倒计时功能实践 属性字符串

F3C993B5-1415-4F0F-B0E3-451AC2589D81.png

1 获取当前时间 和目标时间 计算相差多少
2 使用gcd 获取倒计时
3 属性字符串 设置 时分秒 的字体和背景色

{
    dispatch_source_t  _timer;
}

        NSString *deadlineStr = self.model.auction.endTime;
                
                NSString *nowStr = [NSString getCurrentTimeyyyymmdd];
                NSInteger secondsCountDown = [NSString getDateDifferenceWithNowDateStr:nowStr deadlineStr:deadlineStr];
                [self setdata:secondsCountDown];

- (void)setdata:(NSInteger)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(self->_timer);
                    self->_timer = nil;
                    dispatch_async(dispatch_get_main_queue(), ^{
//                        weakSelf.timeLabel.text = @"当前活动已结束";
                        weakSelf.headerView.titleLabel.text = @"已结束";
                    });
                } 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:@"距结束还有: %02ld 时 %02ld 分 %02ld 秒",hours, minute,second];
                    dispatch_async(dispatch_get_main_queue(), ^{
                        if (days == 0) {

//                          weakSelf.headerView.titleLabel.text = strTime;
                            
                            NSString *endstr =  strTime;
                                                    NSMutableAttributedString *mutablestr = [[NSMutableAttributedString alloc]initWithString:endstr];
                                                    NSDictionary *attris = @{NSForegroundColorAttributeName:[UIColor whiteColor],NSBackgroundColorAttributeName: ZHColor(140, 190, 250, 1),NSForegroundColorAttributeName:[UIColor whiteColor]};
                                                       [mutablestr setAttributes:attris range:NSMakeRange(7,2)];
                                                      [mutablestr setAttributes:attris range:NSMakeRange(12,2)];
                                                      [mutablestr setAttributes:attris range:NSMakeRange(17,2)];
                                                    weakSelf.headerView.titleLabel.attributedText = mutablestr;
                            
                        } else {

                            NSString *endstr =  [NSString stringWithFormat:@"距结束还有: %ld 天 %02ld 时 %02ld 分 ",days,hours, minute];
                            NSMutableAttributedString *mutablestr = [[NSMutableAttributedString alloc]initWithString:endstr];
                            NSDictionary *attris = @{NSForegroundColorAttributeName:[UIColor whiteColor],NSBackgroundColorAttributeName: ZHColor(140, 190, 250, 1),NSForegroundColorAttributeName:[UIColor whiteColor]};
                               [mutablestr setAttributes:attris range:NSMakeRange(7,2)];
                              [mutablestr setAttributes:attris range:NSMakeRange(12,2)];
                              [mutablestr setAttributes:attris range:NSMakeRange(17,2)];
                            weakSelf.headerView.titleLabel.attributedText = mutablestr;
                        }
                        
                    });
                    timeout--; // 递减 倒计时-1(总时间以秒来计算)
                }
            });
            dispatch_resume(_timer);
        }
    }
  
}