How to block the repeated item in flutter? - flutter

Question

I saw this code in KindaCode. This is link ( https://www.kindacode.com/article/flutter-hive-database/#single__comments ) . I want the added item not to be added again. How can I do that? This code, we just add items and delete and olsa upgrade. We just write the name and quantity and adding the item. But if i write the same name as the other one, adds again.
// main.dart
import 'package:flutter/material.dart';
import 'package:hive_flutter/hive_flutter.dart';
void main() async {
WidgetsFlutterBinding.ensureInitialized();
await Hive.initFlutter();
await Hive.openBox('shopping_box'); //verileri icerisinde barındırıcak kutuyu olusturma
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'KindaCode.com',
theme: ThemeData(
primarySwatch: Colors.green,
),
home: const HomePage(),
);
}
}
// Home Page
class HomePage extends StatefulWidget {
const HomePage({Key? key}) : super(key: key);
#override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
List<Map<String, dynamic>> _items = [];
final _shoppingBox = Hive.box('shopping_box');
#override
void initState() {
super.initState();
_refreshItems(); // Load data when app starts
}
// Get all items from the database
void _refreshItems() {
final data = _shoppingBox.keys.map((key) {
final value = _shoppingBox.get(key);
return {"key": key, "name": value["name".toLowerCase()], "quantity": value['quantity']};
}).toList(); //verileri listede gosterme
setState(() {
_items = data.reversed.toList(); //en sondan en eskiye dogru siralamak icin reversed
// we use "reversed" to sort items in order from the latest to the oldest
});
}
// Create new item
Future<void> _createItem(Map<String, dynamic> newItem) async {
await _shoppingBox.add(newItem); //yeni veri olusturma
_refreshItems(); // update the UI
}
// Retrieve a single item from the database by using its key
// Our app won't use this function but I put it here for your reference
// Update a single item
Future<void> _updateItem(int itemKey, Map<String, dynamic> item) async {
await _shoppingBox.put(itemKey, item); //tablo icerisine veriyi koyma
_refreshItems(); // Update the UI
}
// Delete a single item
Future<void> _deleteItem(int itemKey) async {
await _shoppingBox.delete(itemKey);
_refreshItems(); // update the UI
// Display a snackbar
ScaffoldMessenger.of(context).showSnackBar( //ekranin alt kisminda itemin silindigini belirtme
const SnackBar(content: Text('An item has been deleted')));
}
// TextFields' controllers
final TextEditingController _nameController = TextEditingController();
final TextEditingController _quantityController = TextEditingController();
void _showForm(BuildContext ctx, int? itemKey) async { //yeni item eklerken ve butona basildiginda tetiklenen flotingbutton
// itemKey == null -> create new item
// itemKey != null -> update an existing item
if (itemKey != null) { //itemi guncelleme
final existingItem =
_items.firstWhere((element) => element['key'] == itemKey);
_nameController.text = existingItem['name'];
_quantityController.text = existingItem['quantity'];
}
showModalBottomSheet(
context: ctx,
elevation: 5,
isScrollControlled: true,
builder: (_) => Container(
padding: EdgeInsets.only(
bottom: MediaQuery.of(ctx).viewInsets.bottom,
top: 15,
left: 15,
right: 15),
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.end,
children: [
TextField(
controller: _nameController,
decoration: const InputDecoration(hintText: 'Name'),
),
const SizedBox(
height: 10,
),
TextField(
controller: _quantityController,
keyboardType: TextInputType.number,
decoration: const InputDecoration(hintText: 'Quantity'),
),
const SizedBox(
height: 20,
),
ElevatedButton( //here the create or upgrade the item
onPressed: () async {
// Save new item
if (itemKey == null) { //yeni item
if() {
_createItem({
"name": _nameController.text,
"quantity": _quantityController.text
});
}
}
// update an existing item
if (itemKey != null) {
_updateItem(itemKey, {
'name': _nameController.text.trim(),
'quantity': _quantityController.text.trim()
});
}
// Clear the text fields
_nameController.text = '';
_quantityController.text = '';
Navigator.of(context).pop(); // Close the bottom sheet
},
child: Text(itemKey == null ? 'Create New' : 'Update'),
),
const SizedBox(
height: 15,
)
],
),
));
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('KindaCode.com'),
),
body: _items.isEmpty
? const Center(
child: Text(
'No Data',
style: TextStyle(fontSize: 30),
),
)
: ListView.builder(
// the list of items
itemCount: _items.length,
itemBuilder: (_, index) {
final currentItem = _items[index];
return Card(
color: Colors.orange.shade100,
margin: const EdgeInsets.all(10),
elevation: 3,
child: ListTile(
title: Text(currentItem['name']),
subtitle: Text(currentItem['quantity'].toString()),
trailing: Row(
mainAxisSize: MainAxisSize.min,
children: [
// Edit button
IconButton(
icon: const Icon(Icons.edit), //düzenleme butonu
onPressed: () =>
_showForm(context, currentItem['key'])),
// Delete button
IconButton(
icon: const Icon(Icons.delete),
onPressed: () => _deleteItem(currentItem['key']),
),
],
)),
);
}),
// Add new item button
floatingActionButton: FloatingActionButton( //ekranin alt kosesinde bulunan ekleme butonu
onPressed: () => _showForm(context, null),
child: const Icon(Icons.add),
),
);
}
} ```