A Toolbar is a widget based generalization of action bars for use within layouts.
The Toolbar was introduced in Android 5.0 Lollipop however it was also added to Added to appcompat-v7:21.0.0 for backwards compatibility. The widget consists of a navigation button, a title and subtitle, one or more custom views and an action menu. You should use Toolbar instead of Actionbar when you want to use the Actionbar features but you require more control over it's appearance, if you want multiple Actionbars, or if you want Actionbars that only take up part of the width of the screen.
For more information:
- Documentation for Toolbars added in Lollipop
- Documentation for the support library implementation
- Tutorial from Vogella
See also: