1 获取UIWebView高度

- (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];
}

2 UIWebView加载完成后cell高度的更新,使用通知来实现。

TableViewCell.m

- (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];
}

ViewController.m

- (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)
    {
        [self.heightDic setObject:[NSNumber numberWithFloat:cell.height] forKey:[NSString stringWithFormat:@"%ld",cell.tag]];
       [self.tableView reloadRowsAtIndexPaths:@[[NSIndexPath indexPathForRow:cell.tag inSection:0]] withRowAnimation:UITableViewRowAnimationNone];
    }
}