Dynamically set TableCell height based on Webview

Question

I'm struggling with adjusting the height of a UITableViewCell that contains a dynamically high WebView.

- (void) viewDidLoad {
  // ...
  for (ListItem *item in self.items) {
       UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectZero];
       [webView loadHTMLString:item.content baseURL:nil];
       [self.webViews addObject: webView]
  }
  // ...
  self.tableView.delegate = self;
  self.tableView.dataSource = self;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
   // try to calculate height?
   return 100.0;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
   ListItem *listItem = (self.items) [indexPath.row];
   [tableView registerNib:[UINib nibWithNibName:@"AccordionCell" bundle:nil] forCellReuseIdentifier:@"MyCustomCell"];
   CustomCell *cell = [tableView dequeueReusableCellWithIdentifier:@"MyCustomCell"];

   // [...] do something with cell

   UIWebView *webView = [self.webViews objectAtIndex: indexPath.row];
   webView.frame = CGRectMake(0, 0, cell.mainView.frame.size.width, 0);
   [cell.mainView addSubview: webView];
}

- (void)webViewDidFinishLoad:(UIWebView *)webView {
   NSString *height = [webView stringByEvaluatingJavaScriptFromString:@"document.getElementById('mainframe').offsetHeight;"];

   // [...] adjust height of web view by using the content's height
}

However, due to multiple threads the webViewDidFinishLoad always gets called after cellForRowAtIndexPath , and trying to adjust the cells height by changing its frame in the webViewDidFinishLoad did not succeed so far.

Answer 1

将这些高度存储在NSMutableArray方法中的webViewDidFinishLoad:方法中，然后最后重新加载UITableView的数据，并根据indexPath.Row在heightForRowAtIndexPath使用这些高度。

Answer 2

I don't want to mislead you, but if you need to print static HTML content into a view you can use a UILabel and an attributed string.

Like that :

NSMutableAttributedString *attributedString;
NSData *htmlData = [htmlString dataUsingEncoding:NSUTF8StringEncoding];
attributedString = [[NSMutableAttributedString alloc] initWithData:htmlData                                                        
                                                           options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType}
                                                documentAttributes:nil
                                                             error:nil];
someLabel.attributedText = attributedString;

If you use this, you don't need to wait for the WebView to load, you can use standard methods in order to calculate the height.