Dart constructors

Widgets are the central class hierarchy in the Flutter framework . A widget is an immutable description of part of a user interface.

The class Widget is the base class for the majority of user-interface objects . Widget adds support for receiving events from the browser and being added directly to panels.

Nearly all the code you write in Dart will be contained in classes. And a class is a blueprint for an object . That is, a class describes an object that you can create. The object itself is what holds any specific data and logic. For example, a Cat class might look like this: class Cat { String name; String color; }