CODEWITHSUNDEEP
androidarrayssortingkotlin
GPH
GPH

Reputation: 1161

kotlin Android sortwith Array issue

I use the below sortwith method to sort my ArrayList, I suppose it will sort the order number from small number to big number. Such as 10,9,8,7,6....0. But the result is not what I expected.Please kindly help to solve this issue.

companyList.add(companyReg)
companyList.sortedWith(compareBy { it.order })

for (obj in companyList) {
    println("order number: "+obj.order)
}

Println result enter image description here

Upvotes: 3

Views: 4473

Answers (2)

Cililing
Cililing

Reputation: 4753

See this example:

fun main(args: Array<String>) {
    val xx = ArrayList<Int>()
    xx.addAll(listOf(8, 3, 1, 4))
    xx.sortedWith(compareBy { it })

    // prints 8, 3, 1, 4
    xx.forEach { println(it) }

    println()

    val sortedXx = xx.sortedWith(compareBy { it })
    // prints sorted collection
    sortedXx.forEach { println(it) }
}

In Kotlin, most collections are immutable. And collection.sortedWith(...) is an extension function which returns a sorted copy of your collection, but in fact you ignore this result.

Of course, you can use other methods modifying collections (like .sort()), or Collections.sort(collection, comparator). This way of sorting doesn't require assigning new collection (because there is no new collection, only current is modified).

Upvotes: 9

V&#245; Quang H&#242;a
V&#245; Quang H&#242;a

Reputation: 3025

Try this

companyList = companyList.sortedWith(compareBy { it.order })

You can check the document here https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/sorted-with.html

Upvotes: 1

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