Android Bundle enum support using kotlin extension methods

BundleEnumExtension.kt

import android.os.Bundle

// Dunno if there's a better way to extend both bundle and intents, but 
// you probably can extend intents in the same way

fun Bundle.putEnum(key:String, enum: Enum<*>){
    putString(key, enum.name)
}

inline fun <reified T: Enum<T>> Bundle.getEnum(key:String): T {
    return enumValueOf(getString(key))
}

Example.kt

enum class KotlinEnum {
  KOTLIN_IS_LOVE
}


class MyClass: Fragment() {
  companion object {
      private const val ENUM_KEY = "ENUM_KEY"
  }

  //... some fragment declaration code
  fun newInstance(ktEnum: KotlinEnum) {
        val args = Bundle()
        args.putEnum(ENUM_KEY, ktEnum)
    
        // Both way works
        val cEnum = args.getEnum(ENUM_KEY) as KotlinEnum
        val dEnum = args.getEnum<KotlinEnum>(ENUM_KEY)
  }
}

Just a quick quip, but maybe this instead...?

inline fun <reified T: Enum<T>> Bundle.getEnum(key: String, default: T): T {
    val found = getString(key)
    return if (found == null) { default } else enumValueOf(found)
}

Then you if you can have e.g.:

savedInstanceState.also {
    gameOver = it?.getEnum("gameOver", GameState.Running) ?: GameState.Running
}

...and the IDE doesn't scream it's lungs out :-)

In case you want to use null instead of default you can also create an extension like this:

inline fun <reified T: Enum<T>> Bundle.getEnum(key:String): T? {
    return getString(key)?.let { enumValueOf<T>(it) }
}