Listen to when custom tabs closes

[KingIdee]

Is there a way of knowing when the user has selected done or cancel in the chrome tab or better still, is there a way to close the tab manually?

[prologikus]

For closing the tabs, you can use:
CustomTabsPlatform.instance.closeAllIfPossible()

For knowing when the action is done, you need to have control of the website you're in, and call an API from the website to inform the app that the action is done.