Kotlin enum class extension for Android (SharedPreference, Parcelable, Bundle, Intent)

Enum.kt

import android.content.SharedPreferences
import android.os.Bundle
import android.os.Parcel

inline fun <reified T : Enum<T>> Bundle.getEnum(key: String, default: T) =
        getInt(key).let { if (it >= 0) enumValues<T>()[it] else default }

fun <T : Enum<T>> Bundle.putEnum(key: String, value: T?) =
        putInt(key, value?.ordinal ?: -1)

inline fun <reified T : Enum<T>> SharedPreferences.getEnum(key: String, default: T) =
        this.getInt(key, -1).let { if (it >= 0) enumValues<T>()[it] else default }

fun <T : Enum<T>> SharedPreferences.Editor.putEnum(key: String, value: T?) : SharedPreferences.Editor =
        this.putInt(key, value?.ordinal ?: -1)

inline fun <reified T : Enum<T>> Parcel.readEnum() =
        readInt().let { if (it >= 0) enumValues<T>()[it] else null }

fun <T : Enum<T>> Parcel.writeEnum(value: T?) =
        writeInt(value?.ordinal ?: -1)

inline fun <reified T1 : Enum<T1>, T2 : Number> fromNumber(value: T2) : T1? =
        enumValues<T1>().firstOrNull { it.ordinal == value }

inline fun <reified T1 : Enum<T1>> fromInt(value: Int) : T1? = fromNumber<T1, Int>(value)

inline fun <reified T1 : Enum<T1>> fromLong(value: Long) : T1? = fromNumber<T1, Long>(value)

To use Kotlin enum classes within recycler adapters:

    private enum class ItemViewType {
        A,
        B
    }

    override fun getItemViewType(position: Int): Int {
        return when {
            isAOnPosition(position) -> ItemViewType.A.ordinal
            isBOnPosition(position) -> ItemViewType.B.ordinal
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, itemViewType: Int): RecyclerView.ViewHolder {
        return when (fromInt<ItemViewType>(itemViewType)) {
            ItemViewType.A -> ARecyclerViewHolder(inflater.inflate(R.layout.view_a_item, parent, false))
            ItemViewType.B -> BRecyclerViewHolder(inflater.inflate(R.layout.view_b_item, parent, false))
        }
    }