Flutter is different from other frameworks because its UI
is built in code, not (for example) in an XML file or similar.
Widgets are the basic building blocks of a Flutter UI.
As you progress through this codelab,
you’ll learn that almost everything in Flutter is a widget.
A widget is an immutable object that describes a specific part of a UI.
You’ll also learn that Flutter widgets are composable, meaning
that you can combine existing widgets to make more sophisticated widgets.
At the end of this codelab,
you’ll get to apply what you’ve learned
into building a Flutter UI that displays a business card.

Estimated time to complete this codelab: 45-60 minutes.

Row and Column classes

Example: Creating a Column

The following example displays the differences between
  a Row and Column.

1. Click the Run button.