Is it possible to change the context of a WebView after it has been instantiated?

You can try to create the WebView with a MutableContextWrapper:

MutableContextWrapper mMutableContext=new MutableContextWrapper(context);
WebView mWebView=new WebView(mMutableContext);

and later on you could do

mMutableContext.setBaseContext(newcontext);

But ...

• WebView is a very complex component that will probably be using the passed context to create other objects like Handlers. WebView probably uses those handlers to post stuff to the original UI thread, so at the end you'll probably have a View with a mix of contexts, you know, a double memory leak (if it ever works properly)

• Webview spans at least 1 thread "webcore" that is where the action happens and is also in constant communication with the original UI thread with ... handlers? through the original context? who knows!

• There are even 2 different webview engines: Kitkat is chromium-based while jelly bean and previous versions use AOSP/WebView. So you have an additional breaking point.

• The reasons you state are not strong enough imho. WebView is not that slow. If the app you load is, try to optimize it. There are a lot of things you can do for that, like loading the HTML & graphics from internal assets.