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| import 'package:flutter/material.dart';
import 'package:flutter_demo/provider/main_provider.dart';
import 'package:provider/provider.dart';
void main() {
runApp(MaterialApp(
title: 'demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
//定义作用区间 只绘制顶层home
home: MultiProvider(
providers: [
ChangeNotifierProvider(builder: (_) => MainProvider()),
],
child: Home(),
),
));
}
class Home extends StatefulWidget {
@override
_HomeState createState() => new _HomeState();
}
class _HomeState extends State<Home> {
// int curNum = 0;
int curNum;
@override
void initState() {
super.initState();
//TODO
}
void add() {
setState(() {
curNum += 1;
});
//TODO
}
void minus() {
setState(() {
curNum -= 1;
});
//TODO
}
@override
Widget build(BuildContext context) {
//定义provider 实例化
MainProvider provider = Provider.of<MainProvider>(context);
curNum = provider.curNum;
return new Scaffold(
appBar: new AppBar(
title: new Text('demo'),
),
body: Column(
children: <Widget>[
Add(),
// Add(
// add: add,
// ),
Container(
child: Text(
'$curNum',
style: TextStyle(fontSize: 30),
),
),
Minus(),
// Minus(
// minus: minus,
// ),
],
),
);
}
}
class Minus extends StatelessWidget {
const Minus({
Key key,
// this.minus,
}) : super(key: key);
// final int curNum;
// final VoidCallback minus;
@override
Widget build(BuildContext context) {
MainProvider provider = Provider.of<MainProvider>(context);
return Container(
child: Container(
child: FlatButton(
child: Text(
'-',
style: TextStyle(fontSize: 30),
),
onPressed: () {
provider.minus();
},
),
),
);
}
}
class Add extends StatelessWidget {
const Add({
Key key,
// this.add,
}) : super(key: key);
// final int curNum;
// final VoidCallback add;
@override
Widget build(BuildContext context) {
MainProvider provider = Provider.of<MainProvider>(context);
return Container(
child: Container(
child: FlatButton(
child: Text(
'+',
style: TextStyle(fontSize: 30),
),
onPressed: () {
provider.add();
},
),
),
);
}
}
|
