Improve groups page performances

lib/ui/screens/authorized_group_page_screen.dart

@@ -10,7 +10,6 @@ import 'package:comunic/ui/widgets/group_membership_widget.dart';
 import 'package:comunic/ui/widgets/like_widget.dart';
 import 'package:comunic/ui/widgets/post_create_form_widget.dart';
 import 'package:comunic/ui/widgets/posts_list_widget.dart';
-import 'package:comunic/ui/widgets/scroll_watcher.dart';
 import 'package:comunic/utils/intl_utils.dart';
 import 'package:flutter/material.dart';
 
@@ -42,30 +41,13 @@ class AuthorizedGroupPageScreen extends StatefulWidget {
 class _AuthorizedGroupPageScreenState extends State<AuthorizedGroupPageScreen> {
   AdvancedGroupInfo get _group => widget.advancedGroupInfo;
 
-  // Allows load older posts when we reach the bottom of the page
   final _postsKey = GlobalKey<PostsListWidgetState>();
-  ScrollWatcher _postsController;
-
-  @override
-  void initState() {
-    _postsController = ScrollWatcher(
-        onReachBottom: () => _postsKey.currentState.reachedPostsBottom());
-    super.initState();
-  }
 
   @override
   Widget build(BuildContext context) {
     return RefreshIndicator(
       onRefresh: () => widget.needRefresh(),
-      child: ListView(
-        physics: AlwaysScrollableScrollPhysics(),
-        controller: _postsController,
-        children: <Widget>[
-          _buildGroupPageHeader(),
-          _buildPostCreationArea(),
-          _buildGroupPagePostsList()
-        ],
-      ),
+      child: _buildGroupPagePostsList(),
     );
   }
 
@@ -141,11 +123,14 @@ class _AuthorizedGroupPageScreenState extends State<AuthorizedGroupPageScreen> {
   Widget _buildGroupPagePostsList() {
     return PostsListWidget(
       key: _postsKey,
+      topWidgets: <Widget>[
+        _buildGroupPageHeader(),
+        _buildPostCreationArea(),
+      ],
       getPostsList: () => PostsHelper().getGroupPosts(_group.id),
       showPostsTarget: false,
       userNamesClickable: true,
       getOlder: (from) => PostsHelper().getGroupPosts(_group.id, from: from),
-      buildListView: false,
     );
   }