Executing simple code on android app before closing

Executing simple code on android app before closing

Hello, I've been trying to integrate airpush in andriod but I've been
having some issues.
@Override public boolean onKeyDown(int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_BACK) && mWebView.canGoBack()) {
mWebView.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
As you can see is the andriod go back code for webview via history.
The problem is that I want execute this code when it has no more history,
meaning when the application is about to close.
airpush.startLandingPageAd();
Any help will be greatly appreciated guys :)..