根据实体类的属性，计算出要显示的高度，然后设置tableview代理

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    THDiaryEntry *entry = [self.fetchedResultsController objectAtIndexPath:indexPath];
    return [THEntryCell heightForEntry:entry];
}

THEntryCell.m :

+ (CGFloat)heightForEntry:(THDiaryEntry *)entry {
    const CGFloat topMargin = 35.0f;
    const CGFloat bottomMargin = 80.0f;
    const CGFloat minHeight = 106.0f;
    
    UIFont *font = [UIFont systemFontOfSize:[UIFont systemFontSize]];
    
    CGRect boundingBox = [entry.body boundingRectWithSize:CGSizeMake(202, CGFLOAT_MAX) options:(NSStringDrawingUsesFontLeading|NSStringDrawingUsesLineFragmentOrigin) attributes:@{NSFontAttributeName: font} context:nil];
    
    return MAX(minHeight, CGRectGetHeight(boundingBox) + topMargin + bottomMargin);
}

注，cellForRowAtIndexPath方法里最好不要太多的代码，把能抽取的代码都抽出来，比如设置属性以及显示在cell子类设置，看起来就清晰简洁的多了

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    THEntryCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
    
    THDiaryEntry *entry = [self.fetchedResultsController objectAtIndexPath:indexPath];
    [cell configureCellForEntry:entry];
    
    return cell;
}

THEntryCell.m:

- (void)configureCellForEntry:(THDiaryEntry *)entry {
    self.bodyLabel.text = entry.body;
    self.locationLabel.text = entry.location;
    
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"EEEE, MMMM d yyyy"];
    NSDate *date = [NSDate dateWithTimeIntervalSince1970:entry.date];
    
    self.dateLabel.text = [dateFormatter stringFromDate:date];
    
    if (entry.imageData) {
        self.mainImageView.image = [UIImage imageWithData:entry.imageData];
    } else {
        self.mainImageView.image = [UIImage imageNamed:@"icn_noimage"];
    }
    
    if (entry.mood == THDiaryEntryMoodGood) {
        self.moodImageView.image = [UIImage imageNamed:@"icn_happy"];
    } else if (entry.mood == THDiaryEntryMoodAverage) {
        self.moodImageView.image = [UIImage imageNamed:@"icn_average"];
    } else if (entry.mood == THDiaryEntryMoodBad) {
        self.moodImageView.image = [UIImage imageNamed:@"icn_bad"];
    }
    
    self.mainImageView.layer.cornerRadius = CGRectGetWidth(self.mainImageView.frame) / 2.0f;
    
    if (entry.location.length > 0) {
        self.locationLabel.text = entry.location;
    } else {
        self.locationLabel.text = @"No location";
    }
}

demo: https://github.com/Joeyechang/CoreDataDemo.git