Cannot make a generic item in Kotlin

问题

I want to make the following line of code generic:

val newItem: Item = documentChange.document.toObject<Item>(Item::class.java)

Works fine. However, when I try to make it generic:

val addedItem: T = documentChange.document.toObject<T>(T::class.java)

Android Studio is complaining:

Cannot use 'T' as reified type parameter. Use a class instead.

Screenshot

How can I make it generic?

回答1:

You need to make a function inline and add reified keyword to the generic parameter:

inline fun <reified T> someFun() {
    //...
    val addedItem: T = documentChange.document.toObject<T>(T::class.java)
}

来源：https://stackoverflow.com/questions/62637460/cannot-make-a-generic-item-in-kotlin