Question

I am making use of the UIWebView to render some HTML. However, although the width of my webview is 320 my HTML is still shown full width and can be scrolled horizontally.

I want to achieve the same thing the native mail application achieves which is it fits all content within that width without zooming out – how does the native mail application render HTML like this?

Update

I thought making use of the viewport meta tag will help, but I couldn’t get this to work.

This is what is happening:

As you can see the content does not fit the device width. I’ve tried so many combinations of viewport meta tag. The below is an example of what happens when I try Martins suggestion.

Original HTML is can be found here.

The way this HTML is rendered by the native mail application is like so.

Answer 1

Here’s what you do:

In your UI controller that owns the web view, make it a UIWebViewDelegate.
Then where you set the URL to load, set the delegate as the controller:

NSString *urlAddress = @"http://dl.dropbox.com/u/50941418/2-build.html";
NSURL *url = [NSURL URLWithString:urlAddress];
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
[webView loadRequest:requestObj];  
webView.delegate = self;

And finally implement the webViewDidFinishLoad: to correctly set the zoom level:

This option will applicable from iOS 5.0 and >

- (void)webViewDidFinishLoad:(UIWebView *)theWebView
{
  CGSize contentSize = theWebView.scrollView.contentSize;
  CGSize viewSize = theWebView.bounds.size;

  float rw = viewSize.width / contentSize.width;

  theWebView.scrollView.minimumZoomScale = rw;
  theWebView.scrollView.maximumZoomScale = rw;
  theWebView.scrollView.zoomScale = rw;  
}

Option B, you can try to alter the HTML (this example does the job but is less than perfect from an HTML parsing standpoint. I just wanted to illustrate my point. It does work for your example, and probably most cases. The inset of 40 can probably be detected programmatically, I didn’t try to research that.

NSString *urlAddress = @"http://dl.dropbox.com/u/50941418/2-build.html";
NSURL *url = [NSURL URLWithString:urlAddress];

NSString *html = [NSString stringWithContentsOfURL:url encoding:[NSString defaultCStringEncoding] error:nil];
NSRange range = [html rangeOfString:@"<body"];

if(range.location != NSNotFound) {
  // Adjust style for mobile
  float inset = 40;
  NSString *style = [NSString stringWithFormat:@"<style>div {max-width: %fpx;}</style>", self.view.bounds.size.width - inset];
  html = [NSString stringWithFormat:@"%@%@%@", [html substringToIndex:range.location], style, [html substringFromIndex:range.location]];
}

[webView loadHTMLString:html baseURL:url];