How to pop up Flex Panel by clicking on a GWT(or GXT) component?

I have a we开发者_如何学Cb-application whose UI is implemented in GXT (ext GWT).

Now I want to switch to Flex but as the application is so large that I cannot afford to start migrating the whole application at once.

So I have decided to migrate slowly. So what I want is to bring up a Flex panel on the click of a GXT's button.

Basically the idea is how to make Flex components listen to the events generated by GXT's component.

Flex app is ultimately an SWF and GWT gives you JavaScript; you can use ExternalInterface to invoke an SWF's methods from JavaScript code and vice-versa. Checkout the addCallback method - the linked page has some sample code in it.