下面是flutter自带demo，大家应该很熟悉了

• 如果对基础概念不明白的可以去我第一篇文章了解一下

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(title: 'Flutter Demo Home Page'),
      debugShowCheckedModeBanner: false,
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('$_counter'),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

cunter fish redux 版

• 基础目录

1. action.dart
2. effect.dart(本例中非必须)
3. page.dart
4. reducer.dart
5. state.dart
6. view.dart

action.dart

enum CounterAction { add, onAdd }

class CounterActionCreator {
  //reducer使用
  static Action add() {
    return const Action(CounterAction.add);
  }
  //effect使用
  static Action onAdd() {
    return const Action(CounterAction.onAdd);
  }
}

state.dart

class CounterState implements Cloneable<CounterState> {
  int count = 0;

  @override
  CounterState clone() {
    return CounterState()..count = count;
  }
}

CounterState initState(Map<String, dynamic> args){
  //什么也没做，只是初始化数据
  return CounterState();
}

reducer.dart

Reducer<CounterState> buildReducer() {
  return asReducer<CounterState>(<Object, Reducer<CounterState>>{
    CounterAction.add: _add,
  });
}

CounterState _add(CounterState state, Action action) {
  final CounterState newState = state.clone();
  newState.count = ++state.count;
  return newState;
}

effect.dart

Effect<CounterState> buildEffect() {
  return combineEffects(<Object, Effect<CounterState>>{
    CounterAction.onAdd: _onAdd,
  });
}

void _onAdd(Action action, Context<CounterState> ctx) {
  print("_onAdd");
  ctx.dispatch(CounterActionCreator.add());
}

view.dart

Widget buildView(
    CounterState state, Dispatch dispatch, ViewService viewService) {
  return Scaffold(
    appBar: AppBar(
      title: Text('CounterFishRedux'),
    ),
    body: Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Text(
            state.count.toString(),
          )
        ],
      ),
    ),
    floatingActionButton: FloatingActionButton(
      //发送的action到了Effect中处理
      onPressed: () => dispatch(CounterActionCreator.onAdd()),
      //也可以发action到reducer中处理
      //onPressed: () => dispatch(CounterActionCreator.add()),
      tooltip: 'add',
      child: Icon(Icons.add),
    ),
  );
}

page.dart

class CounterFishReduxPage extends Page<CounterState, Map<String, dynamic>> {
  CounterFishReduxPage()
      : super(
          initState: initState,
          effect: buildEffect(),
          reducer: buildReducer(),
          view: buildView,
        );
}

在view.dart中，用户触发FloatingActionButton的onPress事件，dispatch了名为onAdd的Action，在effect.dart中接收到action，会继续dispatch，到reducer.dart中(这一步非必须，可以直接dispatch到reducer.dart中)，在reducer.dart中，在state中取出state中的数据，处理(加一)后，返回state，数据更新到store中，触发UI更新，最终到view.dart中state中的数据会更新，取出新的数据显示。

​ fish redux适用于中大型项目，这种简单的功能直接用官方的setState即可。

这样就可以单独作为一个page或者component使用，没有逻辑和UI的耦合

demo地址：
另外推荐一个文章：https://blog.csdn.net/Crazy_SunShine/article/details/101430068
demo地址：https://github.com/xuyanhao666/Fish_Redux_Demo/tree/master/fish_redux_addCount