iOS不得姐项目--精华模块上拉下拉的注意事项,日期显示,重构子控制器,计算cell的高度(只计算一次),图片帖子的显示

             1
            #import
            "
            NSDate+ChaosExtension.h
            "
             2
             3
            @implementation
             NSDate (ChaosExtension)

             4
             5 - (NSDateComponents *)deltaFromDate:(NSDate *)from
 6{
 7// 当前的日历对象 8     NSCalendar *calendar = [NSCalendar currentCalendar];
 9// 要获取的单元10     NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
1112// 获取计算出差值的日期组件13     NSDateComponents *cmpt = [calendar components:unit fromDate:from toDate:self options:0];
14return cmpt;
15}
16// 是否今年17 - (BOOL)isThisYear
18{
19     NSCalendar *calendar = [NSCalendar currentCalendar];
20     NSInteger nowYear = [calendar component:NSCalendarUnitYear fromDate:[NSDate date]];
21     NSInteger selfYear = [calendar component:NSCalendarUnitYear fromDate:self];
22return nowYear == selfYear;
23}
24// 是否是今天,年月日 都要比较25 - (BOOL)isToday
26{
27     NSCalendar *calendar = [NSCalendar currentCalendar];
28     NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay;
29     NSDateComponents *nowCmpt = [calendar components:unit fromDate:[NSDate date]];
30     NSDateComponents *selfCmpt = [calendar components:unit fromDate:self];
31return nowCmpt.year == selfCmpt.year
32     && nowCmpt.month == selfCmpt.month
33     && nowCmpt.day == selfCmpt.day;
34}
3536 - (BOOL)isYesterday
37{
38     NSCalendar *calendar = [NSCalendar currentCalendar];
39     NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay;
40     NSDateComponents *nowCmpt = [calendar components:unit fromDate:[NSDate date]];
41     NSDateComponents *selfCmpt = [calendar components:unit fromDate:self];
42return nowCmpt.year == selfCmpt.year
43     && nowCmpt.month == selfCmpt.month
44     && nowCmpt.day - selfCmpt.day == 1;
45}
4647@end

- (NSString *)create_time
{
    NSString *timeStr = nil;
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
    NSDate *date = [fmt dateFromString:_create_time];
    if (date.isThisYear) { // 今年if (date.isToday) { // 今天            
            NSDateComponents *cmpt = [[NSDate date] deltaFromDate:date];
            ChaosLog(@"%zd %zd %zd",cmpt.hour,cmpt.minute,cmpt.second);
            if (cmpt.hour > 1) { // 时间间隔 > 一小时
                timeStr = [NSString stringWithFormat:@"%zd小时前",cmpt.hour];
            } elseif (cmpt.minute > 1) { // 一小时 > 时间间隔 > 一分钟
                timeStr = [NSString stringWithFormat:@"%zd分钟前",cmpt.minute];
            } else { // 一分钟 > 时间间隔
                timeStr = @"刚刚";
            }
        } elseif (date.isYesterday) { // 昨天
            fmt.dateFormat = @"昨天 HH:mm:ss";
            timeStr = [fmt stringFromDate:date];
        } else { // 其他
            fmt.dateFormat = @"MM-dd HH:mm:ss";
            timeStr = [fmt stringFromDate:date];
        }
    } else { // 非今年
        timeStr = _create_time;
    }
    return timeStr;
}

             1
            //
             cell的高度
             2 - (CGFloat)cellHeight
 3{
 4if (!_cellHeight) {
 5 6// 文本框的Y值 7         CGFloat labelY = ChaosCellHeadImageH + 2 * ChaosMargin;
 8// 文本框的宽度 9         CGFloat labelW = [UIScreen mainScreen].bounds.size.width - 4 * ChaosMargin;
1011         CGSize size = CGSizeMake(labelW, CGFLOAT_MAX);
12// 文本框的高度 -- 重点 options要用对13         CGFloat labelH = [_text boundingRectWithSize:size options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName : [UIFont systemFontOfSize:14.0]} context:nil].size.height;
14// cell高度15         _cellHeight = labelY + labelH + ChaosCellBottomBarH + 2 * ChaosMargin;
1617if (_type == ChaosTopicTypePicture) { // 图片
1819// 计算图片显示的宽度20             CGFloat pictureW = labelW;
21// 计算图片显示的高度22             CGFloat pictureH = pictureW * self.height / self.width;
2324// 判断图片是否过长25if (pictureH >= ChaosCellPictureMaxH) {
26                 self.bigPicture = YES;
27// 限制高度28                 pictureH = ChaosCellPictureOverMaxH;
29             } else {
30                 self.bigPicture = NO;
31            }
3233// 计算图片的Y值34             CGFloat pictureY = labelY + labelH + ChaosMargin;
35             _pictureFrame = CGRectMake(ChaosMargin, pictureY, pictureW, pictureH);
36             _cellHeight = labelY + labelH + ChaosCellBottomBarH + 2 * ChaosMargin + pictureH + ChaosMargin;
37        }
38    }
39return _cellHeight;
40 }