How to retrieve particular data from id on flutter - flutter

Question

How to retrieve particular data from id on flutter and want to show data inside list view. I have created view, insert, delete and update operations.i used sqflite
my code is below.
main.dart file
class _SqliteAppState extends State<SqliteApp> {
int? selectedId;
final textController = TextEditingController();
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: TextField(
controller: textController,
),
),
body: Center(
child: FutureBuilder<List<Grocery>>(
future: DatabaseHelper.instance.getGroceries(),
builder: (BuildContext context,
AsyncSnapshot<List<Grocery>> snapshot) {
if (!snapshot.hasData) {
return Center(child: Text('Loading...'));
}
return snapshot.data!.isEmpty
? Center(child: Text('No Groceries in List.'))
: ListView(
children: snapshot.data!.map((grocery) {
return Center(
child: Card(
color: selectedId == grocery.id
? Colors.white70
: Colors.white,
child: ListTile(
title: Text(grocery.name),
onTap: () {
setState(() {
if (selectedId == null) {
textController.text = grocery.name;
selectedId = grocery.id;
} else {
textController.text = '';
selectedId = null;
}
});
},
onLongPress: () {
setState(() {
DatabaseHelper.instance.remove(grocery.id!);
});
},
),
),
);
}).toList(),
);
}),
),
floatingActionButton: FloatingActionButton(
child: Icon(Icons.save),
onPressed: () async {
selectedId != null
? await DatabaseHelper.instance.update(
Grocery(id: selectedId, name: textController.text),
)
: await DatabaseHelper.instance.add(
Grocery(name: textController.text),
);
setState(() {
textController.clear();
selectedId = null;
});
},
),
),
);
}
The model class code is below
Grocery({this.id, required this.name});
factory Grocery.fromMap(Map<String, dynamic> json) => new Grocery(
id: json['id'],
name: json['name'],
);
Map<String, dynamic> toMap() {
return {
'id': id,
'name': name,
}; } }
This is my db_helper class code. I have created view, insert, delete and update operations.
class DatabaseHelper {
DatabaseHelper._privateConstructor();
static final DatabaseHelper instance = DatabaseHelper._privateConstructor();
static Database? _database;
Future<Database> get database async => _database ??= await _initDatabase();
Future<Database> _initDatabase() async {
Directory documentsDirectory = await getApplicationDocumentsDirectory();
String path = join(documentsDirectory.path, 'groceries.db');
return await openDatabase(
path,
version: 1,
onCreate: _onCreate,
);
}
Future _onCreate(Database db, int version) async {
await db.execute('''
CREATE TABLE groceries(
id INTEGER PRIMARY KEY,
name TEXT
)
''');
}
Future<List<Grocery>> getGroceries() async {
Database db = await instance.database;
var groceries = await db.query('groceries', orderBy: 'name');
List<Grocery> groceryList = groceries.isNotEmpty
? groceries.map((c) => Grocery.fromMap(c)).toList()
: [];
return groceryList;
}
Future<int> add(Grocery grocery) async {
Database db = await instance.database;
return await db.insert('groceries', grocery.toMap());
}
Future<int> remove(int id) async {
Database db = await instance.database;
return await db.delete('groceries', where: 'id = ?', whereArgs: [id]);
}
Future<int> update(Grocery grocery) async {
Database db = await instance.database;
return await db.update('groceries', grocery.toMap(),
where: "id = ?", whereArgs: [grocery.id]);
}
}

Answer 1

You can use this function to get the data by id:
Future<List<Grocery>> getGrocerieById(int id) async {
Database db = await instance.database;
var groceries =
await db.query('groceries', where: 'id = ?', whereArgs: [id]);
List<Grocery> groceryList = groceries.isNotEmpty
? groceries.map((c) => Grocery.fromMap(c)).toList()
: [];
return groceryList;
}