- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    // 如果要获取webView高度必须在网页加载完成之后获取

    // 方法一
    CGFloat height = [self.webView sizeThatFits:CGSizeZero].height;

    // 方法二
    CGFloat height = webView.scrollView.contentSize.height;

    // 方法三 （不推荐使用，当webView.scalesPageToFit = YES计算的高度不准确）
    CGFloat height = [[self.webView stringByEvaluatingJavaScriptFromString:@"document.body.offsetHeight"] floatValue];
}

- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    CGSize fittingSize = [self.webView sizeThatFits:CGSizeZero];
    self.height = fittingSize.height;
    self.webView.frame = CGRectMake(0, 0, fittingSize.width, fittingSize.height);

    // 用通知发送加载完成后的高度
    [[NSNotificationCenter defaultCenter] postNotificationName:@"WEBVIEW_HEIGHT" object:self userInfo:nil];
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    // 用于缓存cell高度
    self.heightDic = [[NSMutableDictionary alloc] init];

    // 注册加载完成高度的通知
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(noti:) name:@"WEBVIEW_HEIGHT" object:nil];
}

- (void)noti:(NSNotification *)sender
{
    TableViewCell *cell = [sender object];

    if (![self.heightDic objectForKey:[NSString stringWithFormat:@"%ld",cell.tag]]||[[self.heightDic objectForKey:[NSString stringWithFormat:@"%ld",cell.tag]] floatValue] != cell.height)
    {//先判断用于缓存的字典里没有相关的数据或者是和已缓存的数据不同再对新的cell高度数据进行缓存或者是更新
        [self.heightDic setObject:[NSNumber numberWithFloat:cell.height] forKey:[NSString stringWithFormat:@"%ld",cell.tag]];
//对相关的cell进行reload就OK了
       [self.tableView reloadRowsAtIndexPaths:@[[NSIndexPath indexPathForRow:cell.tag inSection:0]] withRowAnimation:UITableViewRowAnimationNone];
    }
}