Cart button in android application.
<p>This is a general question. I could not get any answer for this on the Google, so asking on the stackoverflow.</p>

<p>Some of the android apps have cart button at the top of the activity(action bar).
For example I have attached an image of amazon android application.
All the products would be listed through <code>webview</code> and when the user places order on amazon an order cart updates with the number from 0 to 1 which is in action bar.
This updation is happening in android from <code>webview</code> to some widget used in android most probably.</p>

<p>Could anyone let us know how this could be achieved or totally the whole activity itself is <code>webview</code>? I want to know what widget are they using and how are they updating the cart in the activity.</p>

<p>Any pointers to examples would be really helpful.</p>

<p>Attached is the image of amazon android application screen.</p>

<p><img src="http://i.stack.imgur.com/otDhp.png" alt="Image of the amazon android application"></p>

<p>thanks.</p>
