Flutter-状态管理-scoped_model

scoped_model: ^2.0.0

import 'package:scoped_model/scoped_model.dart';

class CounterModel extends Model {
  int _counter = 0;

  int get counter => _counter;

  void increment() {
    _counter++;
    print(_counter);
    notifyListeners();
  }
}

import 'package:flutter/material.dart';
import 'package:scoped_model/scoped_model.dart';
import 'package:stream_demo/model/counter_model.dart';
import 'page/home_page.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
   return ScopedModel<CounterModel>(model: CounterModel(),child: MaterialApp(
     title: 'Flutter Demo',
     theme: ThemeData(
       primarySwatch: Colors.blue,
     ),
     home: const MyHomePage(title: 'Flutter Demo Home Page'),
   ),);

  }
}

import 'package:flutter/material.dart';
import 'package:scoped_model/scoped_model.dart';
import 'package:stream_demo/model/counter_model.dart';

import 'detail_page.dart';

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    final countModel = ScopedModel.of<CounterModel>(context);

    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ScopedModelDescendant<CounterModel>(
                builder: (context, child, model) {
                  return OutlinedButton(
                      onPressed: (){
                        Navigator.push(context, MaterialPageRoute(builder: (context) {
                          return const MyDetailPage(title: "我是详情页面");
                        }));
                      }, child: Text("详情页"));
                }),
            const Text(
              'You have pushed the button this many times:',
            ),
            ScopedModelDescendant<CounterModel>(
                builder: (context, child, model) {
                  return Text(
                    model.counter.toString(),
                    style: Theme.of(context).textTheme.headlineMedium,
                  );
                }),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          print("11111");
          countModel.increment();
        },
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

import 'package:flutter/material.dart';
import 'package:scoped_model/scoped_model.dart';
import 'package:stream_demo/model/counter_model.dart';

class MyDetailPage extends StatefulWidget {
  const MyDetailPage({super.key, required this.title});

  final String title;

  @override
  State<MyDetailPage> createState() => _MyDetailPageState();
}

class _MyDetailPageState extends State<MyDetailPage> {
  @override
  Widget build(BuildContext context) {
    final countModel = ScopedModel.of<CounterModel>(context);

    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            ScopedModelDescendant<CounterModel>(
                builder: (context, child, model) => Text(
                      model.counter.toString(),
                      style: Theme.of(context).textTheme.headlineMedium,
                    )),
            FloatingActionButton(
              onPressed: countModel.increment,
              tooltip: 'Increment',
              child: const Icon(Icons.add),
            )
          ],
        ),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}