Detect when I scroll my UIWebView at top of the page

Question

I would like to add an URL/google bar on top of my webview, and access it by scrolling up my web page exactly as Safari do. To do this, I would detect when the user is scrolling the page, and more over when the scroll reaches the top.

But I really don't know how.

An idea ? Thanx a lot.

Martin

I've been digging around everywhere for this too, but haven't come across a decent answer yet. Have you found anything about this Martin? — bojo, Mar 04 '10 at 05:39

score 1 · Accepted Answer · answered Dec 06 '11 at 10:14

I was also digging for the same and found a solution. I coded the following method to detect the scrolling coordinates. See below:

-(void)userDidScrollWebView:(id)scrollPoint{
    // NSLog(@"scrolled:::");

    NSString *x1 = [webView stringByEvaluatingJavaScriptFromString: @"scrollX"];


    NSString *y1 = [webView stringByEvaluatingJavaScriptFromString: @"scrollY"];


    NSLog(@"scroll x=%@ y=%@", x1,y1);      

    if ([y1 isEqualToString: @"0"]) {
        NSLog(@"RELAOD ME");
    }   
}

Hope it helps you.

One year after, I succeded to log again ! It funny cause I used the same solution you preconize :) — Martin, Feb 07 '12 at 15:09

score 0 · Answer 2 · answered Jan 30 '10 at 05:37

0

Yep, you want to implement the UIScrollViewDelegate for your UIWebView.

answered Jan 30 '10 at 05:37

David Sowsy

1,680
14
13

But UIWebView does not implement the UIScrollViewDelegate ! There are already some discutions about, and they say that it's only possible with javascript... (http://stackoverflow.com/questions/1604795/scrolloffset-in-uiwebview) – Martin Feb 01 '10 at 15:39
1

Just a slight terminology nitpick: UIWebView *implements* UIScrollViewDelegate (it declares conformity to that protocol, after all). What you meant is that it doesn't *have* a UIScrollViewDelegate (and the appropriate setDelegate/delegate methods with which you could provide one -- which makes sense, because it is not a UIScrollView). – uliwitness Jun 29 '11 at 17:40
A quick check with [someWebView conformsToProtocol:@protocol(UIScrollViewDelegate)] shows that for all intents and purposes UIWebView is a UIScrollView. You have to write the methods to override the default behavior. – David Sowsy Jul 04 '11 at 13:14
Maybe David means you can subclass UIWebView and override UIScrollViewDelegate methods. It's a good way. Many developers get so used to delegation that they forget about subclassing. – javieralog Jan 18 '12 at 09:40

score 0 · Answer 3 · answered Jun 02 '10 at 17:58

You can use the following methods to solve your problem.

For getting the pageOffset:

int pageYOffset = [[webViewObj stringByEvaluatingJavaScriptFromString:@"window.pageYOffset"] intValue];

For getting the total scroll height of a webpage:

int scrollHeight = [[webViewObj stringByEvaluatingJavaScriptFromString:@"document.documentElement.scrollHeight"] intValue];

For scrolling the webpage to a particular offset:

[webViewObj stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"document.body.scrollTop = %d",scrollHeight ]];

Detect when I scroll my UIWebView at top of the page

3 Answers3

For getting the pageOffset:

For getting the total scroll height of a webpage:

For scrolling the webpage to a particular offset:

Linked