Start to display user groups

lib/ui/routes/home_route.dart

@@ -2,6 +2,7 @@ import 'package:comunic/helpers/account_helper.dart';
 import 'package:comunic/ui/routes/app_settings_route.dart';
 import 'package:comunic/ui/screens/conversations_list_screen.dart';
 import 'package:comunic/ui/screens/friends_list_screen.dart';
+import 'package:comunic/ui/screens/groups_list_screen.dart';
 import 'package:comunic/ui/screens/newest_posts.dart';
 import 'package:comunic/ui/screens/notifications_screen.dart';
 import 'package:comunic/ui/widgets/navbar_widget.dart';
@@ -89,6 +90,9 @@ class _HomeRouteState extends State<HomeRoute> {
       case BarCallbackActions.OPEN_FRIENDS:
         return FriendsListScreen();
 
+      case BarCallbackActions.OPEN_GROUPS:
+        return GroupsListScreen();
+
       default:
         throw "Invalid tab : " + _currTab.toString();
     }

lib/ui/screens/groups_list_screen.dart

@@ -0,0 +1,84 @@
+import 'package:comunic/helpers/groups_helper.dart';
+import 'package:comunic/lists/groups_list.dart';
+import 'package:comunic/ui/widgets/group_icon_widget.dart';
+import 'package:comunic/ui/widgets/safe_state.dart';
+import 'package:comunic/utils/intl_utils.dart';
+import 'package:comunic/utils/ui_utils.dart';
+import 'package:flutter/material.dart';
+
+/// Groups list screen
+///
+/// @author Pierre Hubert
+
+class GroupsListScreen extends StatefulWidget {
+  @override
+  _GroupsListScreenState createState() => _GroupsListScreenState();
+}
+
+class _GroupsListScreenState extends SafeState<GroupsListScreen> {
+  /// The list of groups
+  GroupsList _groups;
+
+  bool _error = false;
+
+  @override
+  void initState() {
+    super.initState();
+
+    this._refreshList();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      children: <Widget>[
+        // Error
+        buildErrorCard(
+          tr("Could not load the list of groups!"),
+          hide: !_error,
+          actions: [
+            MaterialButton(
+              child: Text(tr("Try again".toUpperCase())),
+              onPressed: () => _refreshList(),
+            ),
+          ],
+        ),
+
+        // List of groups
+        Expanded(
+            child: RefreshIndicator(
+          onRefresh: () => this._refreshList(),
+          child: _groups == null
+              ? Container()
+              : ListView(
+                  children: _groups.values
+                      .map((g) => ListTile(
+                            leading: GroupIcon(group: g),
+                            title: Text(g.displayName),
+                          ))
+                      .toList(),
+                ),
+        ))
+      ],
+    );
+  }
+
+  /// Refresh the list of groups
+  Future<void> _refreshList() async {
+    try {
+      final list = await GroupsHelper().getListUser();
+      final groups = await GroupsHelper().getListOrThrow(list, force: true);
+
+      setState(() {
+        _groups = groups;
+        _error = false;
+      });
+    } catch (e) {
+      print(e);
+
+      setState(() {
+        _error = true;
+      });
+    }
+  }
+}

lib/ui/widgets/group_icon_widget.dart

@@ -0,0 +1,50 @@
+import 'package:cached_network_image/cached_network_image.dart';
+import 'package:comunic/models/group.dart';
+import 'package:flutter/material.dart';
+
+/// Custom group icon
+///
+/// @author Pierre Hubert
+class GroupIcon extends StatelessWidget {
+  final Group group;
+  final double width;
+
+  const GroupIcon({
+    Key key,
+    @required this.group,
+    this.width = 50,
+  })  : assert(group != null),
+        assert(width != null),
+        super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Material(
+      child: CachedNetworkImage(
+        imageUrl: group.iconURL,
+        width: width,
+        height: width,
+        placeholder: (c, s) => Container(
+          color: Colors.grey,
+          width: width,
+          height: width,
+          child: Padding(
+            padding: const EdgeInsets.all(8.0),
+            child: CircularProgressIndicator(
+              strokeWidth: 4.0,
+            ),
+          ),
+        ),
+        errorWidget: (c, s, o) => Container(
+          color: Colors.red,
+          width: width,
+          height: width,
+          child: Icon(
+            Icons.error,
+            color: Colors.white,
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/ui/widgets/navbar_widget.dart

@@ -15,6 +15,7 @@ enum BarCallbackActions {
   OPEN_NEWEST_POSTS,
   OPEN_FRIENDS,
   OPEN_MY_PAGE,
+  OPEN_GROUPS,
   OPEN_APP_SETTINGS,
   NONE,
   ACTION_LOGOUT
@@ -81,6 +82,7 @@ final _menuItems = <_MenuItem>[
 final _menuActionsItem = <_ActionMenuItem>[
   _ActionMenuItem(
       label: tr("My Page"), action: BarCallbackActions.OPEN_MY_PAGE),
+  _ActionMenuItem(label: tr("Groups"), action: BarCallbackActions.OPEN_GROUPS),
   _ActionMenuItem(
       label: tr("App settings"), action: BarCallbackActions.OPEN_APP_SETTINGS),
   _ActionMenuItem(