将功能组件转换为类组件Reactjs

Question

好吧，我是React的新手，我偶然发现了一段用功能组件编写的代码，我想知道如何将其转换为类组件。

import React from 'react';
import Avatar from '@material-ui/core/Avatar';
import Button from '@material-ui/core/Button';
import CssBaseline from '@material-ui/core/CssBaseline';
import TextField from '@material-ui/core/TextField';
import FormControlLabel from '@material-ui/core/FormControlLabel';
import Checkbox from '@material-ui/core/Checkbox';
import Link from '@material-ui/core/Link';
import Paper from '@material-ui/core/Paper';
import Box from '@material-ui/core/Box';
import Grid from '@material-ui/core/Grid';
import LockOutlinedIcon from '@material-ui/icons/LockOutlined';
import Typography from '@material-ui/core/Typography';
import { makeStyles } from '@material-ui/core/styles';
function Copyright() {
return (
<Typography variant="body2" color="textSecondary" align="center">
{'Copyright © '}
<Link color="inherit" href="https://material-ui.com/">
Your Website
</Link>{' '}
{new Date().getFullYear()}
{'.'}
</Typography>
);
}
const useStyles = makeStyles((theme) => ({
root: {
height: '100vh',
},
image: {
backgroundImage: 'url(https://source.unsplash.com/random)',
backgroundRepeat: 'no-repeat',
backgroundColor:
theme.palette.type === 'light' ? theme.palette.grey[50] : theme.palette.grey[900],
backgroundSize: 'cover',
backgroundPosition: 'center',
},
paper: {
margin: theme.spacing(8, 4),
display: 'flex',
flexDirection: 'column',
alignItems: 'center',
},
avatar: {
margin: theme.spacing(1),
backgroundColor: theme.palette.secondary.main,
},
form: {
width: '100%', // Fix IE 11 issue.
marginTop: theme.spacing(1),
},
submit: {
margin: theme.spacing(3, 0, 2),
},
}));
export default function SignInSide() {
const classes = useStyles();
return (
<Grid container component="main" className={classes.root}>
<CssBaseline />
<Grid item xs={false} sm={4} md={7} className={classes.image} />
<Grid item xs={12} sm={8} md={5} component={Paper} elevation={6} square>
<div className={classes.paper}>
<Avatar className={classes.avatar}>
<LockOutlinedIcon />
</Avatar>
<Typography component="h1" variant="h5">
Sign in
</Typography>
<form className={classes.form} noValidate>
<TextField
variant="outlined"
margin="normal"
required
fullWidth
id="email"
label="Email Address"
name="email"
autoComplete="email"
autoFocus
/>
<TextField
variant="outlined"
margin="normal"
required
fullWidth
name="password"
label="Password"
type="password"
id="password"
autoComplete="current-password"
/>
<FormControlLabel
control={<Checkbox value="remember" color="primary" />}
label="Remember me"
/>
<Button
type="submit"
fullWidth
variant="contained"
color="primary"
className={classes.submit}
>
Sign In
</Button>
<Grid container>
<Grid item xs>
<Link href="#" variant="body2">
Forgot password?
</Link>
</Grid>
<Grid item>
<Link href="#" variant="body2">
{"Don't have an account? Sign Up"}
</Link>
</Grid>
</Grid>
<Box mt={5}>
<Copyright />
</Box>
</form>
</div>
</Grid>
</Grid>
);
}

Answer 1

没有太多的更改要做，类组件必须有render((方法，并扩展React.component，仅此而已。这是您在类中更改的第一个功能组件组件：

class Copyright extends React.Component() {
render() {
return (
<Typography variant="body2" color="textSecondary" align="center">
{'Copyright © '}
<Link color="inherit" href="https://material-ui.com/">
Your Website
</Link>{' '}
{new Date().getFullYear()}
{'.'}
</Typography>
);
}
}

然而，您应该使用带钩子的功能组件，我认为这更容易理解，并且可以避免不推荐使用的生命周期方法问题。