Enum in Kotlin

An enum in Kotlin is a special type that represents a group of related constants. It allows you to define a fixed set of values for a variable. Enum constants are typically used to represent a closed set of options or choices.

To define an enum in Kotlin, you use the enum class keyword, followed by the name of the enum and the list of constant values inside curly braces. For example:

enum class Color {
    RED, GREEN, BLUE
}

In the above example, the Color enum has three constants: RED, GREEN, and BLUE.

Enums in Kotlin can also have properties and methods, similar to classes. Each enum constant can have its own values for these properties. For example:

enum class Color(val rgb: Int) {
    RED(0xFF0000),
    GREEN(0x00FF00),
    BLUE(0x0000FF)
    
    fun description(): String {
        return when (this) {
            RED -> "Red color"
            GREEN -> "Green color"
            BLUE -> "Blue color"
        }
    }
}

In the above example, the Color enum has an additional property rgb associated with each constant. It also has a method description() that provides a textual description of each color.

To access the properties and methods of an enum constant, you simply use dot notation. For example:

val redColor = Color.RED
println(redColor.rgb)           // Output: 16711680
println(redColor.description()) // Output: Red color

Enums in Kotlin can be useful in various scenarios, such as representing days of the week, menu options, status codes, and more. They provide a type-safe and concise way to define a fixed set of values.

Kotlin - no_image

Enum in Kotlin

Further Reading:

credit goes to @swayangjit

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Written by Upendra Follow