I want to integrate Google Assistant in my app. I am not just for launching the the app, also to operate on it like below:
App: Hi! What are you looking for? User: T-shirts App: What is the size? User: 40 App: What is the color? User: Any / Red and blue App: Here is the T-shirts for you User: Show order by Popularity App: Here it is.
Is it possible to do so by Google Assistance? Is it possible to start any activity of my app with proper intent extra?
With Actions on Google as you will need to build a server side components to handle the voice/chat interaction. For an example of the voice interaction see: https://developers.google.com/actions/extending-the-assistant
As to actually starting an app from Google Assistant. I don't believe there is a direct way.
Alternatively that seems to be possible for a select set of voice commands through Google Search Voice Actions to reach your app.
Note that Google isn't taking any more requests for custom Voice Actions:
https://developers.google.com/voice-actions/custom-actions
And that the pages doesn't seem to have been updated since 2015 so I'm unclear what is still supported or not.
From what I can tell the only part of Google Search Voice Actions that may be still around in 2017 is the ability to incorporate app data into Google Search via Firebase App Indexing
