Prevent caching of .css files in UIWebView loaded

问题:

In the iPad project I'm working on I've got a UIWebView inside of the app which displays a .html file which links to a .css file, i.e.

<link rel="stylesheet" href="style.css" type="text/css">

These files are stored locally on the iPad but are fetched from a remote server. I've noticed that UIWebView caches the .css file more or less indefinitely, and refuses to load the new file whenever I change it. I've once changed the name of the file just to get it to reset, but that's unacceptable in the long run.

Is there a way to prevent caching of the CSS file in a UIWebView? Or even better, is there a way to say when to cache and when not to?

回答1:

Yes.

Change your line to this:

<link rel="stylesheet" href="style.css?version=1" type="text/css">

Every time that you update the stylesheet, change the version. The browser will think that it is a different page because of the query string, and your server will ignore it.

If you are using a server side language such as PHP, you can also do the following:

<link rel="stylesheet" href="style.css?version=<?php echo time(); ?>" type="text/css">

This will change the version every time you refresh, thus stopping all caching.

回答2:

The better way that keeps your HTML markup and iOS code isolated is

[[NSURLCache sharedURLCache] removeCachedResponseForRequest:yourRequest];