fix: canteen view removes item select listener on view exit

src/app/modules/data/list/food-data-list.component.ts

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022 StApps
+ * Copyright (C) 2023 StApps
  * This program is free software: you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
  * Software Foundation, version 3.
@@ -12,10 +12,11 @@
  * You should have received a copy of the GNU General Public License along with
  * this program. If not, see <https://www.gnu.org/licenses/>.
  */
-import {Component} from '@angular/core';
+import {Component, OnDestroy, OnInit} from '@angular/core';
 import {MapPosition} from '../../map/position.service';
 import {SearchPageComponent} from './search-page.component';
 import {Geolocation} from '@capacitor/geolocation';
+import {Subscription} from 'rxjs';
 
 /**
  * Presents a list of places for eating/drinking
@@ -24,15 +25,19 @@ import {Geolocation} from '@capacitor/geolocation';
   templateUrl: 'search-page.html',
   styleUrls: ['../../data/list/search-page.scss'],
 })
-export class FoodDataListComponent extends SearchPageComponent {
+export class FoodDataListComponent extends SearchPageComponent implements OnInit, OnDestroy {
   title = 'canteens.title';
 
   showNavigation = false;
 
+  locationWatch?: Subscription;
+
   /**
    * Sets the forced filter to present only places for eating/drinking
    */
-  initialize() {
+  ngOnInit() {
+    this.locationWatch?.unsubscribe();
+    this.locationWatch = this.createLocationWatch();
     this.showDefaultData = true;
 
     this.sortQuery = [
@@ -92,29 +97,36 @@ export class FoodDataListComponent extends SearchPageComponent {
         },
       ];
     }
+
+    super.ngOnInit();
+  }
+
+  private createLocationWatch(): Subscription {
+    return this.positionService
+      .watchCurrentLocation(this.constructor.name, {enableHighAccuracy: false, maximumAge: 1000})
+      .subscribe({
+        next: (position: MapPosition) => {
+          this.positionService.position = position;
+        },
+        error: async _error => {
+          this.positionService.position = undefined;
+          await Geolocation.checkPermissions();
+        },
+      });
   }
 
   async ionViewWillEnter() {
     await super.ionViewWillEnter();
-    this.subscriptions.push(
+    this.locationWatch?.unsubscribe();
-      this.positionService
+    this.locationWatch = this.createLocationWatch();
-        .watchCurrentLocation(this.constructor.name, {enableHighAccuracy: false, maximumAge: 1000})
-        .subscribe({
-          next: (position: MapPosition) => {
-            this.positionService.position = position;
-          },
-          error: async _error => {
-            this.positionService.position = undefined;
-            await Geolocation.checkPermissions();
-          },
-        }),
-    );
   }
 
   ionViewWillLeave() {
-    void this.positionService.clearWatcher(this.constructor.name);
+    this.locationWatch?.unsubscribe();
-    for (const sub of this.subscriptions) {
+  }
-      sub.unsubscribe();
+
-    }
+  ngOnDestroy() {
+    super.ngOnDestroy();
+    this.locationWatch?.unsubscribe();
   }
 }