Kotlin - Array of object (no null)

Question

I'm coding in kotlin, and i have a problem with the Arrays

I would make a function that return an Array of Car (for example), but that array is build by data from file

Exemple :

fun buildAllCar(data:string) : Array<Car> {
    val array = arrayOfNulls<Location>(5) //In the real code, the size is retrieved by an other item

    for(i in array.indices){
        array[i] = buildACarByData(data); //Just so you could see a sample usage
    }

    return array.requireNoNulls()
}

Without the requireNoNulls() , the type of object returned is Array of Car? Use this method is the only way to get an Array of Car or there is a other way?

Thanks for your help

buildAllCar is having return type as Array of car and varible array is of type array of Location. Also please explain more about your problem — Kishan Maurya
– Kishan Maurya, Commented Feb 14, 2020 at 17:19
Does it need to be an Array? A List would seem to be more appropriate. (Arrays are needed for backward compatibility, but lists are more flexible and powerful and better for most things.) — gidds
– gidds, Commented Feb 14, 2020 at 21:33

pavi2410 · Accepted Answer · 2020-02-14 18:03:46Z

2

You can initialize an array in Kotlin using a mapper function like so

val array = Array(size, mapper function)

So to construct an Array of non-nullable Car

fun buildAllCar(data: String): Array<Car> = Array(5) { buildACarByData(data) }

answered Feb 14, 2020 at 18:03

pavi2410

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Pawan Soni · Accepted Answer · 2020-02-14 17:52:09Z

0

Change the code and modify return type of Array because when you apply return type, Kotlin check the nullablity so "?" define with safe call and return list if if the array list objects are null.

fun buildAllCar(data:string) : Array<Car?> {
    val array = arrayOfNulls<Location>(5) //In the real code, the size is retrieved by an other item

    for(i in array.indices){
        array[i] = buildACarByData(data); //Just so you could see a sample usage
    }

    return array
}

edited Feb 14, 2020 at 17:52

answered Feb 14, 2020 at 17:39

Pawan Soni

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