在我的 App.js 代码中,我尝试绑定并捕获“handlesubmit”函数,然后附加到将填充的空列表。谢谢。
import React from 'react';
const App = () => {
const [songs, setSongs] = React.useState([]);
React.useEffect(() => {
const data = localStorage.getItem('songs');
if (!data) { }
setSongs(JSON.parse(data));
}, []);
React.useEffect(() => {
localStorage.setItem('songs', JSON.stringify(songs));
});
const handleSubmit = data => {
setSongs([data]);
}
return (
<main>
<h1>Music Editor</h1>
<form onSubmit={this.props.handleSubmit(this.handleSubmit.bind(this))} autoComplete="false">
<label for="title">Title:</label>
<input type="text" id="title" name="title" placeholder="Type title/name of song" value="" />
<input type="submit" value="Add song" />
</form>
</main>
);
}
export default App;
解释已在代码本身中注释。 这是 codesandbox 链接,可以查看该应用程序的工作情况。
import React from 'react';
const App = () => {
const [songs, setSongs] = React.useState([]);
// use another state for song title
const [songTitle, setSongTitle] = React.useState('');
React.useEffect(() => {
const data = localStorage.getItem('songs');
// only update the state when the data persists
if (data) setSongs(JSON.parse(data));
}, []);
// update the localStorage whenever the songs array changes
React.useEffect(() => {
localStorage.setItem('songs', JSON.stringify(songs));
}, [songs]);
// inside the functional component, there is no "this" keyword
const handleSubmit = (event) => {
event.preventDefault();
// append the new song title with the old one
setSongs([
...songs,
songTitle
]);
}
return (
<main>
<h1>Music Editor</h1>
<form onSubmit={handleSubmit} autoComplete="false">
<label htmlFor="title">Title:</label>
<input
type="text"
id="title"
name="title"
placeholder="Type title/name of song"
value={songTitle}
onChange={e => setSongTitle(e.target.value)}
/>
<input type="submit" value="Add song" />
</form>
</main>
);
}
export default App;
// heres example how you can handlesubmit in form using local storage
const handleSubmit = (e) => {
e.preventDefault();
// Simulate user login
const su = localStorage.getItem('user');
if (su) {
const user = JSON.parse(storedUser);
if (user.email === fd.email) {
setUser(user);
navigate('/profile');
} else {
setError('Invalid credentials');
}
} else {
setError('User not found');
}
};