jsonlistkotlinjson-deserializationlistof

Convert volley string response (List<List<Int>>) to Kotlin list

Im stuck at what probably has a simple solution.

I have a string representation of a list, like this:

"[[1, 2, 3], [4, 5, 6]]"

In other words, a list containing 2 lists of 3 integers

How to convert the string to a list object of List<List> in Kotlin?

Solution

  • You can use kotlinx.serialization to deserialize JSON!

    As a standalone Kotlin script:

    @file:DependsOn("org.jetbrains.kotlinx:kotlinx-serialization-json:1.2.0")

import kotlinx.serialization.decodeFromString
import kotlinx.serialization.json.Json

val s = "[[1, 2, 3], [4, 5, 6]]"
val j = Json.decodeFromString<List<List<Int>>>(s)

println(j)         // [[1, 2, 3], [4, 5, 6]]
println(j[0][0])   // 1

    In an Android app's build.gradle you would need these lines instead of @file:DependsOn:

    dependencies {
    implementation 'org.jetbrains.kotlinx:kotlinx-serialization-json:1.2.0'
}

apply plugin: 'kotlinx-serialization'