Add widget/controls within gmail Ui like boomerang/streak

Question

I'm thinking of an idea to develop a widget lives within Gmail and do action on demand.

Like selecting a line of text clicking my button should create a task on a list (say asana.com)

I'm currently looking into https://developers.google.com/google-apps/gmail/contextual_gadgets

but wondering I'm heading right direction?

Check this one - http://www.streak.com/ they even have custom UI (in main view of gmail).

It would be really helpful if you share good resources and point the direction.

eg:

Answer 1

Gmail Contextual Gadgets (which work only in Google Apps Gmail, and not in "regular" @gmail.com Gmail) may not modify the Gmail UI - they are restricted to appearing in a rectangular area beneath a received message.

See www.wishery.com for an example.

To do the UI modification you illustrate, you must produce a browser extension - there are no native Google APIs to Gmail that'll help you (sadly!).

Answer 2

Also there are Sidebar Gadgets (for complex applications), like "Pipelines" of your screenshot.

Here you can find more info.

https://developers.google.com/google-apps/gmail/gadgets_overview