Having Fun at Bars

There are many other things that you can do with an app bar, just with the Android SDK, such as:

• Have checkable menu items, particularly for the overflow, that the user can check and uncheck
• Add other sorts of widgets to it, such as search fields and custom menus
• Have a “contextual action bar” that overlays the regular app bar with options tied to the UI state, such as providing actions for manipulating the current selected item(s) in a list
• Hide and show the app bar, so it does not take up screen space all the time (e.g., in a video player)

Other libraries can offer other features. For example, Google publishes the Material Components for Android library, which offers extensions like:

• Bottom app bars (i.e., an app bar that appears on the bottom, rather than the top)
• Collapsing toolbars (i.e., ones that appear super-sized at the outset, then collapse as the user scrolls through content)