I have a mutable list which can have items of different data classes. For example, val items: List<ItemData>, and ItemData is a class of
sealed class ItemData {
data class itemOne(
val valueOne
) : ItemData()
data class itemTwo(
val valueTwo
) : ItemData()
data class itemThree(
val valueThree
) : ItemData()
}
Say I want to take the list and whenever item is of certain type, update some value there. My question is, how to make sure that item is exactly the type I need? I tried with item as ItemData.itemTwo but I get class cast exception, since in my list are items of other types, too.
@aswi We can achieve this by using when with is check, please refer to below code sample:
// ItemData class
sealed class ItemData {
data class ItemOne(
val valueOne: Int
) : ItemData()
data class ItemTwo(
val valueTwo: String
) : ItemData()
data class ItemThree(
val valueThree: Boolean
) : ItemData()
}
This is how the type check works:
@JvmStatic
fun main(args: Array<String>) {
val mixedList = listOf(
ItemData.ItemOne(1), ItemData.ItemTwo("One"), ItemData.ItemThree(true)
)
mixedList.forEach { itemData ->
when (itemData) {
is ItemData.ItemOne -> println("This is ItemOne")
is ItemData.ItemTwo -> println("This is ItemTwo")
is ItemData.ItemThree -> println("This is ItemThree")
}
}
}
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