Created DatePickerBtn and Started Using it in ProgressCreationScreen

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

lib/models/app_exceptions.dart

@@ -5,3 +5,14 @@ class TimeProgressInvalidNameException implements Exception {
 
   String errMsg() => "The name of a TimeProgress can't be: $invalidName";
 }
+
+class TimeProgressStartTimeIsNotBeforeEndTimeException implements Exception {
+  final startTime;
+  final endTime;
+
+  TimeProgressStartTimeIsNotBeforeEndTimeException(
+      this.startTime, this.endTime);
+
+  String errMsg() =>
+      "The Start Time has to be before the end time. Therefore these values are invalid: Start Time: $startTime EndTime: $endTime";
+}

lib/models/time_progress.dart

@@ -12,9 +12,11 @@ class TimeProgress {
 
   TimeProgress(this.name, this.startTime, this.endTime, {String id})
       : id = id ?? Uuid().generateV4() {
-    if (this.name == null || this.name == "") {
+    if (this.name == null || this.name == "")
       throw new TimeProgressInvalidNameException(this.name);
-    }
+    if (!this.startTime.isBefore(this.endTime))
+      throw new TimeProgressStartTimeIsNotBeforeEndTimeException(
+          startTime, endTime);
   }
 
   factory TimeProgress.initialDefault() {

lib/screens/progress_creation_screen.dart

@@ -5,10 +5,11 @@ 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/home_screen.dart';
+import 'package:time_progress_tracker/widgets/date_picker_btn.dart';
 
 class ProgressCreationScreen extends StatefulWidget {
   static const routeName = "/progress-creation";
+  static const title = "Create Time Progress";
 
   @override
   State<StatefulWidget> createState() {
@@ -23,15 +24,7 @@ class _ProgressCreationScreenState extends State<ProgressCreationScreen> {
       DateTime.now().year + 1, DateTime.now().month, DateTime.now().day);
 
   bool _validName = true;
-
+  bool _validDates = true;
-  Future<DateTime> _selectDate(
-      BuildContext context, DateTime initialDate) async {
-    return await showDatePicker(
-        context: context,
-        initialDate: initialDate,
-        firstDate: DateTime(DateTime.now().year - 5),
-        lastDate: DateTime(DateTime.now().year + 5));
-  }
 
   void _createTimeProgress(BuildContext context) {
     try {
@@ -44,6 +37,10 @@ class _ProgressCreationScreenState extends State<ProgressCreationScreen> {
       setState(() {
         _validName = false;
       });
+    } on TimeProgressStartTimeIsNotBeforeEndTimeException catch (e) {
+      setState(() {
+        _validDates = false;
+      });
     }
   }
 
@@ -59,11 +56,8 @@ class _ProgressCreationScreenState extends State<ProgressCreationScreen> {
 
     return Scaffold(
       appBar: AppBar(
-        title: Text("Create Time Progress"),
+        title: Text(ProgressCreationScreen.title),
       ),
-      /*drawer: AppDrawer(
-        appVersion: widget.appVersion,
-      ),*/
       body: Container(
         padding: EdgeInsets.all(8),
         child: Column(
@@ -81,25 +75,19 @@ class _ProgressCreationScreenState extends State<ProgressCreationScreen> {
                 ),
               ),
             ),
-            Expanded(
-              child: Text("${_nameController.text}"),
-            ),
             Expanded(
               flex: 1,
               child: Row(
                 children: <Widget>[
                   Expanded(
                     flex: 5,
-                    child: FlatButton(
+                    child: DatePickerBtn(
-                      color: appTheme.accentColor,
+                      leadingString: "Start Date:",
-                      child: Text(
+                      pickedDate: pickedStartTime,
-                          "Start Date: ${pickedStartTime.toLocal().toString().split(" ")[0]}"),
+                      onDatePicked: (DateTime startTime) {
-                      onPressed: () async {
+                        if (startTime != null) {
-                        DateTime dt =
-                            await _selectDate(context, pickedStartTime);
-                        if (dt != null) {
                           setState(() {
-                            pickedStartTime = dt;
+                            pickedStartTime = startTime;
                           });
                         }
                       },
@@ -110,15 +98,13 @@ class _ProgressCreationScreenState extends State<ProgressCreationScreen> {
                   ),
                   Expanded(
                     flex: 5,
-                    child: FlatButton(
+                    child: DatePickerBtn(
-                      color: appTheme.accentColor,
+                      leadingString: "EndDate:",
-                      child: Text(
+                      pickedDate: pickedEndTime,
-                          "End Date: ${pickedEndTime.toLocal().toString().split(" ")[0]}"),
+                      onDatePicked: (DateTime endTime) {
-                      onPressed: () async {
+                        if (endTime != null) {
-                        DateTime dt = await _selectDate(context, pickedEndTime);
-                        if (dt != null) {
                           setState(() {
-                            pickedEndTime = dt;
+                            pickedEndTime = endTime;
                           });
                         }
                       },
@@ -127,8 +113,18 @@ class _ProgressCreationScreenState extends State<ProgressCreationScreen> {
                 ],
               ),
             ),
+            _validDates
+                ? Spacer(
+                    flex: 1,
+                  )
+                : Expanded(
+                    child: Center(
+                      child: Text(
+                          "Your Picked Dates are invalid. The Start Date has to be before the end Date."),
+                    ),
+                  ),
             Spacer(
-              flex: 5,
+              flex: 4,
             )
           ],
         ),

lib/widgets/date_picker_btn.dart

@@ -0,0 +1,31 @@
+import 'package:flutter/material.dart';
+
+class DatePickerBtn extends StatelessWidget {
+  final String leadingString;
+  final DateTime pickedDate;
+  final void Function(DateTime) onDatePicked;
+
+  DatePickerBtn({
+    @required this.leadingString,
+    @required this.pickedDate,
+    @required this.onDatePicked,
+  }) : super();
+
+  @override
+  Widget build(BuildContext context) {
+    ThemeData appTheme = Theme.of(context);
+    return FlatButton(
+      onPressed: () async {
+        onDatePicked(await showDatePicker(
+          context: context,
+          initialDate: pickedDate,
+          firstDate: DateTime(1900),
+          lastDate: DateTime(2100),
+        ));
+      },
+      child: Text(
+          "$leadingString ${pickedDate.toLocal().toString().split(" ")[0]}"),
+      color: appTheme.accentColor,
+    );
+  }
+}