An app bar has a number of uses:
- Displaying the app or activity name so that the user knows where in the app they are. As an example, an email app might use the app bar to indicate wheter the user is in their inbox or junk folder.
- Making key actions prominent in a way that’s predictable – for example, sharing content or performing searches.
- Navigation to other activities to perform an action.
To add a basic app bar, you need to use a theme that includes an app bar.