I needed some clarity on navigation via device back button and up button.
The android app has a NewsFeed view, a Chats list view and a Chat window view. The app is minimized and user clicks on a chat push notification to go directly to the Chat window in the app. Back button will take user to NewsFeed view or should it minimize the app? According to Google Design guidelines the system Back button is used to navigate, in reverse chronological order, through the history of screens the user has recently worked with so following that it should minimize the app but I think it should not exit the user at this point but take them to News Feed and pressing the Back button subsequently would minimize the app.
And if the user presses Up button in chat window, it should take the user to Chat list view? In theory it makes sense but when I look at the following diagram in Google Design guidelines, it appears as if the device back button should also take the user to Chats list view.