void)timeDeal{
    // 倒计时的时间 测试数据
    NSString *deadlineStr = self.model.follow_time;
    NSLog(@"deadlinStr=%@",deadlineStr);
    // 当前时间的时间戳
    NSString *nowStr = [self getCurrentTimeyyyymmdd];
    NSLog(@"nowStr=%@",nowStr);
    // 计算时间差值
    NSInteger secondsCountDown = [self getDateDifferenceWithNowDateStr:deadlineStr deadlineStr:nowStr];
    NSLog(@"secondsCountDown=%ld",secondsCountDown);
    __weak __typeof(self) weakSelf = self;
    
    if (_timer == nil) {
        __block NSInteger timeout = secondsCountDown; // 倒计时时间
        
        if (timeout!=0) {
            dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
            _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
            dispatch_source_set_timer(_timer, dispatch_walltime(NULL, 0), 1.0*NSEC_PER_SEC,  0); //每秒执行
            dispatch_source_set_event_handler(_timer, ^{
                if(timeout <= 0){ //  当倒计时结束时做需要的操作: 关闭 活动到期不能提交
                    dispatch_source_cancel(_timer);
                    _timer = nil;
                    dispatch_async(dispatch_get_main_queue(), ^{
                        weakSelf.FollowUpLabel.text = @"时间已到";
                    });
                } else { // 倒计时重新计算 时/分/秒
                    NSInteger days = (int)(timeout/(3600*24));
                    NSInteger hours = (int)((timeout-days*24*3600)/3600);
                    NSInteger minute = (int)(timeout-days*24*3600-hours*3600)/60;
                    NSInteger second = timeout - days*24*3600 - hours*3600 - minute*60;
                   // NSString *strTime = [NSString stringWithFormat:@"预警跟进 %02ld : %02ld : %02ld", hours, minute, second];
                    dispatch_async(dispatch_get_main_queue(), ^{
                        if (days == 0) {
                            weakSelf.FollowUpLabel.text = @"正常跟进";
                        } else {
                            NSString *followString = [NSString stringWithFormat:@"预警跟进 %ld天 %02ld : %02ld : %02ld", days, hours, minute, second];
                            NSMutableAttributedString *attrring = [[NSMutableAttributedString alloc] initWithString:followString];
                            [attrring addAttribute:NSForegroundColorAttributeName value:TEXT_COLOR_RED range:NSMakeRange(0, 4)];
                            self.FollowUpLabel.attributedText = attrring;
                        }
                        
                    });
                    timeout--; // 递减 倒计时-1(总时间以秒来计算)
                }
            });
            dispatch_resume(_timer);
        }
    }
}
//获取当前时间
- (NSString *)getCurrentTimeyyyymmdd {
    
    NSDate *now = [NSDate date];
    NSDateFormatter *formatDay = [[NSDateFormatter alloc] init];
    formatDay.dateFormat = @"yyyy-MM-dd HH:mm";
    NSString *dayStr = [formatDay stringFromDate:now];
    
    return dayStr;
}
//获取时间戳
- (NSInteger)getDateDifferenceWithNowDateStr:(NSString*)nowDateStr deadlineStr:(NSString*)deadlineStr {
    
    NSInteger timeDifference = 0;
    
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"yy-MM-dd HH:mm"];
    NSDate *nowDate = [formatter dateFromString:nowDateStr];
    NSDate *deadline = [formatter dateFromString:deadlineStr];
    NSTimeInterval oldTime = [nowDate timeIntervalSince1970];
    NSTimeInterval newTime = [deadline timeIntervalSince1970];
    timeDifference = newTime - oldTime;
    
    return timeDifference;
}