Introduction to Enum Classes

In this chapter, we’re going to introduce the concept of enum classes. Let’s start with an example. Suppose that we’re implementing a payment method that has to support three possible options:

• Cash payment

• Card payment

• Bank transfer

Using enum values

The most basic way to represent a fixed set of values in Kotlin is an enum class. Inside its body, we list all the values, divided by a comma.

• We name values using UPPER_SNAKE_CASE notation (e.g., BANK_TRANSFER).

• Enum class elements can be referenced by the enum name, followed by a dot, and then the value name (e.g., PaymentOption.CASH).

• All values are typed as the enum class type.