More idiomatic kotlin

when can return a value

app/src/main/java/chat/rocket/android/chatroom/ui/ChatRoomActivity.kt

@@ -13,6 +13,7 @@ import chat.rocket.android.server.infraestructure.ConnectionManagerFactory
 import chat.rocket.android.util.extensions.addFragment
 import chat.rocket.android.util.extensions.textContent
 import chat.rocket.common.model.RoomType
+import chat.rocket.common.model.roomTypeOf
 import dagger.android.AndroidInjection
 import dagger.android.AndroidInjector
 import dagger.android.DispatchingAndroidInjector
@@ -87,17 +88,18 @@ class ChatRoomActivity : AppCompatActivity(), HasSupportFragmentInjector {
         supportActionBar?.setDisplayShowTitleEnabled(false)
         text_room_name.textContent = chatRoomName
 
-        var drawable: Drawable? = null
-        when (chatRoomType) {
-            RoomType.CHANNEL.toString() -> {
-                drawable = DrawableHelper.getDrawableFromId(R.drawable.ic_room_channel, this)
+        val roomType = roomTypeOf(chatRoomType)
+        val drawable = when (roomType) {
+            is RoomType.Channel -> {
+                DrawableHelper.getDrawableFromId(R.drawable.ic_room_channel, this)
             }
-            RoomType.PRIVATE_GROUP.toString() -> {
-                drawable = DrawableHelper.getDrawableFromId(R.drawable.ic_room_lock, this)
+            is RoomType.PrivateGroup -> {
+                DrawableHelper.getDrawableFromId(R.drawable.ic_room_lock, this)
             }
-            RoomType.DIRECT_MESSAGE.toString() -> {
-                drawable = DrawableHelper.getDrawableFromId(R.drawable.ic_room_dm, this)
+            is RoomType.DirectMessage -> {
+                DrawableHelper.getDrawableFromId(R.drawable.ic_room_dm, this)
             }
+            else -> null
         }
 
         drawable?.let {

app/src/main/java/chat/rocket/android/chatrooms/ui/ChatRoomsAdapter.kt

@@ -76,27 +76,27 @@ class ChatRoomsAdapter(private val context: Context,
         private fun bindName(chatRoom: ChatRoom, textView: TextView) {
             textView.textContent = chatRoom.name
 
-            var drawable: Drawable? = null
-            when (chatRoom.type) {
+            var drawable = when (chatRoom.type) {
                 is RoomType.Channel -> {
-                    drawable = DrawableHelper.getDrawableFromId(R.drawable.ic_room_channel, context)
+                    DrawableHelper.getDrawableFromId(R.drawable.ic_room_channel, context)
                 }
                 is RoomType.PrivateGroup -> {
-                    drawable = DrawableHelper.getDrawableFromId(R.drawable.ic_room_lock, context)
+                    DrawableHelper.getDrawableFromId(R.drawable.ic_room_lock, context)
                 }
                 is RoomType.DirectMessage -> {
-                    drawable = DrawableHelper.getDrawableFromId(R.drawable.ic_room_dm, context)
+                    DrawableHelper.getDrawableFromId(R.drawable.ic_room_dm, context)
                 }
+                else -> null
             }
 
             drawable?.let {
                 val wrappedDrawable = DrawableHelper.wrapDrawable(it)
                 val mutableDrawable = wrappedDrawable.mutate()
-                DrawableHelper.tintDrawable(mutableDrawable, context,
-                        when (chatRoom.alert || chatRoom.unread > 0) {
+                val color = when (chatRoom.alert || chatRoom.unread > 0) {
                     true -> R.color.colorPrimaryText
                     false -> R.color.colorSecondaryText
-                        })
+                }
+                DrawableHelper.tintDrawable(mutableDrawable, context, color)
                 DrawableHelper.compoundDrawable(textView, mutableDrawable)
             }
         }