Start to display user groups

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;
+      });
+    }
+  }
+}