added incremental notification ids stored in the recipeStep for cancelling

lib/entities/PizzaEvent.dart

@@ -5,6 +5,7 @@ import 'package:pizzaplanner/entities/PizzaRecipe/PizzaRecipe.dart';
 import 'package:pizzaplanner/main.dart';
 
 import 'package:timezone/timezone.dart' as tz;
+import 'dart:math';
 
 part 'PizzaEvent.g.dart';
 
@@ -49,9 +50,12 @@ class PizzaEvent extends HiveObject{
         .fold(0, (a, b) => a+b));
     stepTime = stepTime.subtract(durationToFirstStep);
 
+    final List<PendingNotificationRequest> pendingNotificationRequests = await flutterLocalNotificationsPlugin.pendingNotificationRequests();
+    int notificationId = pendingNotificationRequests.map((pendingNotification) => pendingNotification.id).fold(0, max);
+
     for (var recipeStep in this.recipe.recipeSteps) {
       await flutterLocalNotificationsPlugin.zonedSchedule(
-          "${name}_${recipeStep.name}_${dateTime.millisecondsSinceEpoch}".hashCode,
+          notificationId,
           recipeStep.name,
           null,
           stepTime,
@@ -60,7 +64,9 @@ class PizzaEvent extends HiveObject{
           uiLocalNotificationDateInterpretation:
           UILocalNotificationDateInterpretation.absoluteTime
       );
+      recipeStep.notificationId = notificationId;
       stepTime = stepTime.add(Duration(seconds: recipeStep.getCurrentWaitInSeconds()));
+      notificationId++;
     }
   }
 }

lib/entities/PizzaRecipe/RecipeStep.dart

@@ -34,9 +34,11 @@ class RecipeStep extends HiveObject {
 
   @HiveField(8)
   DateTime? completedOn;
-
   bool get completed => _completed();
 
+  @HiveField(9)
+  int notificationId = -1;
+
   RecipeStep(this.name, this.description, this.waitDescription, this.waitUnit, this.waitMin, this.waitMax, this.subSteps) {
     waitValue = waitMin;
   }

lib/pages/AddPizzaEventPage.dart

@@ -6,6 +6,7 @@ import 'package:fluttericon/font_awesome5_icons.dart';
 
 import 'package:pizzaplanner/entities/PizzaEvent.dart';
 import 'package:pizzaplanner/entities/PizzaRecipe/PizzaRecipe.dart';
+import 'package:pizzaplanner/main.dart';
 import 'package:pizzaplanner/util.dart';
 
 import 'package:hive/hive.dart';
@@ -151,6 +152,7 @@ class AddPizzaEventPageState extends State<AddPizzaEventPage> {
                           child: TextButton(
                             child: Text("Review", style: TextStyle(color: Colors.white)),
                             onPressed: () async {
+
                               if (this.name.length == 0){
                                 setState(() { this.nameValidation = true; });
                                 return;