CODEWITHSUNDEEP
kotlin
labed AbdelJalil
labed AbdelJalil

Reputation: 35

How to pass object as argument in Kotlin

I have these two objects A and B I want to use these objects interchangeably in the digit class like shown in this snippet code

internal object A {
    internal const val ZERO = "ZERO"
    internal const val ONE = "ONE"
}

internal object B {
    internal const val ZERO = "ZERO"
    internal const val ONE = "UN"
}


class Digit(Lang: String) {
    private var X: Any? = null

    init {
        when (Lang) {
            "eng" -> X = A
            "fr" -> X = B
        }
    }

    fun spell() {
        println(X.ZERO)
    }
}

I want inside the Digit class to use both objects, not at the same time, only when I want the English language the Digit class use object A and when I want french language the Digit class use the object B.

I should use reflection? or is there a better design?

Upvotes: 1

Views: 3878

Answers (2)

lukas.j
lukas.j

Reputation: 7163

data class Translation(val ZERO: String, val ONE: String)

val a = Translation(ZERO = "ZERO", ONE = "ONE")
val b = Translation(ZERO = "ZERO", ONE = "UN")

class Digit(Lang: Translation) {

  private val x = Lang

  fun spell() {
    println(x.ONE)
  }

}

Digit(a).spell()
Digit(b).spell()

Upvotes: 0

gidds
gidds

Reputation: 18557

The simplest answer is to have your objects all implement the same interface, e.g.:

interface Language {
    val ZERO: String
    val ONE: String
}

internal object A: Language {
    override val ZERO = "ZERO"
    override val ONE = "ONE"
}
// …

You can then set a Language reference to any object implementing that interface.

A related (and more concise) approach might be to use an enum:

enum class Language(val ZERO: String, val ONE: String) {
    A("ZERO", "ONE"), B("ZERO", "UN")
}

You can then refer to the objects as Language.A &c.

But in practice, none of these approaches scale well. You're likely to end up with a good number of language strings, and probably quite a few languages to support, and those methods will get long-winded. And hard-coding all the strings will make it much more awkward to manage.

So it's more usual to store all the language strings in resource files and load them in at runtime. You could do that manually, e.g. storing the strings in a map — but many platforms and frameworks support standard ways to select the right language, load the strings, and use them. There are many existing questions about this.

Upvotes: 6

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