How to use React practice Tree component

This article mainly introduces how to use the Tree component in React practice. The editor thinks it is quite good, so I will share it with you now and give it as a reference. Let’s follow the editor to take a look, I hope it can help everyone.

Implementing functions

• Rendering data

• Expand and merge

Use

Data structure:

const node = {
 title: '00000', 
 key: '0' ,
 level:'level1',
 open: true,
 child:[ 
   {
    title: '0-111111', 
    key: '0-0',
    level:'level2',
    open: true,
    child:[ 
      { 
       title: '0-1-1111', 
       key: '0-0-0',
       level:'level3',  
      }, 
      { 
       title: '0-1-2222', 
       key: '0-0-1',
       level:'level3',
       open: true,
       child: [
         { 
         title: '0-1-2-11111', 
         key: '0-0-1-0',
         level:'level4',
         open: true,
         child: [
           { 
           title: '0-1-2-1-111', 
           key: '0-0-1-0-0',
           level:'level5',
          }
         ]
        }
       ]
      },
      { 
       title: '0-1-33333', 
       key: '0-0-4',
       level:'level3',
      }, 
    ]
   },
   {
    title: '0-222222', 
    key: '0-2',
    level:'level2',
    open: false,
    child: [
     {
      title: '0-2-1111', 
      key: '0-2-0',
      level:'level3',
     },
     {
      title: '0-2-22222', 
      key: '0-2-1',
      level:'level3',
     },
     {
      title: '0-2-33333', 
      key: '0-2-2',
      level:'level3',
     }
    ]
   }
 ]
}

Reference code:

<p>
  <Tree 
    treeList = {node}
  /> 
</p>

Component implementation code:

import React, { Component } from 'react';
import classNames from 'classnames';
const history = createHistory();
import {
  BrowserRouter as Router,
  HashRouter,
  Route,
  Link,
  Switch,
  NavLink
 } from 'react-router-dom';

class Tree extends Component {

  constructor(props){
    super(props)
    this.treeItemCroup  = this.treeItemCroup.bind(this);
    this.handleClick   = this.handleClick.bind(this);

    this.state ={
      openList : false
    }
  }

  handleClick(e) {
    // 这是点击➡️ 时调用的方法
    // 如果当前这个➡️ 没有旋转，那就设置旋转，视觉效果
    e.target.style.transform = e.target.style.transform == "rotate(-90deg)" ? "rotate(0deg)" : "rotate(-90deg)"
    for(let item in e.target.parentNode.parentNode.childNodes){
      // 点击的时候设置当前层级的子元素素隐藏
      // 操作了DOM,我很难受
      if(item > 0){
        e.target.parentNode.parentNode.childNodes[item].style.display = e.target.parentNode.parentNode.childNodes[item].style.display === 'none' ? 'block' : 'none' 
      }
    }
  }
  
  itemTitle(item){
    // 这个是返回title，因为有时候是点击一个链接，所以设置了两种情况，如果node节点里面有component这个节点，那就设置成可以点击跳转
    if(item.component){ 
      return (<Link to={ item.component } >
             <span onClick={this.handleClick.bind(this)}>{item.title}</span>
          </Link>)
    }else{
      return (
         <span onClick={this.handleClick.bind(this)}>{item.title}</span>
      )
    }
  }

  treeItemCroup(itemGroup) {
    let itemGroupItem = []
    // 每个元素的样式，根据当前等级来设置样式，level1的就缩紧20px,level2的缩紧40px，一次类推，在视觉上呈现树的形式
    let itemStyle = {
        paddingLeft: 20*parseInt(itemGroup.level.slice(5), 10)+&#39;px&#39;
      }
    // 如果当前节点还有子元素，就设置一个➡️ 箭头 ，可以点击展开。
    let iconChevron = classNames(&#39;fa&#39;,{&#39;fa-chevron-down&#39; : itemGroup.child})
    // 把所有节点放在一个数组里面
    itemGroupItem.push(
      <ul>
        {/* 第一个层级 */}
        <li className={itemGroup.level} key={itemGroup.key} style={itemStyle}>
          <i aria-hidden="true" className={iconChevron} onClick={this.handleClick.bind(this)}></i>
          {this.itemTitle(itemGroup)}
        </li>
        {/* 调用tree方法 */}
        {this.tree(itemGroup.child)}
      </ul>
    )
    return itemGroupItem
  }

  tree(child){
    let treeItem
    // 如果有子元素
    if(child){ 
      // 子元素是数组的形式，把所有的子元素循环出来
      treeItem = child.map((item, key) => {
        // 同理，设置样式
        let itemStyle = {
          paddingLeft: 20*parseInt(item.level.slice(5), 10)+&#39;px&#39;
        }
        // 同理，设置➡️ 
        let iconChevron = classNames(&#39;fa&#39;,{&#39;fa-chevron-down&#39; : item.child})
        return (
          <ul>
            <li className={item.level} key={key} style={itemStyle}>
              <i aria-hidden="true" className={iconChevron} onClick={this.handleClick.bind(this)}></i>
              {this.itemTitle(item)}
            </li>
            {/* 如果当前子元素还有子元素，就递归使用tree方法，把当前子元素的子元素渲染出来 */}
            {this.tree(item.child)}
          </ul>
        )
      })
    }
    return treeItem
  }

  render() {
    return (
      <p className="tree">
        { this.treeItemCroup(this.props.treeList) }
      </p>
    );
  }
}

export default Tree;

Rendering:

##DOM structure diagram

I added some comments to the code, but it may still be difficult to understand the logic.

The above is the detailed content of How to use React practice Tree component. For more information, please follow other related articles on the PHP Chinese website!