React Native 添加 Redux 支持

0x1 前言

之前写的项目都是人家编写好的脚手架，里面包含项目所需的环境文件，但由于有些东西用不到打包增加软件体积，所以自己从头搭建个环境。是基于 Native Base + react-navigation + Redux 的 React Native 脚手架，现在项目环境如下：

{
  "name": "app",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "start": "react-native start",
    "test": "jest",
    "lint": "eslint ."
  },
  "dependencies": {
    "native-base": "^2.13.4",
    "react": "16.8.6",
    "react-native": "0.60.5",
    "react-native-gesture-handler": "^1.3.0",
    "react-native-keyboard-aware-scroll-view": "^0.9.1",
    "react-native-reanimated": "^1.2.0",
    "react-navigation": "^3.11.1"
  },
  "devDependencies": {
    "@babel/core": "^7.5.5",
    "@babel/runtime": "^7.5.5",
    "@react-native-community/eslint-config": "^0.0.5",
    "babel-eslint": "7.2.3",
    "babel-jest": "^24.8.0",
    "eslint": "4.4.1",
    "eslint-plugin-flowtype": "2.35.0",
    "eslint-plugin-import": "2.7.0",
    "eslint-plugin-jsx-a11y": "6.0.2",
    "eslint-plugin-prettier": "2.1.2",
    "eslint-plugin-react": "7.1.0",
    "eslint-plugin-react-native": "3.0.1",
    "jest": "^24.8.0",
    "metro-react-native-babel-preset": "^0.56.0",
    "prettier": "1.5.3",
    "react-test-renderer": "16.8.6"
  },
  "jest": {
    "preset": "react-native"
  }
}

0x2 添加 Redux 支持

这里大概讲解下安装类库支持：

yarn add yarn add react-navigation react-native-gesture-handler react-native-reanimated native-base

链接字体库资源：

react-native link

react-navigation 在 Android 环境额外添加代码支持，具体情况文档： MainActivity.java

react-navigation 在 react-native 版本大于 0.60 的时候不需要执行 react-native link 链接。

由于项目需要状态管理支持，故添加 Redux 状态管理类库支持，在 React Native 环境下和 React 项目一样：

yarn add redux react-redux redux-logger

redux-logger 是监控状态数据流日志，可以在控制台输出状态值的信息。

由于项目基本环境是 Native Base 环境，这里怎么安装它就不再描述了，故在基础项目下添加项目支持 Redux 即可。打开 ./src/App.js 添加 Redux 能力支持：

import {Root} from "native-base";
import {createStackNavigator, createAppContainer} from "react-navigation";
import {applyMiddleware, createStore} from "redux";
import {Provider} from "react-redux";
import React from "react";
import logger from "redux-logger";
import allReducers from "./store";
import reduxDemo from "./screens/reduxDemo";
 
const store = createStore(
  allReducers,
  applyMiddleware(logger)
); // 创建 Store
 
const AppNavigator = createStackNavigator(
  {
    ReduxDemo: {screen: reduxDemo},
  },
  {
    initialRouteName: "ReduxDemo", // 路由入口
    headerMode: "none", // 由于 react-navigation 默认导航栏自定义效果很差，故隐藏
  },
);
 
const AppContainer = createAppContainer(AppNavigator);
 
export default () => (
  <Provider store={store}>
    <Root>
      <AppContainer/>
    </Root>
  </Provider>
);

创建状态触发事件业务集 ./store/reducers/counter.js ：

let count = 0;
export default function (state = count, action) {
  switch (action.type) {
    case "Increment":
      count++;
      break;
    case "Decrement":
      count--;
      break;
  }
  return count;
}

这里是根据触时不同条件要执行的业务，例如数字的增加和减少。假如项目下有很多触发业务集合，我们需要把他们归纳一起，并且方便获取状态值获取，新建 ./src/store/index.js ：

import {combineReducers} from "redux";
import countReducer from "./reducers/counter";
 
const allReducers = combineReducers({
  count: countReducer,
});
export default allReducers;

然后需要有个动作器来触发上面的业务，新建 ./src/store/actions/counter.js ：

export function increment() {
  return {
    type: "Increment"
  };
}
 
export function decrement() {
  return {
    type: "Decrement"
  };
}

如果需要改动状态值只能从上面的函数进行触发，这是唯一入口。

下面就编写页面进行测试，新建 ./src/screens/reduxDemo/index.js ：

import React, {Component} from "react";
import {Container, Content, Text, Card, Header, Body, Button, Title, CardItem} from "native-base";
import {increment, decrement} from "../../store/actions/counter";
import {bindActionCreators} from "redux";
import {connect} from "react-redux";
 
class Counter extends Component {
  render() {
    console.log(this.props.count);
    return (
      <Container>
        <Header>
          <Body>
            <Title>Redux 计数器</Title>
          </Body>
        </Header>
        <Content padder>
          <Card>
            <CardItem>
              <Text>
                {this.props.count}
              </Text>
            </CardItem>
          </Card>
          <Text/>
          <Button block onPress={() => this.props.increment()}>
            <Text>增加</Text>
          </Button>
          <Text/>
          <Button block onPress={() => this.props.decrement()}>
            <Text>减少</Text>
          </Button>
        </Content>
      </Container>
    );
  }
}
 
function mapStateToProps(state) {
  return {
    count: state.count // 这里等效于 prop.state 不过redux1帮你封装好的
  };
}
 
function matchDispatchToProps(dispatch) {
  return bindActionCreators({increment: increment, decrement: decrement}, dispatch); // 绑定动作事件
}
 
export default connect(mapStateToProps, matchDispatchToProps)(Counter); // 连接Redux

总结

代码参考： RN-Demo

原文 https://iiong.com/react-native-adds-redux-support/

链接: https://www.fly63.com/article/detial/4813