add RoomFragment.

app/src/main/java/chat/rocket/android/activity/MainActivity.java

@@ -2,11 +2,13 @@ package chat.rocket.android.activity;
 
 import android.os.Bundle;
 import android.support.annotation.Nullable;
+import android.support.v4.widget.SlidingPaneLayout;
 import android.widget.CompoundButton;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 import chat.rocket.android.R;
 import chat.rocket.android.fragment.chatroom.HomeFragment;
+import chat.rocket.android.fragment.chatroom.RoomFragment;
 import chat.rocket.android.helper.Avatar;
 import chat.rocket.android.layouthelper.chatroom.RoomListManager;
 import chat.rocket.android.model.Room;
@@ -44,11 +46,23 @@ public class MainActivity extends AbstractAuthedActivity {
     roomListManager = new RoomListManager(
         (LinearLayout) findViewById(R.id.channels_container),
         (LinearLayout) findViewById(R.id.direct_messages_container));
+    roomListManager.setOnItemClickListener(view -> {
+      showRoomFragment(view.getRoomId());
+      closeSidebarIfNeeded();
+    });
 
     ImageView myAvatar = (ImageView) findViewById(R.id.img_my_avatar);
     new Avatar("demo.rocket.chat", "John Doe").into(myAvatar);
   }
 
+  private void closeSidebarIfNeeded() {
+    // REMARK: Tablet UI doesn't have SlidingPane!
+    SlidingPaneLayout pane = (SlidingPaneLayout) findViewById(R.id.sliding_pane);
+    if (pane != null) {
+      pane.closePane();
+    }
+  }
+
   private void setupUserActionToggle() {
     final CompoundButton toggleUserAction =
         ((CompoundButton) findViewById(R.id.toggle_user_action));
@@ -71,6 +85,10 @@ public class MainActivity extends AbstractAuthedActivity {
     }
   };
 
+  private void showRoomFragment(String roomId) {
+    showFragment(RoomFragment.create(roomId));
+  }
+
   @Override protected void onResume() {
     super.onResume();
     roomsObserver.sub();

app/src/main/java/chat/rocket/android/fragment/chatroom/HomeFragment.java

@@ -3,6 +3,9 @@ package chat.rocket.android.fragment.chatroom;
 import chat.rocket.android.R;
 
 public class HomeFragment extends AbstractChatRoomFragment {
+  public HomeFragment() {
+  }
+
   @Override protected int getLayout() {
     return R.layout.fragment_home;
   }
@@ -10,4 +13,9 @@ public class HomeFragment extends AbstractChatRoomFragment {
   @Override protected void onSetupView() {
     activityToolbar.setTitle("Rocket.Chat - Home");
   }
+
+  @Override public void onResume() {
+    super.onResume();
+    activityToolbar.setTitle("Rocket.Chat - Home");
+  }
 }

app/src/main/java/chat/rocket/android/fragment/chatroom/RoomFragment.java

+package chat.rocket.android.fragment.chatroom;
+
+import android.os.Bundle;
+import android.support.annotation.Nullable;
+import chat.rocket.android.R;
+import chat.rocket.android.model.Room;
+import io.realm.Realm;
+import io.realm.RealmQuery;
+import jp.co.crowdworks.realm_java_helpers.RealmObjectObserver;
+
+/**
+ */
+public class RoomFragment extends AbstractChatRoomFragment {
+
+  private String roomId;
+
+  public static RoomFragment create(String roomId) {
+    Bundle args = new Bundle();
+    args.putString("roomId", roomId);
+    RoomFragment fragment = new RoomFragment();
+    fragment.setArguments(args);
+    return fragment;
+  }
+
+  public RoomFragment() {
+  }
+
+  @Override public void onCreate(@Nullable Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+
+    Bundle args = getArguments();
+    roomId = args.getString("roomId");
+  }
+
+  @Override protected int getLayout() {
+    return R.layout.fragment_room;
+  }
+
+  @Override protected void onSetupView() {
+
+  }
+
+  private RealmObjectObserver<Room> roomObserver = new RealmObjectObserver<Room>() {
+    @Override protected RealmQuery<Room> query(Realm realm) {
+      return realm.where(Room.class).equalTo("_id", roomId);
+    }
+
+    @Override protected void onChange(Room room) {
+      onRenderRoom(room);
+    }
+  };
+
+  private void onRenderRoom(Room room) {
+    activityToolbar.setTitle(room.getName());
+  }
+
+  @Override public void onResume() {
+    super.onResume();
+    roomObserver.sub();
+  }
+
+  @Override public void onPause() {
+    roomObserver.unsub();
+    super.onPause();
+  }
+}

app/src/main/java/chat/rocket/android/layouthelper/chatroom/RoomListManager.java

 package chat.rocket.android.layouthelper.chatroom;
 
+import android.view.View;
 import android.view.ViewGroup;
 import chat.rocket.android.helper.TextUtils;
 import chat.rocket.android.model.Room;
@@ -13,6 +14,15 @@ public class RoomListManager {
   private ViewGroup channelsContainer;
   private ViewGroup dmContainer;
 
+  /**
+   * Callback interface for List item clicked.
+   */
+  public interface OnItemClickListener {
+    void onItemClick(RoomListItemView roomListItemView);
+  }
+
+  private OnItemClickListener mListener;
+
   /**
    * constructor with two ViewGroups.
    */
@@ -43,13 +53,20 @@ public class RoomListManager {
     }
   }
 
