How to connect List webpart and custom property of apppart?

Hi All,

I've created an apppart in SharePoint-Hosted app and would like to publish it on a page along with a webpart of a list (from Site Collection).

The both parts should be connected - when user select an item in list webpart the ID of the item needs to be passed to apppart and the latter updates its content.

The apppart has too custom properties: intID and sMode.

How to get an ID of selected item from one webpart and pass it to another apppart?

I tryed to use Filter but it does not see the custom properties of the apppart.

I need to use webpart of list to be able to kick off a workflow on a selected item. (I could not do it from SPHosted app unfortunately).

Thanks