（2）React的开发
2024-10-20 21:12:17
实例：
import React from 'react';
class TodoList extends React.Component {
constructor(props){
super(props);
this.state = {
list: [
'learn react',
'learn english',
'learn vue'
]
}
}
handleBtnClick() {
this.setState({
list: [...this.state.list, 'hello world']
})
this.state.list.push('hello world');
}
render() {
return (
<div>
<div>
<input/>
<button onClick={this.handleBtnClick.bind(this)}>add</button>
</div>
<ul>
{
this.state.list.map((item) => {
return <li>{item}</li>
})
}
</ul>
</div>
);
}
}
export default TodoList;
新增列表 项功能
import React from 'react';
class TodoList extends React.Component {
constructor(props){
super(props);
this.state = {
list: [
],
inputValue: ''
}
}
handleBtnClick() {
this.setState({
list: [...this.state.list, this.state.inputValue],
inputValue: ''
})
}
handleInputChange(e) {
this.setState({
inputValue: e.target.value
})
}
render() {
return (
<div>
<div>
<input value={this.state.inputValue} onChange={this.handleInputChange.bind(this)}/>
<button onClick={this.handleBtnClick.bind(this)}>add</button>
</div>
<ul>
{
this.state.list.map((item) => {
return <li>{item}</li>
})
}
</ul>
</div>
);
}
}
export default TodoList;
删除：
import React from 'react';
class TodoList extends React.Component {
constructor(props){
super(props);
this.state = {
list: [
],
inputValue: ''
}
}
handleBtnClick() {
this.setState({
list: [...this.state.list, this.state.inputValue],
inputValue: ''
})
}
handleInputChange(e) {
this.setState({
inputValue: e.target.value
})
}
handleItemClick(index) {
const list = [...this.state.list];
list.splice(index, 1);
this.setState({
list: list
})
}
render() {
return (
<div>
<div>
<input value={this.state.inputValue} onChange={this.handleInputChange.bind(this)}/>
<button onClick={this.handleBtnClick.bind(this)}>add</button>
</div>
<ul>
{
this.state.list.map((item, index) => {
return <li key={index} onClick={this.handleItemClick.bind(this, index)}>{item}</li>
})
}
</ul>
</div>
);
}
}
export default TodoList;
React中组件
import React from 'react';
import TodoItem from './TodoItem'
class TodoList extends React.Component {
constructor(props){
super(props);
this.state = {
list: [
],
inputValue: ''
}
}
handleBtnClick() {
this.setState({
list: [...this.state.list, this.state.inputValue],
inputValue: ''
})
}
handleInputChange(e) {
this.setState({
inputValue: e.target.value
})
}
handleItemClick(index) {
const list = [...this.state.list];
list.splice(index, 1);
this.setState({
list: list
})
}
render() {
return (
<div>
<div>
<input value={this.state.inputValue} onChange={this.handleInputChange.bind(this)}/>
<button onClick={this.handleBtnClick.bind(this)}>add</button>
</div>
<ul>
{
this.state.list.map((item, index) => {
return <TodoItem key={index} content={item}/>
})
}
</ul>
</div>
);
}
}
export default TodoList;
import React from 'react';
class TodoItem extends React.Component {
render() {
return (
<div>{this.props.content}</div>
)
}
}
export default TodoItem;
import React from 'react';
import TodoItem from './TodoItem'
class TodoList extends React.Component {
constructor(props){
super(props);
this.state = {
list: [
],
inputValue: ''
}
}
handleBtnClick() {
this.setState({
list: [...this.state.list, this.state.inputValue],
inputValue: ''
})
}
handleInputChange(e) {
this.setState({
inputValue: e.target.value
})
}
// handleItemClick(index) {
// const list = [...this.state.list];
// list.splice(index, 1);
// this.setState({
// list: list
// })
// }
handleDelete(index) {
const list = [...this.state.list];
list.splice(index, 1);
this.setState({
list: list
})
}
render() {
return (
<div>
<div>
<input value={this.state.inputValue} onChange={this.handleInputChange.bind(this)}/>
<button onClick={this.handleBtnClick.bind(this)}>add</button>
</div>
<ul>
{
this.state.list.map((item, index) => {
return <TodoItem delete={this.handleDelete.bind(this)} key={index} content={item} index={index}/>
})
}
</ul>
</div>
);
}
}
export default TodoList;
代码优化：
import React from 'react';
import TodoItem from './TodoItem'
class TodoList extends React.Component {
constructor(props){
super(props);
this.state = {
list: [],
inputValue: ''
}
this.handleInputChange = this.handleInputChange.bind(this);
this.handleBtnClick = this.handleBtnClick.bind(this);
this.handleDelete = this.handleDelete.bind(this);
}
handleBtnClick() {
this.setState({
list: [...this.state.list, this.state.inputValue],
inputValue: ''
})
}
handleInputChange(e) {
this.setState({
inputValue: e.target.value
})
}
// handleItemClick(index) {
// const list = [...this.state.list];
// list.splice(index, 1);
// this.setState({
// list: list
// })
// }
handleDelete(index) {
const list = [...this.state.list];
list.splice(index, 1);
this.setState({
list: list
})
}
getTodoItems() {
return (
this.state.list.map((item, index) => {
return (
<TodoItem
delete={this.handleDelete}
key={index}
content={item}
index={index}
/>
)
})
)
}
render() {
return (
<div>
<div>
<input value={this.state.inputValue} onChange={this.handleInputChange}/>
