iphoneiphone-sdk-3.0uiwebview

How can I scroll programmatically to the bottom in a UIWebView?


I know a similar question has been asked before but it seemed never been answered. I have a UIWebView and add some content by string. I use UIWebView because I add some images to it dynamically and also use other HTML features. This example code is simplified.

NSString *myHtmlString = @"SOME LONG TEST STRING 1234567890 123456789 0123456789 0123456789 0123456789 01234567890 WWWWWWWWWW WWWWWWWWWW WWWYYYYYYY YYYYYYYYYY YYYYYYYYYY YYYYYYYYYY YYYYYYYYYY YYYYYYYYY YYYYYYYWWW WWWWWWWWWW WWWWWWWWWW WWWXXXXXXX XXXXXXXXXX XXXZZZZZZZ THIS IS THE END I WANT TO SEE";
NSString *myPath = [[NSBundle mainBundle] bundlePath];
NSURL *myBaseURL = [NSURL fileURLWithPath:myPath];
[myWebView loadHTMLString:myHtmlString baseURL:myBaseURL];

What I want to see is the end of the string. I can scroll there, no problem. But I want to go there programatically.


Solution

  • This is fairly simple. First, you'll need to obtain height of the webpage:

    NSInteger height = [[webView stringByEvaluatingJavaScriptFromString:@"document.body.offsetHeight;"] intValue];
    

    Now you have the height of the document stored in the height variable. To scroll to bottom you have to use javascript again:

    NSString* javascript = [NSString stringWithFormat:@"window.scrollBy(0, %d);", height];   
    [webView stringByEvaluatingJavaScriptFromString:javascript];
    

    Of course you need to call them in proper moment. That is

    – webViewDidFinishLoad:(UIWebView *)webView
    

    method of your webview delegate.