Flutter Favorites

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      debugShowCheckedModeBanner: false,
      home: CupertinoBottomNav(),
    );
  }
}


// My Bottom Navigation Bar:
class CupertinoBottomNav extends StatelessWidget {
  const CupertinoBottomNav({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return CupertinoTabScaffold(
      tabBar: CupertinoTabBar(
        items: const [
          BottomNavigationBarItem(
              icon: Icon(
                Icons.home_filled,
                size: 28,
              ),
              label: 'Home'),
          BottomNavigationBarItem(
              icon: Icon(
                Icons.storage_rounded,
                size: 28,
              ),
              label: 'Favorites'),
        ],
      ),
      tabBuilder: (context, index) {
        switch (index) {
          case 0:
            return CupertinoTabView(builder: (context) => const ListPage());
          case 1:
          default:
            return CupertinoTabView(builder: (context) => const Favorites());
        }
      },
    );
  }
}


// This is my model class of the items which get stored as favorites

class TestItems {
  String name;
  int id;

  TestItems({required this.name, required this.id});

  factory TestItems.fromJson(Map<String, dynamic> json) {
    return TestItems(
      name: json['name'] as String,
      id: json['id'] as int,
    );
  }

  Map<String, dynamic> toMap() {
    return {
      'id': id,
      'name': name,
    };
  }
}


// This is the page where the stored favorite items are displayed.
//You will see that it only refreshes the page when I restart the app.
//I think this is caused by the CupertinoBottomNavigationBar as it works properly with the Material on.
// But I would like to keep the CupertinoBar as I want it to be shown on every page

// Thank you so much for you support!!!

class Favorites extends StatefulWidget {
  const Favorites({Key? key}) : super(key: key);

  @override
  _FavoritesState createState() => _FavoritesState();
}

class _FavoritesState extends State<Favorites> {
  // ignore: prefer_typing_uninitialized_variables
  var database;
  List<TestItems> items = <TestItems>[];

  Future initDb() async {
    database = await openDatabase(
      join(await getDatabasesPath(), 'person_database.db'),
      onCreate: (db, version) {
        return db.execute(
          "CREATE TABLE person(id INTEGER PRIMARY KEY,  name TEXT)",
        );
      },
      version: 1,
    );

    getMechanism().then((value) {
      setState(() {
        items = value;
      });
    });
  }

  Future<List<TestItems>> getMechanism() async {
    final Database db = await database;

    final List<Map<String, dynamic>> maps = await db.query('person');
    return List.generate(maps.length, (i) {
      return TestItems(
        id: maps[i]['id'],
        name: maps[i]['name'] as String,
      );
    });
  }

  Future<void> deleteDB(int id) async {
    final db = await database;
    await db.delete(
      'person',
      where: "id = ?",
      whereArgs: [id],
    );
  }

  // Future<void> updateDB(Mechanism person) async {
  //   final db = await database;

  //   await db.update(
  //     'person',
  //     where: "id = ?",
  //     whereArgs: [person.id],
  //   );
  // }

  @override
  void initState() {
    super.initState();
    initDb();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("Favorites"),
      ),
      body: ListView.builder(
          itemCount: items.length,
          itemBuilder: (context, index) {
            var item = items[index];
            return ListTile(
              title: Text(
                item.name,
              ),
              onTap: () {
                Navigator.push(
                  context,
                  MaterialPageRoute(
                      builder: (context) => ItemDtl(items: item, id: index)),
                );
              },
              trailing: IconButton(
                color: Colors.red,
                icon: const Icon(Icons.delete_forever_rounded),
                onPressed: () {
                  deleteDB(item.id).then((value) {
                    getMechanism().then((value) {
                      setState(() {
                        items = value;
                      });
                    });
                  });
                },
              ),
            );
          }),
    );
  }
}


// This is the Detailpage of the items

class ItemDtl extends StatefulWidget {
  const ItemDtl({Key? key, required this.items, required this.id})
      : super(key: key);

  final TestItems items;
  final int id;

  @override
  _ItemDtlState createState() => _ItemDtlState();
}

class _ItemDtlState extends State<ItemDtl> {
  // ignore: prefer_typing_uninitialized_variables
  var database;

  @override
  void initState() {
    super.initState();

    initDb();
  }

  Future initDb() async {
    database = openDatabase(
      join(await getDatabasesPath(), 'person_database.db'),
      onCreate: (db, version) {
        return db.execute(
          "CREATE TABLE person(id INTEGER PRIMARY KEY,  name TEXT, height TEXT, mass TEXT, hair_color TEXT, skin_color TEXT, eye_color TEXT, birth_year TEXT, gender TEXT)",
        );
      },
      version: 1,
    );
  }

  Future<void> insertEntry(TestItems items) async {
    final Database db = await database;

    await db.insert(
      'person',
      items.toMap(),
      conflictAlgorithm: ConflictAlgorithm.replace,
    );
  }

  Future<void> updateDB(TestItems items) async {
    final db = await database;

    await db.update(
      'person',
      items.toMap(),
      where: "id = ?",
      whereArgs: [items.id],
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        centerTitle: true,
        title: Text(widget.items.name),
      ),
      body: Padding(
        padding: const EdgeInsets.all(8.0),
        child: ListView(children: <Widget>[
          TextButton.icon(
            icon: const Icon(Icons.storage),
            label: const Text(
              "Add To Favorites",
            ),
            onPressed: () {
              insertEntry(widget.items);
            },
          ),
          Text(
            "Name: ${widget.items.name}",
          ),
        ]),
      ),
    );
  }
}

// This is the page where user is albe to store individuall list items as favorites.

class ListPage extends StatefulWidget {
  const ListPage({Key? key}) : super(key: key);

  @override
  _ListPageState createState() => _ListPageState();
}

class _ListPageState extends State<ListPage> {
  TextEditingController searchController = TextEditingController();
  List<TestItems> shownList = <TestItems>[
    TestItems(name: 'Test', id: 1),
    TestItems(name: 'Test2', id: 2),
    TestItems(name: 'Test3', id: 3)
  ];
  List<TestItems> initialData = <TestItems>[
    TestItems(name: 'Test', id: 1),
    TestItems(name: 'Test2', id: 2),
    TestItems(name: 'Test3', id: 3)
  ];

  void queryPeople(String queryString) {
    if (kDebugMode) {
      print("queryString = $queryString");
    }

    setState(() {
      shownList = initialData.where((string) {
        if (string.name.toLowerCase().contains(queryString.toLowerCase())) {
          return true;
        } else {
          return false;
        }
      }).toList();
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Detail'),
      ),
      body: Column(
        children: <Widget>[
          TextButton.icon(
            label: const Text('Favorites'),
            icon: const Icon(
              Icons.storage,
            ),
            onPressed: () {
              Navigator.push(
                context,
                MaterialPageRoute(builder: (context) => const Favorites()),
              );
            },
          ),
          Expanded(
            child: ItemList(
              item: shownList,
            ),
          ),
        ],
      ),
    );
  }
}

class ItemList extends StatelessWidget {
  final List<TestItems> item;

  const ItemList({Key? key, required this.item}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      itemCount: item.length,
      itemBuilder: (context, index) {
        var items = item[index];
        var name = items.name;
        return ListTile(
          title: Text(
            name,
          ),
          onTap: () {
            items.id = index;
            Navigator.push(
              context,
              MaterialPageRoute(
                  builder: (context) => ItemDtl(
                        id: index,
                        items: items,
                      )),
            );
          },
        );
      },
    );
  }
}