AppBar widget lets you pass in widgets for the

leading widget, and the

actions of the

title widget.
This pattern recurs throughout the framework and is something you
might consider when designing your own widgets.

For more information, see Material Components widgets.

Note:
  Material is one of the 2 bundled designs included with Flutter.
  To create an iOS-centric design,
  see the Cupertino components package,
  which has its own versions of
  CupertinoApp, and CupertinoNavigationBar.

Handling gestures

Most applications include some form of user interaction with the system.
The first step in building an interactive application is to detect
input gestures. See how that works by creating a simple button: