Contextual action bar (CAB)

When the user does a multi-selection in the app, a top app bar turns into a contextual action bar, providing contextual actions for selected items. For instance, for selected sound files a contextual action bar with related functions will appear. 

Transformation to the contextual action bar changes:

• The color of the bar
• The navigation icon, replacing it with closing icon
• The heading of the bar with the text of CAB instead
• The list of top app bar actions, making them contextual