flutter stateful widget
class YellowBird extends StatefulWidget {
const YellowBird({ Key key }) : super(key: key);
@override
_YellowBirdState createState() => _YellowBirdState();
}
class _YellowBirdState extends State<YellowBird> {
@override
Widget build(BuildContext context) {
return Container(color: const Color(0xFFFFE306));
}
}conditionalstatement in widget flutter
Container(
color: Colors.white,
child: ('condition')
? Widget1(...)
: Widget2(...)
)make stateful widget flutter
class MyClass extends StatefulWidget {
@override
MyClassState createState() => new MyClassState();
}
class MyClassState extends State<MyClass> {
//Widgets and other code here
}flutter state management
// providers/provider.dart
class Products with ChangeNotifier {
List<Product> _items = [
...dummy data
];
List<Product> get items {
return [..._items];
}
Product findById(String id) { //this func will be used for getting product with id
return _items.firstWhere((element) => element.id == id);
}
}
// main.dart (this needs to be the topmost file wwhose children need to access the state
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ChangeNotifierProvider(
create: (ctx) => Products(), // pass here the provider you want to access
child: MaterialApp(
title: 'Flutter Demo',
home: ProductsOverviewScreen(),
),
);
}
}
// in the file you want to access the state
class ProductDetailScreen extends StatelessWidget {
@override
Widget build(BuildContext context) {
final productId = ModalRoute.of(context)!.settings.arguments as String;
final loadedProduct =
Provider.of<Products>(context).findById(productId);
return Scaffold(
appBar: AppBar(
title: Text(loadedProduct.title),
),
);
}
}Copyright © 2021 Codeinu
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