Question

I want to create a simple web based application on Android that loads certain large files, like Javascript and user interface elements locally, from ‘assets’ directory. However I am unable to use local assets directory when loading external HTML. So the external server would give something like this:

<script type="text/javascript" src="file:///android_asset/javascript.js"/>

And WebView would use that, even if the website itself came from external website. I know there are security risks involved, but is there a way to perhaps do that by only allowing specific URL’s on applications end?

Is there any way I can do that?

Answer 1

First of all you have to copy all the assets somewhere (external storage, for instance).

Then, to filter URL’s you should override method

public boolean shouldOverrideUrlLoading(WebView view, String url);

in WebViewClient class.

added:
When your application starts, put the assets to /sdcard/somefolder/ see getExternalFilesDir()

in shouldOverrideUrlLoading override url to something like this

file:///sdcard/somefolder/<your filename here>

it should be as easy as

public boolean shouldOverrideUrlLoading(WebView view, String url) {
   url = "file://" + context.getExternalFilesDir().getAbsolutePath() + "/" + url;
   super.shouldOverrideUrlLoading(view, url);
}