react中实现可拖动div

<draggable panelid="要拖动容器的id" titleid="容器内标题的id" contentid="容器内除标题外的其他部分id" setpanelposition={this.setpanelposition.bind(this)}/>

  //推拽回调函数
  setpanelposition(left,top){
    this.setstate({pagex: left, pagey: top})
  }

<div id="要拖动的id" style={{left:this.state.pagex,top:this.state.pagey}}></div>

import react from 'react';
class draggable extends react.component {
  constructor(props) {
    super(props);
    this.state = {
    };
  }
  //拖拽
  initdrag(){
    let {panelid,titleid,contentid} = this.props;
    this.paneldom = document.getelementbyid(panelid);
    this.titledom = document.getelementbyid(titleid);
    this.contentdom = document.getelementbyid(contentid);
    this.backgrounddom = document.body;
    this.bindevent();
  }

  //region event
  componentdidmount() {
    this.initdrag();
  }
  bindevent(){
    this.titledom.onmousedown = this.onmousedown.bind(this);
    this.titledom.onmouseup = this.onmouseup.bind(this);
    this.titledom.onmousemove = this.onmousemove.bind(this);

    this.contentdom.onmouseup = this.oncontentmouseup.bind(this);
    this.contentdom.onmousemove = this.oncontentmousemove.bind(this);

    this.backgrounddom.onmouseup = this.onbackgroundmouseup.bind(this);
    this.backgrounddom.onmousemove = this.onbackgroundmousemove.bind(this);
    let step = ()=>{
      this.activeanimation = true;
      window.requestanimationframe(step);
    };
    window.requestanimationframe(step);
  }

  /**
   * 鼠标按下，设置modal状态为可移动，并注册鼠标移动事件
   * 计算鼠标按下时，指针所在位置与modal位置以及两者的差值
   **/
  onmousedown (e) {
    const position = this.getposition(e)
    this.setstate({moving: true, diffx: position.diffx, diffy: position.diffy})
  }

  // 松开鼠标，设置modal状态为不可移动
  onmouseup (e) {
    const { moving } = this.state
    moving && this.setstate({moving: false});
  }

  // 鼠标移动重新设置modal的位置
  onmousemove (e) {
    const {moving, diffx, diffy} = this.state
    if (moving) {
      if(this.activeanimation){
        // 获取鼠标位置数据
        const position = this.getposition(e)
        // 计算modal应该随鼠标移动到的坐标
        const x = position.mousex - diffx
        const y = position.mousey - diffy
        // 窗口大小，结构限制，需要做调整，减去侧边栏宽度
        const { clientwidth, clientheight } = document.documentelement
        const modal = this.paneldom
        if (modal) {
          // 计算modal坐标的最大值
          const maxheight = clientheight - modal.offsetheight
          const maxwidth = clientwidth - modal.offsetwidth
          // 判断得出modal的最终位置，不得超出浏览器可见窗口
          const left = x > 0 ? (x < maxwidth ? x : maxwidth) : 0
          const top = y > 0 ? (y < maxheight ? y : maxheight) : 0
          if(this.props.setpanelposition){
            this.props.setpanelposition(left,top);
          }
        }
        this.activeanimation = false;
      }
    }
  }
  oncontentmousemove(e){
    let obj = {};
    obj.target = this.titledom;
    obj.pagex = e.pagex;
    obj.screeny = e.screeny;
    this.onmousemove(obj);
  }
  oncontentmouseup(){
    this.onmouseup();
  }
  onbackgroundmousemove(e){
    let obj = {};
    obj.target = this.titledom;
    obj.pagex = e.pagex;
    obj.screeny = e.screeny;
    this.onmousemove(obj);
  }
  onbackgroundmouseup(){
    this.onmouseup();
  }
  //endregion

  //region request
  // 获取鼠标点击title时的坐标、title的坐标以及两者的位移
  getposition (e) {
    // 标题dom元素titledom
    const titledom = e.target
    // titledom的坐标(视窗)
    const x = titledom.getboundingclientrect().left
    // 由于y轴出现滚动条，需要与鼠标保持一致，存储页面相对位置
    const y = this.paneldom.offsettop

    // 鼠标点击的坐标(页面)
    let mousex = e.pagex
    let mousey = e.screeny
    // 鼠标点击位置与modal的位移
    const diffx = mousex - x
    const diffy = mousey - y
    return {x, y, mousex, mousey, diffx, diffy}
  }
  //endregion

  //region render
  //endregion

  //region clear
  //endregion

  render() {
    return (
      <>
      </>
    );
  }
}
export default draggable;