Sort chat list data by lastMessageDateTime.

app/src/main/java/chat/rocket/android/app/chatlist/ChatListFragment.kt

@@ -24,21 +24,21 @@ class ChatListFragment : Fragment() {
     }
 
     // This is just a sample showing 6 chat rooms (aka user subscription). We need to get it rid in a real word. REMARK: remove this comment and this method.
-    private fun createDumpData(): MutableList<Chat> {
-        val dumpChat1 = Chat("https://open.rocket.chat/avatar/filipe.brito",
-                "Filipe Brito",
-                "d",
-                "online",
-                "Type something...Type something...Type something",
-                LocalDateTime.of(2017, 11, 22,1, 3),
-                150)
-        val dumpChat2 = Chat("https://open.rocket.chat/avatar/leonardo.aramaki",
+    private fun createDumpData(): List<Chat> {
+        val dumpChat1 = Chat("https://open.rocket.chat/avatar/leonardo.aramaki",
                 "Leonardo Aramaki",
                 "d",
                 "busy",
                 "Type something",
                 LocalDateTime.of(2017, 11, 21,1, 3),
                 1)
+        val dumpChat2 = Chat("https://open.rocket.chat/avatar/filipe.brito",
+                "Filipe Brito",
+                "d",
+                "online",
+                "Type something...Type something...Type something",
+                LocalDateTime.of(2017, 11, 22,1, 3),
+                150)
         val dumpChat3 = Chat("https://open.rocket.chat/avatar/lucio.maciel",
                 "Lucio Maciel",
                 "d",
@@ -53,27 +53,29 @@ class ChatListFragment : Fragment() {
                 "@aaron.ogle @rafael.kellermann same problem over here. Although all the servers show up on the selection.",
                 LocalDateTime.of(2017, 11, 15,1, 3),
                 0)
-        val dumpChat5 = Chat("https://open.rocket.chat/avatar/matheus.cardoso",
-                "androidnativeapp",
-                "c",
-                null,
-                "Yes @sttyru, but you'll need to implement from the ground up following the docs at docs.rocket.chat where you can see the REST (HTTP) and Real-Time (WebSockets) calls.",
-                LocalDateTime.of(2017, 11, 14,1, 3),
-                0)
-        val dumpChat6 = Chat("https://open.rocket.chat/avatar/hetal",
+        val dumpChat5 = Chat("https://open.rocket.chat/avatar/hetal",
                 "general",
                 "c",
                 null,
                 "Has joined the channel.",
                 LocalDateTime.of(2017, 11, 13,1, 3),
                 0)
-        return arrayListOf(dumpChat1, dumpChat2, dumpChat3, dumpChat4, dumpChat5, dumpChat6)
+        val dumpChat6 = Chat("https://open.rocket.chat/avatar/matheus.cardoso",
+                "androidnativeapp",
+                "c",
+                null,
+                "Yes @sttyru, but you'll need to implement from the ground up following the docs at docs.rocket.chat where you can see the REST (HTTP) and Real-Time (WebSockets) calls.",
+                LocalDateTime.of(2017, 11, 14,1, 3),
+                0)
+
+        // creates a list of chat sorted by lastMessageDateTime attribute.
+        return listOf(dumpChat1, dumpChat2, dumpChat3, dumpChat4, dumpChat5, dumpChat6).sortedByDescending { chat -> chat.lastMessageDateTime }
     }
 
     // REMARK: The presenter should call this method. The presenter also need to sort the chat list by latest message (compared by its date).
-    private fun showChatList(dataSet: MutableList<Chat>) {
+    private fun showChatList(dataSet: List<Chat>) {
         val context = activity.applicationContext
-        recycler_view.adapter = ChatListAdapter(dataSet, context)
+        recycler_view.adapter = ChatListAdapter(dataSet.toMutableList(), context)
         recycler_view.layoutManager = LinearLayoutManager(context, LinearLayoutManager.VERTICAL, false)
         recycler_view.addItemDecoration(DividerItemDecoration(activity, DividerItemDecoration.VERTICAL))
     }