Feature/Fix-Invalid-TimeProgress-Name (#3)

Throw Exception when creating time progress with empty or null name.
Handle Exception when user creates new time progress or changes name.

Signed-off-by Andreas Fahrecker <AndreasFahrecker@gmail.com>

lib/models/app_exceptions.dart

@@ -0,0 +1,7 @@
+class TimeProgressInvalidNameException implements Exception {
+  final invalidName;
+
+  TimeProgressInvalidNameException(this.invalidName);
+
+  String errMsg() => "The name of a TimeProgress can't be: $invalidName";
+}

lib/models/time_progress.dart

@@ -1,4 +1,5 @@
 import 'package:meta/meta.dart';
+import 'package:time_progress_tracker/models/app_exceptions.dart';
 import 'package:time_progress_tracker/persistence/time_progress_entity.dart';
 import 'package:time_progress_tracker/uuid.dart';
 
@@ -10,11 +11,15 @@ class TimeProgress {
   final DateTime endTime;
 
   TimeProgress(this.name, this.startTime, this.endTime, {String id})
-      : id = id ?? Uuid().generateV4();
+      : id = id ?? Uuid().generateV4() {
+    if (this.name == null || this.name == "") {
+      throw new TimeProgressInvalidNameException(this.name);
+    }
+  }
 
   factory TimeProgress.initialDefault() {
     int thisYear = DateTime.now().year;
-    return TimeProgress("", DateTime(thisYear - 1), DateTime(thisYear + 1));
+    return TimeProgress("Initial Name", DateTime(thisYear - 1), DateTime(thisYear + 1));
   }
 
   TimeProgress copyWith(

lib/screens/progress_creation_screen.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_redux/flutter_redux.dart';
 import 'package:time_progress_tracker/actions/actions.dart';
+import 'package:time_progress_tracker/models/app_exceptions.dart';
 import 'package:time_progress_tracker/models/app_state.dart';
 import 'package:time_progress_tracker/models/time_progress.dart';
 import 'package:time_progress_tracker/screens/progress_dashboard_screen.dart';
@@ -22,6 +23,8 @@ class _ProgressCreationScreenState extends State<ProgressCreationScreen> {
   DateTime pickedEndTime = DateTime(
       DateTime.now().year + 1, DateTime.now().month, DateTime.now().day);
 
+  bool _validName = true;
+
   Future<DateTime> _selectDate(
       BuildContext context, DateTime initialDate) async {
     return await showDatePicker(
@@ -32,10 +35,17 @@ class _ProgressCreationScreenState extends State<ProgressCreationScreen> {
   }
 
   void _createTimeProgress(BuildContext context) {
-    StoreProvider.of<AppState>(context).dispatch(AddTimeProgressAction(
-      TimeProgress(_nameController.text, pickedStartTime, pickedEndTime),
-    ));
+    try {
+      TimeProgress tpToCreate =
+          TimeProgress(_nameController.text, pickedStartTime, pickedEndTime);
+      StoreProvider.of<AppState>(context)
+          .dispatch(AddTimeProgressAction(tpToCreate));
       Navigator.pushNamed(context, ProgressDashboardScreen.routeName);
+    } on TimeProgressInvalidNameException catch (e) {
+      setState(() {
+        _validName = false;
+      });
+    }
   }
 
   @override
@@ -60,7 +70,12 @@ class _ProgressCreationScreenState extends State<ProgressCreationScreen> {
               child: TextField(
                 controller: _nameController,
                 decoration: InputDecoration(
-                    border: OutlineInputBorder(), labelText: "Progress Name"),
+                  border: OutlineInputBorder(),
+                  labelText: "Progress Name",
+                  errorText: _validName
+                      ? null
+                      : "The Name of the Time Progress has to be set.",
+                ),
               ),
             ),
             Expanded(

lib/screens/progress_detail_screen.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_redux/flutter_redux.dart';
 import 'package:redux/redux.dart';
 import 'package:time_progress_tracker/actions/actions.dart';
+import 'package:time_progress_tracker/models/app_exceptions.dart';
 import 'package:time_progress_tracker/models/app_state.dart';
 import 'package:time_progress_tracker/models/time_progress.dart';
 import 'package:time_progress_tracker/screens/progress_dashboard_screen.dart';
@@ -30,10 +31,13 @@ class ProgressDetailScreen extends StatefulWidget {
 }
 
 class _ProgressDetailScreenState extends State<ProgressDetailScreen> {
-  final TextEditingController _nameController = TextEditingController();
   bool _isBeingEdited = false;
+  final TextEditingController _nameController = TextEditingController();
+
   TimeProgress _editedProgress = TimeProgress.initialDefault();
 
+  bool _validName = true;
+
   void _onStartDateChanged(DateTime picked) {
     if (picked != null) {
       setState(() {
@@ -118,10 +122,18 @@ class _ProgressDetailScreenState extends State<ProgressDetailScreen> {
   void initState() {
     super.initState();
     _nameController.addListener(() {
-      this.setState(() {
-        this._editedProgress =
-            this._editedProgress.copyWith(name: _nameController.text);
+      try {
+        TimeProgress editedProgress =
+            _editedProgress.copyWith(name: _nameController.text);
+        setState(() {
+          _editedProgress = editedProgress;
+          _validName = true;
         });
+      } on TimeProgressInvalidNameException catch (e) {
+        setState(() {
+          _validName = false;
+        });
+      }
     });
   }
 
@@ -152,7 +164,11 @@ class _ProgressDetailScreenState extends State<ProgressDetailScreen> {
                           controller: _nameController,
                           decoration: InputDecoration(
                             border: OutlineInputBorder(),
-                              labelText: "Progress Name"),
+                            labelText: "Progress Name",
+                            errorText: _validName
+                                ? null
+                                : "The Name of the Time Progress has to be set.",
+                          ),
                         )
                       : FittedBox(
                           fit: BoxFit.fitWidth,
@@ -205,7 +221,8 @@ class _ProgressDetailScreenState extends State<ProgressDetailScreen> {
       floatingActionButtonLocation: FloatingActionButtonLocation.centerFloat,
       floatingActionButton: _isBeingEdited
           ? ProgressDetailFabEditingRow(
-              onSave: () => _onSaveTimeProgress(store, args.id),
+              onSave: () =>
+                  _validName ? _onSaveTimeProgress(store, args.id) : null,
               onCancelEdit: () =>
                   _showCancelEditTimeProgressDialog(store.state, args.id),
             )

lib/selectors/time_progress_selectors.dart

@@ -4,5 +4,8 @@ import 'package:time_progress_tracker/models/time_progress.dart';
 List<TimeProgress> timeProgressListSelector(AppState state) =>
     state.timeProgressList;
 
-TimeProgress timeProgressByIdSelector(AppState state, String id) =>
-    state.timeProgressList.firstWhere((timeProgress) => timeProgress.id == id);
+TimeProgress timeProgressByIdSelector(AppState state, String id) {
+  if (state.timeProgressList.length < 1) return null;
+  return state.timeProgressList
+      .firstWhere((timeProgress) => timeProgress.id == id);
+}