Kotlin: Return can be lifted out of ‘when’

You’re using when like a simple Java switch statement, which is okay but not very idiomatic and can be improved. You can refactor your code in two steps:

1. Kotlin’s when can be used as an expression, it returns a value if you wish:

    override fun getItemViewType(position: Int): Int {
        return when (position) {
            0 -> TITLE.type
            1 -> SUBTITLE.type
            2 -> ITEM.type
            else -> -1
         }
    }
   

2. The function body, now consisting of a single statement, can be changed into an expression body:

    override fun getItemViewType(position: Int) = when (position) {
         0 -> TITLE.type
         1 -> SUBTITLE.type
         2 -> ITEM.type
         else -> -1
    }