Android Academy · Lesson

Lists and Mutable Lists

Store ordered data.

What Is a List?

A list is an ordered collection of items. Each item has a position, called an index, starting at 0.

In Kotlin, lists come in two flavors: read-only lists you cannot change, and mutable lists you can add to or remove from.

Lists are everywhere in Android apps: a feed of posts, a row of buttons, search results.

Use listOf() to create a read-only list. Once created, you cannot add or remove items.

This is the safest default. If your data never changes, prefer a read-only list.

fun main() {
    val fruits = listOf("apple", "banana", "cherry")
    println(fruits)
    println("Size: ${fruits.size}")
}