（四）Flutter Redux 中实现简单换肤

在之前的（二）Flutter Redux 中的 combineReducers文章中我们对redux有了初步的认识和使用，这次主要是将 combineReducers 和 系统换肤 结合起来使用。

第一步：声明一个State类

/// 定义一个state
class ReduxState {

  ThemeData themeData;
  
  ReduxState({this.themeData});
  
}

/// 定义action，将action放到theme_redux类里去定义

/// 定义reducer
ReduxState getReduce(ReduxState state, action) {
  
  return ReduxState(
    themeData: ThemeDataReducer(state.themeData, action)
  );
}

第二步：声明一个处理换肤的Reducer类 theme_redux.dart

/// 换肤Action和函数绑定起来
final ThemeDataReducer = combineReducers([
  TypedReducer(_refreshTheme)
]);

/// 换肤方法
ThemeData _refreshTheme(ThemeData themeData, ThemeRefreshAction action) {
  themeData = action.themeData;
  return themeData;
}

/// 换肤Action
class ThemeRefreshAction {
  ThemeData themeData;
  ThemeRefreshAction(this.themeData);
}

第三步：创建全局Store，并将Store跟根Widget关联

main() {
  /// 创建全局Store
  final store = Store(
      getReduce,
      initialState: ReduxState(
        /// 初始话默认的皮肤数据
        themeData: ThemeData(primaryColor: Colors.black)
      )
  );
  runApp(ReduxDemo3(store,));
}

class ReduxDemo3 extends StatelessWidget {

  final Store store;
  ReduxDemo3(this.store);

  @override
  Widget build(BuildContext context) {
    return StoreProvider(
        store: store,
        /// StoreBuilder后要跟上我们定义的那个State类，要不会报错，
        child: StoreBuilder(builder: (BuildContext context, Store store){
          return MaterialApp(
            title: 'ReduxDemo3',
            /// 这边的皮肤数据主要从store中去取
            theme: store.state.themeData,
            home: FirstPage(),
          );
        })
    );
  }
}

第四步：界面构建，变更皮肤的同时变更文本颜色

class FirstPageState extends State {
  @override
  Widget build(BuildContext context) {

    return StoreBuilder(
        builder: (BuildContext context, Store store){
          return Scaffold(
            appBar: AppBar(
              title: Text("ReduxDemo3"),
            ),
            body: Center(
                child: Column(
                  children: _btnList(store),
                )
            ),
          );
        }
    );
  }

  /// 构建按钮
  _btnList(Store store) {
    List list = List();
    for(int i = 0; i < getThemeListColors().length; i++) {
      list.add(SizedBox(height: 20,));
      list.add(_buildBtns(store, i));
    }
    return list;
  }

  /// 改变皮肤颜色的同时也修改文本的颜色
  Widget _buildBtns(Store store, int index) {
    return FlatButton(
        onPressed: (){
          store.dispatch(ThemeRefreshAction(ThemeData(
            /// store发出修改皮肤的action
            primaryColor: getThemeListColors()[index]
          )));
        },
        child: Text(
         getThemeListNames()[index],
          style: TextStyle(
            /// 文本的颜色从store中获取
            color: store.state.themeData.primaryColor
          ),
        )
    );
  }

  /// 颜色值数组
  static List getThemeListColors() {
    return [
      Colors.black,
      Colors.red,
      Colors.orange,
      Colors.brown,
      Colors.blue,
    ];
  }

  /// 颜色名数组
  static List getThemeListNames() {
    return [
      "black",
      "red",
      "orange",
      "brown",
      "blue",
    ];
  }
}

效果

代码

代码