What is the difference between primaryColor and primarySwatch in Flutter?

Question

In Flutter, one can apply a theme to the app using ThemeData class. But there two propeties of this class that confuses me: primaryColor and primarySwatch

Answer 1

primarySwatch is not a Color. It's MaterialColor. Which means it's a the different shades of a color a material app will use.

primaryColor is one of those shades. To be exact, primaryColor is normally equal to primarySwatch[500].

It is usually better to define a primarySwatch instead of primaryColor. Because some material components may use a different shade of the primaryColor for things such as shadow, border, ...