How to determine UIWebView height based on content, within a variable height UITableView?

user_42404 0
Viewed 66072

I am trying to create a UITableView with variable height rows as explained in the answer to this question

My problem is each cell contains a UIWebView with different (statically loaded) content I can't figure out how to calculate the proper height based on the content. Is there a way to do this? I've tried things like this:

   (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
       WebViewCell *cell = (WebViewCell*)[self tableView:tableView cellForRowAtIndexPath:indexPath];
       [cell setNeedsLayout];
       [cell layoutIfNeeded];
       return cell.bounds.size.height;
    }

The cells themselves are loaded from a nib, which is simply a UITableViewCell containing a UIWebView. (It would also be fine if the cells just adjusted themselves to the largest of the html content, though variable height would be nicer).

uiwebview uitableview iphone cocoa-touch ios
7 Answers

This code is probably too slow for table view use, but does the trick. It doesn't look like there's any alternative, as UIWebView offers no direct access to the DOM.

In a view controller's viewDidLoad I load some HTML in a webview and when the load is finished run some javascript to return the element height.

- (void)viewDidLoad
{
    [super viewDidLoad];
    webview.delegate = self;
    [webview loadHTMLString:@"<div id='foo' style='background: red'>The quick brown fox jumped over the lazy dog.</div>" baseURL:nil];
}

- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    NSString *output = [webview stringByEvaluatingJavaScriptFromString:@"document.getElementById(\"foo\").offsetHeight;"];
    NSLog(@"height: %@", output);
}
user_756560

I was very glad to find your answers, the javascript trick worked well for me.

However, I wanted to say that there is also the "sizeThatFits:" method :

CGSize goodSize = [webView sizeThatFits:CGSizeMake(anyWidth,anyHeigth)];

We have to set a preferred size different from zero, but apart from that, it usually always works !

Usually, because with the UIWebViews, it seems to work only on the second loading (I use the "loadHTMLString:" method, and yes I call "sizeThatFits:" from the delegate "didFinishLoad:" method).

So, that's why I was very happy to find your solution which works in any case.

user_1130410

This seems to work. For now.

- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    CGFloat webViewHeight = 0.0f;
    if (self.subviews.count > 0) {
        UIView *scrollerView = [self.subviews objectAtIndex:0];
        if (scrollerView.subviews.count > 0) {
            UIView *webDocView = scrollerView.subviews.lastObject;
            if ([webDocView isKindOfClass:[NSClassFromString(@"UIWebDocumentView") class]])
                webViewHeight = webDocView.frame.size.height;
        }
    }
}

It should safely return 0 if it fails.

user_439900
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