css - React 教程 - css 未加载
问题描述
我正在阅读位于此处的 React/Spring Boot 教程。一切进展顺利,包括 React 上组的初始显示。
然而,一旦 React 部分被重构以将组列表分成一个单独的模块并添加了一个导航栏,我得到一个没有任何 css 渲染的显示。
这是代码:
应用程序.js
import React, { Component } from 'react';
import './App.css';
import Home from './Home';
import { BrowserRouter as Router, Route, Switch } from 'react-router-dom';
import GroupList from './GroupList';
class App extends Component {
render() {
return (
<Router>
<Switch>
<Route path='/' exact={true} component={Home}/>
<Route path='/groups' exact={true} component={GroupList}/>
</Switch>
</Router>
)
}
}
export default App;
应用导航栏.js
import React, { Component } from 'react';
import { Collapse, Nav, Navbar, NavbarBrand, NavbarToggler, NavItem, NavLink } from 'reactstrap';
import { Link } from 'react-router-dom';
export default class AppNavbar extends Component {
constructor(props) {
super(props);
this.state = {isOpen: false};
this.toggle = this.toggle.bind(this);
}
toggle() {
this.setState({
isOpen: !this.state.isOpen
});
}
render() {
return <Navbar color="dark" dark expand="md">
<NavbarBrand tag={Link} to="/">Home</NavbarBrand>
<NavbarToggler onClick={this.toggle}/>
<Collapse isOpen={this.state.isOpen} navbar>
<Nav className="ml-auto" navbar>
<NavItem>
<NavLink
href="https://twitter.com/oktadev">@oktadev</NavLink>
</NavItem>
<NavItem>
<NavLink href="https://github.com/oktadeveloper/okta-spring-boot-react-crud-example">GitHub</NavLink>
</NavItem>
</Nav>
</Collapse>
</Navbar>;
}
}
主页.js
import './App.css';
import AppNavbar from './AppNavbar';
import { Link } from 'react-router-dom';
import { Button, Container } from 'reactstrap';
class Home extends Component {
render() {
return (
<div>
<AppNavbar/>
<Container fluid>
<Button color="link"><Link to="/groups">Manage JUG Tour</Link></Button>
</Container>
</div>
);
}
}
export default Home;
GroupList.js
import React, { Component } from 'react';
import { Button, ButtonGroup, Container, Table } from 'reactstrap';
import AppNavbar from './AppNavbar';
import { Link } from 'react-router-dom';
class GroupList extends Component {
constructor(props) {
super(props);
this.state = {groups: [], isLoading: true};
this.remove = this.remove.bind(this);
}
componentDidMount() {
this.setState({isLoading: true});
fetch('api/groups')
.then(response => response.json())
.then(data => this.setState({groups: data, isLoading: false}));
}
async remove(id) {
await fetch(`/api/group/${id}`, {
method: 'DELETE',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json'
}
}).then(() => {
let updatedGroups = [...this.state.groups].filter(i => i.id !== id);
this.setState({groups: updatedGroups});
});
}
render() {
const {groups, isLoading} = this.state;
if (isLoading) {
return <p>Loading...</p>;
}
const groupList = groups.map(group => {
const address = `${group.address || ''} ${group.city || ''} ${group.stateOrProvince || ''}`;
return <tr key={group.id}>
<td style={{whiteSpace: 'nowrap'}}>{group.name}</td>
<td>{address}</td>
<td>{group.events.map(event => {
return <div key={event.id}>{new Intl.DateTimeFormat('en-US', {
year: 'numeric',
month: 'long',
day: '2-digit'
}).format(new Date(event.date))}: {event.title}</div>
})}</td>
<td>
<ButtonGroup>
<Button size="sm" color="primary" tag={Link} to={"/groups/" + group.id}>Edit</Button>
<Button size="sm" color="danger" onClick={() => this.remove(group.id)}>Delete</Button>
</ButtonGroup>
</td>
</tr>
});
return (
<div>
<AppNavbar/>
<Container fluid>
<div className="float-right">
<Button color="success" tag={Link} to="/groups/new">Add Group</Button>
</div>
<h3>My JUG Tour</h3>
<Table className="mt-4">
<thead>
<tr>
<th width="20%">Name</th>
<th width="20%">Location</th>
<th>Events</th>
<th width="10%">Actions</th>
</tr>
</thead>
<tbody>
{groupList}
</tbody>
</Table>
</Container>
</div>
);
}
}
export default GroupList;
应用程序.css
.App {
text-align: center;
}
.container, .container-fluid {
margin-top: 20px;
}
.App-logo {
height: 40vmin;
pointer-events: none;
}
@media (prefers-reduced-motion: no-preference) {
.App-logo {
animation: App-logo-spin infinite 20s linear;
}
}
.App-header {
background-color: #282c34;
min-height: 100vh;
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
font-size: calc(10px + 2vmin);
color: white;
}
.App-link {
color: #61dafb;
}
@keyframes App-logo-spin {
from {
transform: rotate(0deg);
}
to {
transform: rotate(360deg);
}
}
非常感谢任何帮助。
解决方案
如果我理解正确,您没有使用您在App.css
文件中定义的类。
要使用样式,请将className
属性添加到需要样式的元素中。
例如,在您的home.js
:
<Button className="App-link" color="link"><Link to="/groups">Manage JUG Tour</Link></Button>
如App.js
您链接的示例中所示:
return (
<div className="App">
<header className="App-header">
<img src={logo} className="App-logo" alt="logo" />
<div className="App-intro">
<h2>JUG List</h2>
{groups.map(group =>
<div key={group.id}>
{group.name}
</div>
)}
</div>
</header>
</div>
);
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