-  private static void insertOrUpdateItem(ViewGroup parent, Room room) {
+  /**
+   * set callback on List item clicked.
+   */
+  public void setOnItemClickListener(OnItemClickListener listener) {
+    mListener = listener;
+  }
+
+  private void insertOrUpdateItem(ViewGroup parent, Room room) {
     final String roomName = room.getName();
 
     int index;
     for (index = 0; index < parent.getChildCount(); index++) {
       RoomListItemView roomListItemView = (RoomListItemView) parent.getChildAt(index);
-      final String targetRoomName = roomListItemView.getName();
+      final String targetRoomName = roomListItemView.getRoomName();
       if (roomName.equals(targetRoomName)) {
         updateRoomItemView(roomListItemView, room);
         return;
@@ -68,16 +85,28 @@ public class RoomListManager {
     }
   }
 
-  private static void updateRoomItemView(RoomListItemView roomListItemView, Room room) {
+  private void updateRoomItemView(RoomListItemView roomListItemView, Room room) {
     roomListItemView
-        .setRoom(room.getT(), room.getName())
+        .setRoomId(room.get_id())
+        .setRoomName(room.getName())
+        .setRoomType(room.getT())
         .setAlertCount(0); // TODO not implemented yet.
+
+    roomListItemView.setOnClickListener(this::onItemClick);
+  }
+
+  private void onItemClick(View view) {
+    if (view instanceof RoomListItemView) {
+      if (mListener != null) {
+        mListener.onItemClick((RoomListItemView) view);
+      }
+    }
   }
 
   private static void removeItemIfExists(ViewGroup parent, String roomName) {
     for (int i = 0; i < parent.getChildCount(); i++) {
       RoomListItemView roomListItemView = (RoomListItemView) parent.getChildAt(i);
-      if (roomName.equals(roomListItemView.getName())) {
+      if (roomName.equals(roomListItemView.getRoomName())) {
         parent.removeViewAt(i);
         break;
       }

app/src/main/res/layout/activity_main.xml

 <?xml version="1.0" encoding="utf-8"?>
 <android.support.v4.widget.SlidingPaneLayout
+    android:id="@+id/sliding_pane"
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
@@ -33,6 +34,7 @@
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:background="@color/white"
+        android:clickable="true"
         app:layout_behavior="@string/appbar_scrolling_view_behavior"
         ></FrameLayout>
 

app/src/main/res/layout/fragment_room.xml

+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+  <android.support.v7.widget.RecyclerView
+      android:id="@+id/recyclerview"
+      android:layout_width="match_parent"
+      android:layout_height="match_parent"
+      />
+
+  <android.support.design.widget.FloatingActionButton
+      android:id="@+id/btn_compose"
+      android:layout_width="wrap_content"
+      android:layout_height="wrap_content"
+      android:layout_gravity="end|bottom"
+      android:layout_margin="@dimen/margin_16"
+      />
+</FrameLayout>
\ No newline at end of file

rocket-chat-android-widgets/src/main/java/chat/rocket/android/widget/internal/RoomListItemView.java

@@ -2,6 +2,7 @@ package chat.rocket.android.widget.internal;
 
 import android.annotation.TargetApi;
 import android.content.Context;
+import android.content.res.TypedArray;
 import android.os.Build;
 import android.util.AttributeSet;
 import android.view.View;
@@ -14,7 +15,8 @@ import java.util.HashMap;
  * Room list-item view used in sidebar.
  */
 public class RoomListItemView extends LinearLayout {
-  private String name;
+  private String roomId;
+  private String roomName;
 
   private static HashMap<String, Integer> ICON_TABLE = new HashMap<String, Integer>(){
     {
@@ -47,19 +49,31 @@ public class RoomListItemView extends LinearLayout {
 
   private void initialize(Context context) {
     setOrientation(HORIZONTAL);
+
+    TypedArray array2 = context.getTheme().obtainStyledAttributes(new int[]{
+        R.attr.selectableItemBackground
+    });
+    setBackground(array2.getDrawable(0));
+    array2.recycle();
+
     View.inflate(context, R.layout.room_list_item, this);
   }
 
-  public RoomListItemView setRoom(String type, String name) {
+  public String getRoomId() {
+    return roomId;
+  }
+
+  public RoomListItemView setRoomId(String roomId) {
+    this.roomId = roomId;
+    return this;
+  }
+
+  public RoomListItemView setRoomType(String type) {
     if (ICON_TABLE.containsKey(type)) {
       TextView icon = (TextView) findViewById(R.id.icon);
       icon.setText(ICON_TABLE.get(type));
     }
 
-    TextView text = (TextView) findViewById(R.id.text);
-    text.setText(name);
-    this.name = name;
-
     return this;
   }
 
@@ -76,7 +90,15 @@ public class RoomListItemView extends LinearLayout {
     return this;
   }
 
-  public String getName() {
-    return name;
+  public String getRoomName() {
+    return roomName;
+  }
+
+  public RoomListItemView setRoomName(String roomName) {
+    this.roomName = roomName;
+    TextView text = (TextView) findViewById(R.id.text);
+    text.setText(roomName);
+
+    return this;
   }
 }

rocket-chat-android-widgets/src/main/res/layout/room_list_item.xml

@@ -5,7 +5,8 @@
   <FrameLayout
       android:layout_width="32dp"
       android:layout_height="?attr/listPreferredItemHeightSmall"
-      android:layout_marginEnd="16dp">
+      android:layout_marginEnd="16dp"
+      >
     <chat.rocket.android.widget.FontAwesomeTextView
         android:id="@+id/icon"
         android:layout_width="wrap_content"