ReactJS – 安装必要的模块

该应用程序使用下面给出的第三方反应库 –

Redux
React Redux
React Router
Formik
Redux Thunk（用于异步获取 api）

使用以下命令使用 npm 包管理器安装所有库 –

npm install --save redux react-redux react-router-dom formik redux-thunk

配置路由器

接下来，在src/components文件夹下创建一个新文件Home.js并编写一个基本的Home组件。

import React from "react";

class Home extends React.Component {
   render() {
      return (
         <div>
            <h1>Home</h1>
         </div>
      );
   }
}
export default Home;

接下来，在src/components文件夹下创建一个新文件ExpenseEntryItemForm.js并编写一个基本的ExpenseEntryItemForm组件。

import React from "react";

class ExpenseEntryItemForm extends React.Component {
   render() {
      return (
         <div>
            <h1>Expense list</h1>
         </div>
      );
   }
}
export default ExpenseEntryItemForm;

接下来，在src/components文件夹下创建一个新文件ExpenseEntryItemList.js并编写一个基本的ExpenseEntryItemList组件。

import React from "react";

class ExpenseEntryItemList extends React.Component {
   render() {
      return (
         <div>
            <h1>Expense form</h1>
         </div>
      );
   }
}
export default ExpenseEntryItemList;

在src/components文件夹下创建一个新文件App.css并为应用程序添加通用样式。

html {
   font-family: sans-serif;
}
a{
   text-decoration: none;
}
p, li, a{
   font-size: 14px;
}
nav ul {
   width: 100%;
   list-style-type: none;
   margin: 0;
   padding: 0;
   overflow: hidden;
   background-color: rgb(235,235,235);
}
nav li {
   float: left;
}
nav li a {
   display: block;
   color: black;
   text-align: center;
   padding: 14px 16px;
   text-decoration: none;
   font-size: 16px;
}
nav li a:hover {
   background-color: rgb(187, 202, 211);
}
input[type=text], input[type=number], input[type=date], select {
   width: 100%;
   padding: 12px 20px;
   margin: 8px 0;
   display: inline-block;
   border: 1px solid #ccc;
   border-radius: 4px;
   box-sizing: border-box;
}
input[type=submit] {
   width: 100%;
   background-color: #4CAF50;
   color: white;
   padding: 14px 20px;
   margin: 8px 0;
   border: none;
   border-radius: 4px;
   cursor: pointer;
}
input[type=submit]:hover {
   background-color: #45a049;
}
input:focus {
   border: 1px solid #d9d5e0;
}
#expenseForm div {
   border-radius: 5px;
   background-color: #f2f2f2;
   padding: 20px;
}
#expenseForm span {
   color: red;
}
html {
   font-family: sans-serif;
}
table {
   border-collapse: collapse;
   border: 2px solid rgb(200,200,200);
   letter-spacing: 1px;
   font-size: 0.8rem;
}
td, th {
   border: 1px solid rgb(190,190,190);
   padding: 10px 20px;
}
th {
   background-color: rgb(235,235,235);
}
td, th {
   text-align: left;
}
tr:nth-child(even) td {
   background-color: rgb(250,250,250);
}
tr:nth-child(odd) td {
   background-color: rgb(245,245,245);
}
caption {
   padding: 10px;
}
tr.highlight td { 
   background-color: #a6a8bd;
}

接下来，打开App.js并导入路由器依赖项。

import {
   BrowserRouter as Router,
   Link,
   Switch,
   Route
} from 'react-router-dom';

接下来，导入App.css。

import './App.css';

接下来，导入新创建的组件。

import Home from './Home'; 
import ExpenseEntryItemList from './ExpenseEntryItemList'; 
import ExpenseEntryItemForm from './ExpenseEntryItemForm';

接下来，在App组件中配置 Router。

class App extends React.Component {
   render() {
      return (
         <Router>
            <div>
               <nav>
                  <ul>
                     <li><Link to="/">Home</Link></li>
                     <li><Link to="/list">List Expenses</Link>lt;/li>
                     <li><Link to="/add">Add Expense</Link></li>
                  </ul>
               </nav>
               <Switch>
                  <Route path="/list">
                     <div style={   { padding: "10px 0px" }   }>
                        <ExpenseEntryItemList />
                     </div>
                  </Route>
                  <Route path="/add">
                     <div style={   { padding: "10px 0px" }   }>
                        <ExpenseEntryItemForm />
                     </div>
                  </Route>
                  <Route path="/">
                        <div>
                     <Home />
                     </div>
                  </Route>
               </Switch>
            </div>
         </Router>
      );
   }
}

App 组件的完整源代码如下 –

import React from "react";
import {
   BrowserRouter as Router,
   Link,
   Switch,
   Route
} from 'react-router-dom';

import './App.css';
import Home from './Home';
import ExpenseEntryItemList from './ExpenseEntryItemList';
import ExpenseEntryItemForm from './ExpenseEntryItemForm';

class App extends React.Component {
   render() {
      return (
         <Router>
            <div>
               <nav>
                  <ul>
                     <li><Link to="/">Home</Link></li>
                     <li><Link to="/list">List Expenses</Link></li>
                     <li><Link to="/add">Add Expense</Link></li>
                  </ul>
               </nav>

               <Switch>
                  <Route path="/list">
                     <div style={{ padding: "10px 0px" }}>
                        <ExpenseEntryItemList />
                     </div>
                  </Route>
                  <Route path="/add">
                     <div style={{ padding: "10px 0px" }}>
                        <ExpenseEntryItemForm />
                     </div>
                  </Route>
                  <Route path="/">
                     <div>
                        <Home />
                     </div>
                  </Route>
               </Switch>
            </div>
         </Router>
      );
   }
}
export default App;

接下来，使用 npm 命令为应用程序提供服务。

npm start

接下来，打开浏览器，在地址栏输入http://localhost:3000，回车。

配置路由器

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