Detailed explanation of JavaScript code to implement mouse drag and drop multi-selection function-JS Tutorial-php.cn

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Detailed explanation of JavaScript code to implement mouse drag and drop multi-selection function

巴扎黑

Aug 13, 2017 pm 02:50 PM

javascriptjscode

This article mainly introduces the example of implementing the mouse drag and drop multi-selection function in js. 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 and take a look.

Recently I made a function of using mouse drag and drop to multiple-select, so I sorted out my ideas and wrote a small demo:

The mask appears:

The block covered by the mask is the selected block (the background color is pink)

The following is the specific code, and the comments are in the text for communication with everyone.

<!DOCTYPE html>
<html>
<head>
  <title>鼠标拖拽多选功能</title>
  <script src="https://cdn.bootcss.com/jquery/1.10.2/jquery.min.js"></script>
  <style type="text/css">
    *{
      box-sizing:border-box;
    }
    ul{
      width:500px;
      height:auto;
      margin:0;
      padding:20px;
      font-size: 0;
      /*需设置定位*/
      position:relative;
    }
    li{
      width:70px;
      height:70px;
      margin:10px;
      padding:0;
      display:inline-block;
      vertical-align: top;
      font-size: 13px;
      border:1px solid #d9d9d9;
    }
    #moveSelected{
      position:absolute;
      background-color: blue;
      opacity:0.3;
      border:1px dashed #d9d9d9;
      top:0;
      left:0;
    }
    .selected{
      background-color: pink;
    }
  </style>
</head>
<body>
  <ul class="list">
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
    <li>6</li>
    <li>7</li>
    <li>8</li>
    <li>9</li>
    <li>10</li>
    <li>11</li>
    <li>12</li>
    <li>13</li>
    <li>14</li>
    <li>15</li>
    <li>16</li>
    <li>17</li>
    <li>18</li>
    <li>19</li>
    <li>20</li>
    <li>21</li>
    <li>22</li>
    <!-- 鼠标拖拽出的遮罩 （定位为 position:absolute）-->
    <!-- 遮罩最好是在绑定了mouseover事件的元素内部，并且不要阻止遮罩的冒泡事件。这样鼠标移到了遮罩上面，依然可以利用冒泡执行父元素的mouseover事件，就不会出现遮罩只能扩大，不能缩小的情况了（亲自试过） -->
    <p id="moveSelected"></p>
  </ul>
</body>
</html>
<script type="text/javascript">
  $(document).ready(function(){
    let moveSelected=$(&#39;#moveSelected&#39;)[0];
    let flag=false;//是搜开启拖拽的标志
    let oldLeft=0;//鼠标按下时的left,top
    let oldTop=0;
    let selectedList=[];//拖拽多选选中的块集合

    // 鼠标按下时开启拖拽多选，将遮罩定位并展现
    $(".list").mousedown(function(event) {
      flag=true;
      moveSelected.style.top=event.pageY+&#39;px&#39;;
      moveSelected.style.left=event.pageX+&#39;px&#39;;
      oldLeft=event.pageX;
      oldTop=event.pageY;
      event.preventDefault(); // 阻止默认行为
      event.stopPropagation(); // 阻止事件冒泡
    });
    // 鼠标移动时计算遮罩的位置，宽 高
    $(".list").mousemove(function(event) {
      if(!flag) return;//只有开启了拖拽，才进行mouseover操作
      if(event.pageX<oldLeft){//向左拖
        moveSelected.style.left=event.pageX+&#39;px&#39;;
        moveSelected.style.width=(oldLeft-event.pageX)+&#39;px&#39;;
      }else{
        moveSelected.style.width=(event.pageX-oldLeft)+&#39;px&#39;;
      }
      if(event.pageY<oldTop){//向上
        moveSelected.style.top=event.pageY+&#39;px&#39;;
        moveSelected.style.height=(oldTop-event.pageY)+&#39;px&#39;;
      }else{
        moveSelected.style.height=(event.pageY-oldTop)+&#39;px&#39;;
      }
      event.preventDefault(); // 阻止默认行为
      event.stopPropagation(); // 阻止事件冒泡
    });
    //鼠标抬起时计算遮罩的right 和 bottom，找出遮罩覆盖的块，关闭拖拽选中开关，清除遮罩数据
    $(".list").mouseup(function(event) {
      moveSelected.style.bottom=Number(moveSelected.style.top.split(&#39;px&#39;)[0])+Number(moveSelected.style.height.split(&#39;px&#39;)[0]) + &#39;px&#39;;
      moveSelected.style.right=Number(moveSelected.style.left.split(&#39;px&#39;)[0])+Number(moveSelected.style.width.split(&#39;px&#39;)[0])+&#39;px&#39;;
      findSelected();
      flag=false;
      clearDragData();
      event.preventDefault(); // 阻止默认行为
      event.stopPropagation(); // 阻止事件冒泡
    });
    $(".list").mouseleave(function(event) {
      flag=false;
      moveSelected.style.width=0;
      moveSelected.style.height=0;
      moveSelected.style.top=0;
      moveSelected.style.left=0;
      event.preventDefault(); // 阻止默认行为
      event.stopPropagation(); // 阻止事件冒泡
    });
    function findSelected(){
      let blockList=$(&#39;.list&#39;).find(&#39;li&#39;);
      for(let i=0;i<blockList.length;i++){
        //计算每个块的定位信息
        let left=$(blockList[i]).offset().left;
        let right=$(blockList[i]).width()+left;
        let top=$(blockList[i]).offset().top;
        let bottom=$(blockList[i]).height()+top;
        //判断每个块是否被遮罩盖住（即选中）
        let leftFlag=moveSelected.style.left.split(&#39;px&#39;)[0]<=left && left<=moveSelected.style.right.split(&#39;px&#39;)[0];
        let rightFlag=moveSelected.style.left.split(&#39;px&#39;)[0]<=right && right<=moveSelected.style.right.split(&#39;px&#39;)[0];
        let topFlag=moveSelected.style.top.split(&#39;px&#39;)[0]<=top && top<=moveSelected.style.bottom.split(&#39;px&#39;)[0];
        let bottomFlag=moveSelected.style.top.split(&#39;px&#39;)[0]<=bottom && bottom<=moveSelected.style.bottom.split(&#39;px&#39;)[0];
        if((leftFlag || rightFlag) && (topFlag || bottomFlag)){
          selectedList.push(blockList[i]);
          $(blockList[i]).addClass(&#39;selected&#39;);
        }
      }
      console.log(selectedList);
    }
    function clearDragData(){
      moveSelected.style.width=0;
      moveSelected.style.height=0;
      moveSelected.style.top=0;
      moveSelected.style.left=0;
      moveSelected.style.bottom=0;
      moveSelected.style.right=0;
    }
  });
</script>

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