vue 拖拽元素指令

drag.js(指令js)

// 绑定事件
function _addEvent(el, eventName, fn){
  if(document.addEventListener){
    el.addEventListener(eventName, fn, false);
 }else if(window.attachEvent){
    el.attactEvent('on' + eventName, fn);
 }
};
// 解绑事件
function _offEvent(el, eventName, fn){
  if(document.removeEventListener){
    el.removeEventListener(eventName, fn, false);
 }else if(window.detachEvent){
    el.detachEvent('on' + eventName, fn);
 }
};
export default {
  bind(el, binding, vnode) {
    if(!binding.value.dragElSelector){
      console.error('需传递拖拽元素的选择器，参数名：dragElSelector')
      return;
 }
    if(binding.value.useDrag === false){
      return;
 }
    const dialogHeaderEl = el.querySelector(binding.value.dragElSelector);
 const dragDom = el;
 // 是否使用边界，如果使用边界则元素不会被拖出窗口
 const useBoundary = binding.value.useBoundary !== false;
 const onDrag = binding.value.onDrag;
 dialogHeaderEl.style.cssText += ';cursor:move;';
 // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
 const getStyle = (function() {
      if (window.document.currentStyle) {
        return (dom, attr) => dom.currentStyle[attr]
      } else {
        return (dom, attr) => getComputedStyle(dom, false)[attr]
      }
    })()
    let mouseDownEvent = (e) => {
      // console.log(e.clientX, e.clientY)
 // console.log(vnode); // 鼠标按下，计算当前元素距离可视区的距离
 const disX = e.clientX - dialogHeaderEl.offsetLeft
 const disY = e.clientY - dialogHeaderEl.offsetTop
 const dragDomWidth = dragDom.offsetWidth
 const dragDomHeight = dragDom.offsetHeight
 const screenWidth = document.body.clientWidth || window.innerWidth
 const screenHeight = document.body.clientHeight || window.innerHeight
 const minDragDomLeft = dragDom.offsetLeft
 const maxDragDomLeft = screenWidth - dragDom.offsetLeft - dragDomWidth
      const minDragDomTop = dragDom.offsetTop
 const maxDragDomTop = screenHeight - dragDom.offsetTop - dragDomHeight
      // console.log('minDragDomTop', minDragDomTop, maxDragDomTop)
 // console.log('screenHeight', screenHeight) // 获取到的值带px 正则匹配替换
 let styL = getStyle(dragDom, 'left')
      let styT = getStyle(dragDom, 'top')
      if (styL.includes('%')) {
        styL = +document.body.clientWidth * (+styL.replace(/%/g, '') / 100)
        styT = +document.body.clientHeight * (+styT.replace(/%/g, '') / 100)
      } else {
        styL = +styL.replace(/px/g, '')
        styT = +styT.replace(/px/g, '')
      }
    let mouseMoveEvent = (e) => {
      e.preventDefault();
 // 通过事件委托，计算移动的距离
 let left = e.clientX - disX
      let top = e.clientY - disY
      if(useBoundary){
        // 边界处理
 if (-(left) > minDragDomLeft) {
          left = -minDragDomLeft
        } else if (left > maxDragDomLeft) {
          left = maxDragDomLeft
        }
        // console.log('top maxDragDomTop', top, maxDragDomTop)
 if (-top > minDragDomTop) {
          top = -minDragDomTop
        }else if (top > maxDragDomTop) {
          top = maxDragDomTop
        }
      }
      // 移动当前元素
 dragDom.style.cssText += `;left:${left + styL}px;top:${top + styT}px;`
 // 执行 onDrag 事件
 if(typeof onDrag === 'function'){
        onDrag();
 }
    };
 _addEvent(document, 'mousemove', mouseMoveEvent);
 let mouseUpEvent = function () {
        _offEvent(document, 'mousemove', mouseMoveEvent);
 _offEvent(document, 'mouseup', mouseUpEvent);
 }
      _addEvent(document, 'mouseup', mouseUpEvent);
 };
 _addEvent(dialogHeaderEl, 'mousedown', mouseDownEvent);
 }
}

使用

<div  v-drag="{dragElSelector: '.simple-drag'}">
   <div >
      <h4 >简单拖拽</h4>
       <button type="button" >×</button>
   </div>
</div>

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