Question

HI, I have an @override that I use in native Android that scrolls the webView(scrollView)using the device volume keys. This is a real nice feature for the user when he/she is using one hand. I would like to use it with Phonegap. Obviously I cant use the: WebView scrollView = (WebView) findViewById(R.id.ch01); So How can I use/implement feature with Phonegap or pass the function w/to jQuery??

Some code will be helpful – I am on a tight learning curve with jQ & Phonegap. Thnx!

This is the override I use:

    @Override
// --------------- Set the Device Volume Keys to Scroll the WebView -->
public boolean dispatchKeyEvent(KeyEvent event) {
    int action = event.getAction();
    int keyCode = event.getKeyCode();
    WebView scrollView = (WebView) findViewById(R.id.ch01);
    switch (keyCode) {
    case KeyEvent.KEYCODE_VOLUME_UP:
        if (action == KeyEvent.ACTION_DOWN) {
            scrollView.pageUp(false);
        }
        return true;
    case KeyEvent.KEYCODE_VOLUME_DOWN:
        if (action == KeyEvent.ACTION_DOWN) {
            scrollView.pageDown(false);
        }
        return true;
    default:
        return super.dispatchKeyEvent(event);
    }
}

Answer 1

The easiest, quickest way to do this would be to extend the onKeyDown method override in DroidGap.java. Add a few cases to the conditional, catching the volume keys, and using the same approach you see that exists in this method, you can directly invoke JavaScript by calling something like:

this.appView.loadUrl("javascript:alert('hello world!');");

Of course, you would probably change the alert call to something else specific to your application, or perhaps even directly calling window.scrollBy to do the scrolling.

A better, more modular approach would be to encapsulate this functionality into a PhoneGap plug-in. You could then contribute it back to the community as I’m sure others would appreciate and make use of this as well! 😉