Flutter and Dart Cookbook

Chapter 1. Learning Dart Variables

In this chapter, we focus on learning the basics of using variables in Dart. As you might expect, Dart offers a rich set of variable data types. To quickly get up to speed in the language, it is vitally important to know the basic data types.

If you are familiar with the use of variables in other programming languages, understanding variables in Dart should not be too difficult to grasp. Use this chapter as a quick guide to cement your understanding before moving on to more complex topics.

For beginners, this chapter will introduce you to the fundamentals. Ultimately it should offer a quick technical guide as you progress in your journey to learn Dart/Flutter.

Across the chapter, the code examples are self-contained and are focused on a typical use case. We start by discussing the four main variable types (i.e., int, double, bool, and String) and how each is used. Finally, we learn how to let Dart know what we want to do with our variables (i.e., final, const, and null).

We also cover the subject of immutability, which refers to the ability to change the value associated with a variable. An immutable variable is one that cannot be changed. In Dart, the keywords const and final make a variable immutable . A key nuance of immutability is whether the variable is checked at compile time or runtime. Compile time refers to checks applied at the code building stage (i.e., const variables). Runtime  refers to checks performed at the application execution ...