How to re-direct from HTML button to PayPal in Android..

How to re-direct from HTML button to PayPal in Android..

Hi there!
I'm quite new to Android SDK and Java, but I've used jQuery mobile to create a mobile online
shop inside Dreamweaver CS6, which, using the Phonegap build, works perfectly on iOS phone.

However, I have added a PayPal button using HTML code to each "product page" of index.html,
and I have now "wrapped" the index.html inside Java, and run it OK on the AVD emulator on
Android SDK inside Eclipse. (So far so good..!).

What I want to know is how to create a re-direct to a separate piece of Java code which starts with
the PayPal log-in page? I have run this as a separate PayPal app in Android, and using Sandbox, it
runs OK, but now I need to know how to re-direct from the PayPal checkout button inside index.html
 inside the "wrapper", to the PayPal Activity in Android??
Can anyone help, please, as I am quite new to Android SDK and Java?
I presume its some sort of Intent - but how do I get to that from an HTML button "wrapped" inside
Java??
Many thanks in advance!
David