<button onClick={this.handleBtnClick}>add</button>
</div>
<ul>{this.getTodoItems()}</ul>
</div>
);
}
}
export default TodoList;
import React from 'react';
class TodoItem extends React.Component {
// 子组件如果想和父组件通信，子组件要调用父组件传递过来的方法
constructor(props) {
super(props);
this.handleDelete = this.handleDelete.bind(this);
}
handleDelete() {
// const { delete, index } = this.props;
// delete(index);
this.props.delete(this.props.index);
console.log(this.props.index)
}
render() {
const { content } = this.props;
return (
<div onClick={this.handleDelete}>{this.props.content}</div>
)
}
}
export default TodoItem;
写css
import React from 'react';
import TodoItem from './TodoItem'
class TodoList extends React.Component {
constructor(props){
super(props);
this.state = {
list: [],
inputValue: ''
}
this.handleInputChange = this.handleInputChange.bind(this);
this.handleBtnClick = this.handleBtnClick.bind(this);
this.handleDelete = this.handleDelete.bind(this);
}
handleBtnClick() {
this.setState({
list: [...this.state.list, this.state.inputValue],
inputValue: ''
})
}
handleInputChange(e) {
this.setState({
inputValue: e.target.value
})
}
// handleItemClick(index) {
// const list = [...this.state.list];
// list.splice(index, 1);
// this.setState({
// list: list
// })
// }
handleDelete(index) {
const list = [...this.state.list];
list.splice(index, 1);
this.setState({
list: list
})
}
getTodoItems() {
return (
this.state.list.map((item, index) => {
return (
<TodoItem
delete={this.handleDelete}
key={index}
content={item}
index={index}
/>
)
})
)
}
render() {
return (
<div>
<div>
<input value={this.state.inputValue} onChange={this.handleInputChange}/>
<button className='red-btn' style={{background: 'red', color: '#fff'}} onClick={this.handleBtnClick}>add</button>
</div>
<ul>{this.getTodoItems()}</ul>
</div>
);
}
}
export default TodoList;
有两层：
import React from 'react';
import TodoItem from './TodoItem'
class TodoList extends React.Component {
constructor(props){
super(props);
this.state = {
list: [],
inputValue: ''
}
this.handleInputChange = this.handleInputChange.bind(this);
this.handleBtnClick = this.handleBtnClick.bind(this);
this.handleDelete = this.handleDelete.bind(this);
}
handleBtnClick() {
this.setState({
list: [...this.state.list, this.state.inputValue],
inputValue: ''
})
}
handleInputChange(e) {
this.setState({
inputValue: e.target.value
})
}
// handleItemClick(index) {
// const list = [...this.state.list];
// list.splice(index, 1);
// this.setState({
// list: list
// })
// }
handleDelete(index) {
const list = [...this.state.list];
list.splice(index, 1);
this.setState({
list: list
})
}
getTodoItems() {
return (
this.state.list.map((item, index) => {
return (
<TodoItem
delete={this.handleDelete}
key={index}
content={item}
index={index}
/>
)
})
)
}
render() {
return (
<React.Fragment>
<div>
<input value={this.state.inputValue} onChange={this.handleInputChange}/>
<button className='red-btn' onClick={this.handleBtnClick}>add</button>
</div>
<ul>{this.getTodoItems()}</ul>
</React.Fragment>
);
}
}
export default TodoList;
import React,{Component} from 'react';
class TodoItem extends Component {
// 子组件如果想和父组件通信，子组件要调用父组件传递过来的方法
constructor(props) {
super(props);
this.handleDelete = this.handleDelete.bind(this);
}
handleDelete() {
// const { delete, index } = this.props;
// delete(index);
this.props.delete(this.props.index);
console.log(this.props.index)
}
render() {
const { content } = this.props;
return (
<div onClick={this.handleDelete}>{this.props.content}</div>
)
}
}
export default TodoItem;
import React, { Component, Fragment } from 'react';
import TodoItem from './TodoItem'
class TodoList extends Component {
constructor(props){
super(props);
this.state = {
list: [],
inputValue: ''
}
this.handleInputChange = this.handleInputChange.bind(this);
this.handleBtnClick = this.handleBtnClick.bind(this);
this.handleDelete = this.handleDelete.bind(this);
}
handleBtnClick() {
this.setState({
list: [...this.state.list, this.state.inputValue],
inputValue: ''
})
}
handleInputChange(e) {
this.setState({
inputValue: e.target.value
})
}
// handleItemClick(index) {
// const list = [...this.state.list];
// list.splice(index, 1);
// this.setState({
// list: list
// })
// }
handleDelete(index) {
const list = [...this.state.list];
list.splice(index, 1);
this.setState({
list: list
})
}
getTodoItems() {
return (
this.state.list.map((item, index) => {
return (
<TodoItem
delete={this.handleDelete}
key={index}
content={item}
index={index}
/>
)
})
)
}
render() {
return (
<Fragment>
<div>
<input value={this.state.inputValue} onChange={this.handleInputChange}/>
<button className='red-btn' onClick={this.handleBtnClick}>add</button>
</div>
<ul>{this.getTodoItems()}</ul>
</Fragment>
);
}
}
export default TodoList;
.red-btn {
background: red;
color: #fff;
}
import React from 'react';
import ReactDOM from 'react-dom';
import TodoList from './TodoList';
import './style.css'
ReactDOM.render(<TodoList />, document.getElementById('root'));
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