Navigation in your android app via Up and Back button

Question

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.

Answer 1

It's mentioned clearly in the Google guidelines.

You can use Home screen widgets or notifications to help your users navigate directly to screens deep within your app's hierarchy. For example, Gmail's Inbox widget and new message notification can both bypass the Inbox screen, taking the user directly to a conversation view.

For both of these cases, handle the Up button as follows:

• If the destination screen is typically reached from one particular screen within your app, Up should navigate to that screen.

• Otherwise, Up should navigate to the topmost ("Home") screen of your app.

In the case of the Back button, you should make navigation more predictable by inserting into the task's back stack the complete upward navigation path to the app's topmost screen. This allows users who've forgotten how they entered your app to navigate to the app's topmost screen before exiting.

As an example, Gmail's Home screen widget has a button for diving directly to its compose screen. Up or Back from the compose screen would take the user to the Inbox, and from there the Back button continues to Home.

What this means is that if you open any app from widget or notification for eg take Gmail widget and you click on compose button, then this action takes user directly to the compose view bypassing the Conversation List. So in these types of cases clicking the Back button or the App Icon with the back symbol should take the user to the previous screen of the App, which is the Conversation List screen in this case.

Answer 2

In the case of the Back button, you should make navigation more predictable by inserting into the task's back stack the complete upward navigation path to the app's topmost screen.

This is just to make it more predictable. Apps like WhatsApp and Hangout do that. In fact those applications that minimize on back just because users arrived to that screen directly disorient the users.