refactor: error loading wrapper

lib/scaffolds/refresh_stateful.dart

@@ -1,8 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:git_touch/scaffolds/utils.dart';
-import '../widgets/loading.dart';
-import '../widgets/error_reload.dart';
 
 class RefreshStatefulScaffold<T> extends StatefulWidget {
   final Widget title;
@@ -58,21 +56,19 @@ class _RefreshStatefulScaffoldState<T>
     return widget.trailingBuilder(_payload);
   }
 
-  Widget get _body {
-    if (_error.isNotEmpty) {
-      return ErrorReload(text: _error, onTap: _refresh);
-    } else if (_payload == null) {
-      return Loading(more: false);
-    } else {
-      return widget.bodyBuilder(_payload);
-    }
-  }
-
   @override
   Widget build(BuildContext context) {
     return CommonScaffold(
       title: widget.title,
-      body: RefreshWrapper(onRefresh: _refresh, body: _body),
+      body: RefreshWrapper(
+        onRefresh: _refresh,
+        body: ErrorLoadingWrapper(
+          bodyBuilder: () => widget.bodyBuilder(_payload),
+          error: _error,
+          loading: _payload == null,
+          reload: _refresh,
+        ),
+      ),
       trailing: _trailing,
     );
   }

lib/scaffolds/tab.dart

@@ -4,30 +4,23 @@ import 'package:git_touch/models/theme.dart';
 import 'package:git_touch/scaffolds/utils.dart';
 import 'package:provider/provider.dart';
 
-class CommonTabPayload {
-  final List<String> tabs;
-  final int activeTab;
-  final Function(int active) onTabSwitch;
-  CommonTabPayload({
-    @required this.tabs,
-    @required this.activeTab,
-    @required this.onTabSwitch,
-  });
-}
-
 class TabScaffold extends StatelessWidget {
   final Widget title;
   final Widget body;
   final Widget trailing;
   final void Function() onRefresh;
-  final CommonTabPayload tabPayload;
+  final List<String> tabs;
+  final int activeTab;
+  final Function(int index) onTabSwitch;
 
   TabScaffold({
     @required this.title,
     @required this.body,
     this.trailing,
     @required this.onRefresh,
-    @required this.tabPayload,
+    @required this.tabs,
+    @required this.activeTab,
+    @required this.onTabSwitch,
   });
 
   Widget _buildTitle(BuildContext context) {
@@ -36,9 +29,9 @@ class TabScaffold extends StatelessWidget {
         return DefaultTextStyle(
           style: TextStyle(fontSize: 16),
           child: CupertinoSegmentedControl(
-            groupValue: tabPayload.activeTab,
+            groupValue: activeTab,
-            onValueChanged: tabPayload.onTabSwitch,
+            onValueChanged: onTabSwitch,
-            children: tabPayload.tabs.asMap().map((key, text) => MapEntry(
+            children: tabs.asMap().map((key, text) => MapEntry(
                 key,
                 Padding(
                   padding: const EdgeInsets.symmetric(horizontal: 8),
@@ -58,10 +51,8 @@ class TabScaffold extends StatelessWidget {
       body: RefreshWrapper(body: body, onRefresh: onRefresh),
       trailing: trailing,
       bottom: TabBar(
-        onTap: tabPayload.onTabSwitch,
+        onTap: onTabSwitch,
-        tabs: tabPayload.tabs
+        tabs: tabs.map((text) => Tab(text: text.toUpperCase())).toList(),
-            .map((text) => Tab(text: text.toUpperCase()))
-            .toList(),
       ),
     );
 
@@ -70,7 +61,7 @@ class TabScaffold extends StatelessWidget {
         return scaffold;
       default:
         return DefaultTabController(
-          length: tabPayload.tabs.length,
+          length: tabs.length,
           child: scaffold,
         );
     }

lib/scaffolds/tab_stateful.dart

@@ -1,8 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:git_touch/scaffolds/tab.dart';
-import '../widgets/loading.dart';
+import 'package:git_touch/scaffolds/utils.dart';
-import '../widgets/error_reload.dart';
 
 class TabStatefulScaffold<T> extends StatefulWidget {
   final Widget title;
@@ -66,16 +65,6 @@ class _TabStatefulScaffoldState<T> extends State<TabStatefulScaffold<T>> {
     _refresh();
   }
 
-  Widget _buildBody() {
-    if (_error.isNotEmpty) {
-      return ErrorReload(text: _error, onTap: _refresh);
-    } else if (_payload == null) {
-      return Loading(more: false);
-    } else {
-      return widget.bodyBuilder(_payload, _activeTab);
-    }
-  }
-
   Future<void> _refresh() async {
     try {
       setState(() {
@@ -114,13 +103,16 @@ class _TabStatefulScaffoldState<T> extends State<TabStatefulScaffold<T>> {
     return TabScaffold(
       title: widget.title,
       trailing: _buildTrailing(),
-      tabPayload: CommonTabPayload(
+      tabs: widget.tabs,
-        tabs: widget.tabs,
+      activeTab: _activeTab,
-        activeTab: _activeTab,
+      onTabSwitch: _switch,
-        onTabSwitch: _switch,
-      ),
       onRefresh: _refresh,
-      body: _buildBody(),
+      body: ErrorLoadingWrapper(
+        bodyBuilder: () => widget.bodyBuilder(_payload, _activeTab),
+        error: _error,
+        loading: _payload == null,
+        reload: _refresh,
+      ),
     );
   }
 }

lib/scaffolds/utils.dart

@@ -1,6 +1,8 @@
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:git_touch/models/theme.dart';
+import 'package:git_touch/widgets/link.dart';
+import 'package:git_touch/widgets/loading.dart';
 import 'package:provider/provider.dart';
 
 class CommonScaffold extends StatelessWidget {
@@ -67,3 +69,63 @@ class RefreshWrapper extends StatelessWidget {
     }
   }
 }
+
+class ErrorLoadingWrapper extends StatelessWidget {
+  final String error;
+  final bool loading;
+  final void Function() reload;
+  final Widget Function() bodyBuilder;
+
+  ErrorLoadingWrapper({
+    @required this.error,
+    @required this.loading,
+    @required this.reload,
+    @required this.bodyBuilder,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    if (error.isNotEmpty) {
+      return Container(
+        padding: EdgeInsets.symmetric(vertical: 30, horizontal: 20),
+        child: Column(
+          children: <Widget>[
+            Text(
+              'Woops, something bad happened. Error message:',
+              style: TextStyle(fontSize: 16),
+            ),
+            Padding(padding: EdgeInsets.only(top: 10)),
+            Text(
+              error,
+              style: TextStyle(
+                fontSize: 14,
+                fontWeight: FontWeight.w300,
+                color: Colors.redAccent,
+              ),
+            ),
+            Padding(padding: EdgeInsets.only(top: 10)),
+            Link(
+              child: Text(
+                'Reload',
+                style: TextStyle(fontSize: 20, color: Colors.blueAccent),
+              ),
+              onTap: reload,
+              material: false,
+            ),
+          ],
+        ),
+      );
+    }
+
+    if (loading) {
+      return Loading();
+    }
+
+    return bodyBuilder();
+  }
+}
+
+Widget wrapBuilder(Widget Function() builder) {
+  if (builder == null) return null;
+  return builder();
+}