我做了一个类似微博客户端的UITableView,自定义了UITableViewCell. 因为Cell中的图片异步加载,所以在图片加载完之后执行reloadRowsAtIndexPaths:withRowAnimation:来控制Cell高度. 但是,问题出现了,往上拉(从上往下)Cell正常,图片加载后,Cell高度更改.但是当往下拉(从下往上)的时候,Cell变化好奇怪,Cell下边有大片空白.thx a ton.请看图:

EDIT:而且,网上拉动太快的话,会crash

 *** Terminating app due to uncaught exception 'NSRangeException', reason: 

'*** -[__NSArrayM objectAtIndex:]: index 1 beyond bounds [0 .. 0]'

UPDATE:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    if(IS_LAST_ROW){
        return 40.0;
    }
    MStatusItem *status = [_data_array objectAtIndex:indexPath.row];
    CGFloat imageHeight = [[_imageHeights valueForKey:[NSString stringWithFormat:@"%@", status.ID]] floatValue];    

    CGFloat height = MAX([status.getPlainText sizeWithFont:[UIFont systemFontOfSize:16.0f] constrainedToSize:CGSizeMake(320.0f - (20.0f * 2), 20000.0f) lineBreakMode:NSLineBreakByWordWrapping].height, 44.0f)+ (20.0f * 1.5);
    height = [status hasImage] ? height + 50 + imageHeight: height + 40;
    if(status.rtweet != (id)[NSNull null]){
        NSString *retweetText = [status.rtweet valueForKey:@"text"];
        CGFloat retweetTextSize = MAX([retweetText sizeWithFont:[UIFont systemFontOfSize:16.0f] constrainedToSize:CGSizeMake(320.0f - (20.0f * 2), 20000.0f) lineBreakMode:NSLineBreakByWordWrapping].height, 44.0f)+ (20.0f * 1.5);
constrainedToSize:CGSizeMake(260.0, 2000.0f)];
        height += retweetTextSize;
        if(status.hasRetweetImage){
            height += imageHeight;
        }
    }
    return height;
}

imageHeights 是一个Dictionaray,保存加载出来的图片的高度.

tableView:cellForRowAtIndexPath:

__weak typeof(cell) weakCell = cell;
[cell.weiboImageView setImageWithURL:[NSURL URLWithString: status.tnpic]
                                placeholderImage:[UIImage imageNamed:@"placeholder.png"]completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType) {
                                    weakCell.weiboImageView.frame = CGRectMake(65.0, contentSize.height + 30.0f, image.size.width, image.size.height);
                                    [self.imageHeights setValue:[NSNumber numberWithFloat: image.size.height] forKey:[NSString stringWithFormat:@"%@", status.ID]];                            
                                        [tableView reloadRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationNone];

                                }
             ];

Cell 重用:

static NSString * ID = @"WeiboCustomCellIdentifier";
//[tableView registerClass:[WeiboCustomCell class] forCellReuseIdentifier:ID];
WeiboCustomCell *cell = [tableView dequeueReusableCellWithIdentifier:ID];
if(cell == nil){
        cell = [[WeiboCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:ID];
    }else{

        cell.textLabel.text = nil;
        while ([cell.contentView.subviews lastObject] != nil) {
            [(UIView*)[cell.contentView.subviews lastObject] removeFromSuperview];
        }
    }