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How to use React practice Tree component

小云云
Release: 2018-01-27 14:39:11
Original
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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',
     }
    ]
   }
 ]
}
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Reference code:


<p>
  <Tree 
    treeList = {node}
  /> 
</p>
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Component implementation code:


import React, { Component } from &#39;react&#39;;
import classNames from &#39;classnames&#39;;
const history = createHistory();
import {
  BrowserRouter as Router,
  HashRouter,
  Route,
  Link,
  Switch,
  NavLink
 } from &#39;react-router-dom&#39;;

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 === &#39;none&#39; ? &#39;block&#39; : &#39;none&#39; 
      }
    }
  }
  
  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;
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Rendering:

##DOM structure diagram

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

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