将数据从XWalkView传递到Native Android

I have a question which may be simple for you guys. I'm running a WebApp using Crosswalk(XWalkView), everything looks smooth. I found out how to launch a native function from inside the website into my Android App.

public class WebAppInterface {
    @org.xwalk.core.JavascriptInterface
    public void callFunction() {
        onBuyGasButtonClicked(getCurrentFocus());

    }

I need to know how to pass data along with it. I'm using in-app-billing. I got their code samples and I think everything is going fine, but I need to update my PHP MySQL server with the amount purchased. How can I pass the variable to my Android App? (egs. email)

Let's assuming passing a string from JavaScript to native code. Firstly, create a JavaScript interface as you did:

public class WebAppInterface {
    @org.xwalk.core.JavascriptInterface
    public void callFunction(String text) {
    }
}

Then, add the interface to your XWalkView object:

mXWalkView.addJavascriptInterface(new WebAppInterface(), "testObject");

In your JavaScript:

function test(text) { testObject.callFunction(text); }