Does iPhone/iPad UIWebView need to be active view to render?

Question

I need to render a web page offscreen to a bitmap, then show the bitmap to the user. Can this be done with simple code on the main thread like this:

NSString *urlAddress = @"http://www.google.com";
NSURL *url = [NSURL URLWithString:urlAddress];
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
[offscreenWebView loadRequest:requestObj];

Or do I need to attach the UIWebView to an active view?

In Android, the web view seems not to render unless it is part of an active view. So to do this task in Android, I need to create a view hierarchy, create an active view for the web renderer, and then put another view on top of it to let it draw offscreen.

score 5 · Accepted Answer · answered Mar 24 '12 at 17:32

5

I struggled with this problem for a while myself. UIWebView will not render unless it is added to a UIWindow object. However, this does not have to be the window you are using to show your app. You can make a separate UIWindow object, and attach the UIWebView to that and it will render just fine. However, UIWebView rendering is a slow process, so it will have a short delay before it is ready. When it is done, it will fire the webViewDidFinishLoad method to its delegate.

answered Mar 24 '12 at 17:32

borrrden

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This no longer seems to be the case on iOS 7.0 – Arie Litovsky Nov 12 '13 at 18:45
@diablosnuevos That is interesting to hear! I haven't needed to use this process in a long time so I haven't been keeping up with it. – borrrden Nov 13 '13 at 01:19
From some experimental evidence...it looks like it delays the rendering quite a bit. I'm still struggling to find the exact differences. – Arie Litovsky Nov 13 '13 at 12:19
Is this also true for WKWebView? – ninjaneer Apr 14 '15 at 01:39

Does iPhone/iPad UIWebView need to be active view to render?

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