An Android WebViewClient that allows you inject your own JavaScript into WebViews on the client-side.

Get started
Put any scripts you have in assets/<dir_name>/<filename>
e.g

assets/scripts/my_script.js

Have a WebView with JavaScript enabled and a WebChromeClient to delegate to...

WebView webview = [....]; // initialize
webview.getSettings().setJavaScriptEnabled(true);
webview.setWebChromeClient(new WebChromeClient());

Load up your scripts

File script = AssetsUtil.getAssetFile(context, "scripts", "my_script.js"); // Catch IOExceptions!

Add them to your injector

WebViewInjectorClient client = WebViewInjectorClient();
client.appendScripts(script);

Add your injector to the WebView

webview.setWebViewClient(client);

Do whatever!

webview.loadUrl("http://www.example.com");

What's the license?
Apache v2

This is terrible
That's not a question.

A note from the author:
By using this, you're conceivably exposing yourself to XSS vulnerabilities.

Use your judgment.
Don't risk your customers data and privacy.
Eat your veggies.