vue添加全局自定义指令:拖拽

参考: https://segmentfault.com/a/1190000014572113
https://cn.vuejs.org/v2/guide/custom-directive.html

1.新建directives.js

import Vue from "vue";
Vue.directive("drag", {
    // 指令的定义
    bind: function(el) {
      let odiv = el; //获取当前元素
      odiv.style.position = 'fixed';
      odiv.onmousedown = (e) => {
        //算出鼠标相对元素的位置
        let disX = e.clientX - odiv.offsetLeft;
        let disY = e.clientY - odiv.offsetTop;
        document.onmousemove = (e) => {
          //用鼠标的位置减去鼠标相对元素的位置，得到元素的位置
          let left = e.clientX - disX;
          let top = e.clientY - disY;
          //移动当前元素
          odiv.style.left = left + "px";
          odiv.style.top = top + "px";
        };
        document.onmouseup = (e) => {
          document.onmousemove = null;
          document.onmouseup = null;
        };
      };
    },
});

2.在main.js引入

// main.js
import '**/directives.js'; 

3.在vue中使用