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;
11     
12     // 获取计算出差值的日期组件
13     NSDateComponents *cmpt = [calendar components:unit fromDate:from toDate:self options:0];
14     return 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];
22     return 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];
31     return nowCmpt.year == selfCmpt.year
32     && nowCmpt.month == selfCmpt.month
33     && nowCmpt.day == selfCmpt.day;
34 }
35 
36 - (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];
42     return nowCmpt.year == selfCmpt.year
43     && nowCmpt.month == selfCmpt.month
44     && nowCmpt.day - selfCmpt.day == 1;
45 }
46 
47 @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];
            } else if (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";
            }
        } else if (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 {
 4     if (!_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;
10         
11         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;
16         
17         if (_type == ChaosTopicTypePicture) { // 图片
18             
19             // 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;
23             
24             // 判断图片是否过长
25             if (pictureH >= ChaosCellPictureMaxH) {
26                 self.bigPicture = YES;
27                 // 限制高度
28                 pictureH = ChaosCellPictureOverMaxH;
29             } else {
30                 self.bigPicture = NO;
31             }
32             
33             // 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     }
39     return _cellHeight;
40 }