I hope to construct MutableList a based List b, how can I do in Kotlin?
BTW, Code A is wrong
var a:MutableList<MSetting>
var b:List<MSetting>
Code A
var a=mutableListOf(b)
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3 Answers
Kotlin has a few versions of the toMutableList() extension function that should cover you. Check out the documentation here.
Basically, on any Collection, Interable, typed Array or generic Array, you can call .toMutableList() and it will creat a new MutableList (backed by ArrayList).
So in your code, you can do this (I'm showing types, you can leave them off):
var b: List<MSetting> = listOf(...)
var a: MutableList<MSetting> = b.toMutableList()
Comments
It is a generic and needs type information e.g.
var a = mutableListOf<Int>()
I tested at https://try.kotlinlang.org/#/
EDIT: I didn't read closely enough, what you want should be a toMutableList method.
var b = listOf(2, 3);
var a = b.toMutableList()
Comments
it's very easy:
val listB = listA?.toMutableList() ?: mutableListOf() // list B = A if (A != null), other wise, B = new empty list
