system generated tagGroups can only be inspected, not edited

lib/models/tag_group.dart

 import 'package:encrateia/models/tag.dart';
+import 'package:encrateia/utils/my_color.dart';
 import 'package:flutter/material.dart';
 import 'package:encrateia/model/model.dart';
 import 'package:encrateia/models/athlete.dart';
@@ -20,10 +21,11 @@ class TagGroup extends ChangeNotifier {
   TagGroup.by(
       {@required Athlete athlete,
       @required String name,
-      @required bool system}) {
+      @required bool system,
+      @required int color}) {
     db = DbTagGroup()
       ..athletesId = athlete.db.id
-      ..color = Colors.lightGreen.value
+      ..color = color
       ..system = system
       ..name = name;
   }
@@ -39,6 +41,7 @@ class TagGroup extends ChangeNotifier {
       name: "Auto Heart Rate Zones",
       athlete: athlete,
       system: true,
+      color: MyColor.grapeFruit.value,
     );
     await autoHeartRateZones.db.save();
 
@@ -46,6 +49,7 @@ class TagGroup extends ChangeNotifier {
       name: "Auto Power Zones",
       athlete: athlete,
       system: true,
+      color: MyColor.bitterSweet.value,
     );
     await autoPowerZonesTagGroup.db.save();
   }

lib/screens/show_tag_group_screen.dart

+import 'package:encrateia/utils/my_button.dart';
+import 'package:encrateia/utils/my_color.dart';
+import 'package:flutter/material.dart';
+import 'package:encrateia/models/tag_group.dart';
+import 'package:encrateia/models/tag.dart';
+import 'package:flutter_material_color_picker/flutter_material_color_picker.dart';
+
+class ShowTagGroupScreen extends StatefulWidget {
+  final TagGroup tagGroup;
+
+  const ShowTagGroupScreen({Key key, this.tagGroup}) : super(key: key);
+
+  @override
+  _AddTagGroupScreenState createState() => _AddTagGroupScreenState();
+}
+
+class _AddTagGroupScreenState extends State<ShowTagGroupScreen> {
+  List<Tag> tags = [];
+  int offset = 0;
+  int rows;
+
+  @override
+  void initState() {
+    getData();
+    super.initState();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        backgroundColor: MyColor.settings,
+        title: Text('Show Tag Group'),
+      ),
+      body: ListView(
+        padding: EdgeInsets.only(left: 20, right: 20),
+        children: <Widget>[
+          TextFormField(
+            decoration: InputDecoration(labelText: "Name"),
+            initialValue: widget.tagGroup.db.name,
+            readOnly: true,
+          ),
+          SizedBox(height: 20),
+          Row(children: [
+            Text("Color"),
+            Spacer(),
+            CircleAvatar(
+              backgroundColor: Color(widget.tagGroup.db.color),
+              radius: 20.0,
+            ),
+            Spacer(),
+          ]),
+          SizedBox(height: 20),
+          DataTable(
+            headingRowHeight: kMinInteractiveDimension * 0.80,
+            dataRowHeight: kMinInteractiveDimension * 0.75,
+            columnSpacing: 20,
+            horizontalMargin: 10,
+            columns: <DataColumn>[
+              DataColumn(label: Text("Tag")),
+              DataColumn(label: Text("Color")),
+            ],
+            rows: tags.map((Tag tag) {
+              return DataRow(
+                key: Key(tag.db.id.toString()),
+                cells: [
+                  DataCell(Text(tag.db.name)),
+                  DataCell(CircleColor(
+                    circleSize: 20,
+                    elevation: 0,
+                    color: Color(tag.db.color),
+                  )),
+                ],
+              );
+            }).toList(),
+          ),
+          SizedBox(height: 10),
+          Row(
+            mainAxisAlignment: MainAxisAlignment.end,
+            children: <Widget>[
+              SizedBox(width: 5),
+              MyButton.cancel(onPressed: () => Navigator.of(context).pop()),
+            ],
+          ),
+        ],
+      ),
+    );
+  }
+
+  getData() async {
+    tags = await widget.tagGroup.tags;
+    setState(() {});
+  }
+}

lib/widgets/athlete_widgets/athlete_tag_group_widget.dart

 import 'package:encrateia/screens/add_tag_group_screen.dart';
+import 'package:encrateia/screens/show_tag_group_screen.dart';
 import 'package:encrateia/utils/my_button.dart';
 import 'package:flutter/material.dart';
 import 'package:encrateia/models/athlete.dart';
@@ -62,14 +63,16 @@ class _AthleteTagGroupWidgetState extends State<AthleteTagGroupWidget> {
                       color: Color(tagGroup.db.color),
                     )),
                     DataCell(
-                      MyIcon.edit,
+                      tagGroup.db.system ? MyIcon.show : MyIcon.edit,
                       onTap: () async {
                         await Navigator.push(
                           context,
                           MaterialPageRoute(
-                            builder: (context) => AddTagGroupScreen(
-                              tagGroup: tagGroup,
-                            ),
+                            builder: (context) {
+                              if (tagGroup.db.system)
+                              return ShowTagGroupScreen(tagGroup:tagGroup); else
+                              return AddTagGroupScreen(tagGroup: tagGroup);
+                            },
                           ),
                         );
                         getData();