react实现拖拽模态框

import React from 'react';
import ReactDOM from 'react-dom';
import DragObj from './drag';

//main_class和title_class都是类名
export const DragHoc = (InnerComponent,main_class,title_class) =>
  class extends React.Component {
    componentDidMount() {
      this.init();
    }

    init = () => {
      setTimeout(() => {
        const child_node = ReactDOM.findDOMNode(this.refs.child); //获取到原生的dom元素
        if (child_node) {
          this.drag_obj = new DragObj(
            main_class?child_node.querySelector(`.${main_class}`):child_node, //只拖拽类名为 ${main_class} 的div
            title_class?child_node.querySelector(`.${title_class}`):child_node //当鼠标按在类名为 ${title_class} 的div上时才允许拖拽
          );
        }
      }, 0);
    };

    componentWillUnmount() {
      if (this.drag_obj) {
        this.drag_obj.destory();
      }
    }

    render() {
      return <InnerComponent {...this.props} ref="child" />;
    }
  };

export default class DragObj {
  start_x0 = 0;
  start_y0 = 0;
  start_x1 = 0;
  start_y1 = 0;
  state = false; //记录鼠标按键是否松开
  delta_x = 0; //相对于原始位置的横向偏移量
  delta_y = 0; //相对于原始位置的纵向偏移量

  constructor(target, move_item) {
    this.target = target; //被移动的dom元素
    this.move_item = move_item; //接受触发移动行为的dom元素,一般为模态框的头部
    this.init();
  }

  init() {
    this.move_item.style.cursor = 'move';
    this.bindEvent();
  }

  destory() {
    this.move_item.removeEventListener('mousedown', this.moveStartFun);
    document.removeEventListener('mousemove', this.movingFun);
    document.removeEventListener('mouseup', this.moveEndFun);
  }

  bindEvent() {
    this.moveStartFun = this.moveStart.bind(this);
    this.movingFun = this.moving.bind(this);
    this.moveEndFun = this.moveEnd.bind(this);
    this.move_item.addEventListener('mousedown', this.moveStartFun);
    document.addEventListener('mousemove', this.movingFun);
    document.addEventListener('mouseup', this.moveEndFun);
  }

  moveStart(e) {
    e.stopPropagation();
    this.state = true; //检测鼠标是否处于按下的状态
    this.start_x0 = e.pageX;
    this.start_y0 = e.pageY;
  }

  moving(e) {
    //鼠标移动时的默认操作
    e.stopPropagation();
    e.preventDefault();
    if (!this.state) {
      return false;
    }

    this.start_x1 = e.pageX;
    this.start_y1 = e.pageY;
    this.render();
  }

  moveEnd(e) {
    if (!this.state) {
      return false;
    }
    this.state = false;
    this.delta_x = this.start_x1 - this.start_x0 + this.delta_x;
    this.delta_y = this.start_y1 - this.start_y0 + this.delta_y;
  }

  render() {
    this.target.style.transform = `translate(${
      this.start_x1 - this.start_x0 + this.delta_x
    }px,${this.start_y1 - this.start_y0 + this.delta_y}px)`;
  }
}

import { DragHoc } from "./index.js";
import ToastExport from "../components/ToastExport/index.js";
//引入静态的模态框组件(用户自已定义的模态框组件)
const ToastExportv2 = DragHoc(ToastExport,"ant-modal-content","ant-modal-header"); 
//生成了具备拖拽功能的模态框组件

const { visible } = this.props;  //visible控制显示隐藏模态框
{visible?<ToastExportv2 visible={visible}/>:null}