AOrobator

val song: Song = ...
val playlist: Playlist = ...

playlistRepository.addSongToPlaylist(song.typedId, playlist.typedId)

AOrobator

data class SongId(id: Long)
val Song.typedId: SongId = SongId(this.id)

data class PlaylistId(id: Long)
val Playlist.typedId: PlaylistId = PlaylistId(this.id)

AOrobator

// Compiler doesn’t like this. Red squigglies everywhere.
playlistRepository.addSongToPlaylist(songId = PlaylistId(420L), playlistId = SongId(9001L))

AOrobator

interface PlaylistRepository: Repository {
  fun addSongToPlaylist(songId: SongId, playlistId: PlaylistId)
}

AOrobator

data class SongId(id: Long)
data class PlaylistId(id: Long)

AOrobator

val playlist: Playlist = ...
val song: Song = ...

// This is a bug, but the compiler allows it!
playlistRepository.addSongToPlaylist(songId = playlist.id, playlistId = song.id)

AOrobator

interface PlaylistRepository: Repository {
  fun addSongToPlaylist(songId: Long, playlistId: Long)
}

AOrobator

@TargetApi(N_MR1)
override fun onOptionsItemSelected(item: MenuItem): Boolean {
  when (item.itemId) {
    R.id.enable_shortcut -> shortcutAction {
      it.enableShortcuts(listOf(constellation.name))
      alertUser(R.string.shortcut_enabled)
    }
    R.id.disable_shortcut -> shortcutAction {
      it.disableShortcuts(listOf(constellation.name))
      alertUser(R.string.shortcut_disabled)

AOrobator

/**
 * Sets the new Shortcut List by providing the three most visited
 * constellations
 * */
@TargetApi(N_MR1)
fun updateShortcuts(shortcutManager: ShortcutManager) {
  shortcutManager.dynamicShortcuts =
      Constellation
          .values()
          .sortedWith(compareBy { -getConstellationVisitedCount(it) })

AOrobator

inline fun shortcutAction(action: (ShortcutManager) -> Unit): Unit {
  if (SDK_INT >= N_MR1) {
    val shortcutManager = APP_CONTEXT.getSystemService(ShortcutManager::class.java)
    action(shortcutManager)
  }
}