How to improve UIWebView scrolling performance?

Question

It seems to be really hard to improve the performance of a UIWebView, especially for websites like Mashable or Ars Technica, where tons of scripts are loaded and long, multi-pag

Answer 1

I'm afraid there isn't. Big websites remain big and hence consume lots of memory.

I'd argue against Brad Larson: backing a webview in a own CATiledLayer is technically possible (just do [webView.layer renderInContext: ]) but does not make a lot of sense. Tiled layers load lazily, as do web views. You'd need a enormous amount of finetuned code to detect when the page finished loading, then to cache things into your tiled layer and so on.

Despite that, the webview is actually quite optimized. I'd even argue that it's one of the best-optimized things in the whole iOS. It's the single-most-used performance critical component across the whole platform. Every multi-line text is a webview (UITextView is implemented using them, e.g). If the webview breaks on some website, you'll have quite a hard time making it faster.

There are cases where a different solution might work as well, but only if you're looking for something special purpose. If you're not, then leave your hands off and invest the time somewhere else. Just my 2 cent...

Answer 2

Some web browser applications like iCab and Atomic Web Browser seem to use the _setDrawInWebThread: method, and clearly they are allowed in the app store. If they are not using this method, then they are using something that works identically to it for their UIWebViews. Does anyone know for sure Apple is rejecting apps that use this private API? Could they be letting that one go by "silently"? I'm surprised Apple hasn't made this a public API by now, because any application that uses a UIWebView to display a web page (and there are many high profile apps that do this, FlipBoard for example) makes the device look 'choppy' and sub-par performing...

Answer 3

I don't really know if this can help or is accurate given the question, but here is what I have to say:

Some properties like shadow or gradient, and even images inside the WebView affects a lot the performances you can get. Try not to use them and/or to keep them as few as possible.