一统天下 flutter - widget Builder: StatefulBuilder - 有状态的 Builder
一统天下 flutter - widget Builder: StatefulBuilder - 有状态的 Builder
示例如下:
lib\widget\builder\stateful_builder.dart
/*
* StatefulBuilder - 有状态的 Builder
*
* 请先了解 Builder，参见 builder.dart
*/
import 'package:flutter/material.dart';
import '../../helper.dart';
class StatefulBuilderDemo extends StatefulWidget {
const StatefulBuilderDemo({Key? key}) : super(key: key);
@override
_StatefulBuilderDemoState createState() => _StatefulBuilderDemoState();
}
class _StatefulBuilderDemoState extends State<StatefulBuilderDemo> {
@override
Widget build(BuildContext context) {
int counter = 0;
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
MyText('counter: $counter'),
Builder(
builder: (BuildContext context) {
/// 相对于 Builder 来说，StatefulBuilder 会多出一个 StateSetter 类型的对象
return StatefulBuilder(
builder: (BuildContext context, StateSetter setState) {
return TextButton(
onPressed: () {
/// 可以通过 StateSetter 对象修改状态，其会让对应的 StatefulBuilder 重绘，而 StatefulBuilder 之外的部分不会重绘
setState(() => { counter++ });
},
child: Text('counter: $counter')
);
}
);
},
),
],
);
}
}
