How to refresh a UIWebView by a “pull down and rel

问题:

I know that this is possible in the Tweetie for iPhone or the xkcd iPhone app, but they are using a table. Any idea if this can be done for a simple UIWebView as well? I'm aware of the Javascript suggestions in this SO question, but what about making that natively?

回答1:

FYI, iOS 5 has officially introduced the property scrollView in UIWebView. I tested it. It worked perfectly with EGO's pull and refresh code. So the problem is no longer a problem for any iOS 5 devices.

For downward compatibility, you still need @CedricSoubrie's code though.

回答2:

To retrieve scroll events on UIWebView I personnaly use this code to get the scrollview that is inside the UIWebView :

- (void) addScrollViewListener
{
    UIScrollView* currentScrollView;
    for (UIView* subView in self.myWebView.subviews) {
         if ([subView isKindOfClass:[UIScrollView class]]) {
            currentScrollView = (UIScrollView*)subView;
            currentScrollView.delegate = self;
        }
    }
}

It's working. You can also use it to call [(UIScrollView*)subView setContentOffset:offSet animated:YES]; The only problem may be not to pass Apple code checking. I don't know yet since I'm still in coding phase.

Anyone tried that yet ?

回答3:

To tell the truth, UIWebVIew class has an undocumented getter method called _scrollView; So the code goes:

scrollView = [webView _scrollView];

回答4:

To get a reference for the UIScrollView in UIWebView, simply search it by iterating trough subviews.

for(id eachSubview in [webView subviews]){
        if ([eachSubview isKindOfClass:[UIScrollView class]]){
            scrollView = eachSubview;
            break;
        }
}

After that you can easily wire up things to your EGORefreshTableHeaderView interface with the UIWebView and the UIScrollView delegate callbacks.