jquery - 一旦掉落的元素数量达到一定限制，就避免掉落

Question

我正在使用 Jquery UI Draggable。我试图避免一旦接收该项目的 div 达到限制，项目就会被丢弃。正如您在下面看到的，这是我的代码。

 $( "#grid-list" ).droppable({
        over: function(event, ui) {
          count = 0;
          $("#grid-list").find("li").each(function () {
            count++;

            if(count > $("#grid-list").data("albumlist")){
              alert("limit reached");
            }
          });
        }
      });

JS fiddle 示例:http://jsfiddle.net/r1Lnxby9/

Answer 1

编辑、更新

尝试从 html 、 drag 中删除 ondragstart="drag(event)" 、 draggable="true" > 未出现在 js 处定义；在 .droppable() options 处设置 tolerance:"touch" ；将 $("> li", this).length 替换为 count 、 $("#grid-list").each() ； >= 对于 > 如果预期结果是 .droppable() 元素内的 1 元素最大值；在over事件

内调用 event.preventDefault()、 event.stopPropagation()

  $("#list-albuns, #grid-list").sortable({
    connectWith: ".connectedSortable"
  }).disableSelection();

  $("#grid-list").droppable({
    tolerance: "touch",
    over: function(event, ui) {
      if ($("> li", this).length >= $(this).data("albumlist")) {
        event.preventDefault();
        event.stopPropagation();
        alert("limit");
      }
    }
  });

ul li {
  display: inline-block;
  list-style: none;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js">
</script>
<script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.11.4/jquery-ui.min.js">
</script>

<ul id="list-albuns" class="connectedSortable ui-sortable">
  <li id="0" class="ui-sortable-handle">
    <input type="hidden" name="albumId[]" value="0">
    <img id="dragimg0" height="126" width="126" src="http://userserve-ak.last.fm/serve/126/51552793.png" alt="Appetite for Destruction">
  </li>
  <li id="2" class="ui-sortable-handle">
    <input type="hidden" name="albumId[]" value="2">
    <img id="dragimg2" height="126" width="126" src="http://userserve-ak.last.fm/serve/126/97176319.png" alt="Use Your Illusion II">
  </li>
  <li id="3" class="ui-sortable-handle">
    <input type="hidden" name="albumId[]" value="3">
    <img id="dragimg3" height="126" width="126" src="http://userserve-ak.last.fm/serve/126/89710469.png" alt="40 Seasons - The Best Of Skid Row">
  </li>
  <li id="5" class="ui-sortable-handle">
    <input type="hidden" name="albumId[]" value="5">
    <img id="dragimg5" height="126" width="126" src="http://userserve-ak.last.fm/serve/126/56005467.jpg" alt="Danger Danger">
  </li>
  <li id="6" class="ui-sortable-handle">
    <input type="hidden" name="albumId[]" value="6">
    <img id="dragimg6" height="126" width="126" src="http://userserve-ak.last.fm/serve/126/85595741.jpg" alt="Screw It [Italy Bonus Tracks]">
  </li>
  <li id="7" class="ui-sortable-handle">
    <input type="hidden" name="albumId[]" value="7">
    <img id="dragimg7" height="126" width="126" src="http://userserve-ak.last.fm/serve/126/90791541.jpg" alt="Detonator">
  </li>
</ul>Drop Here:
<ul id="grid-list" data-albumlist="1" class="connectedSortable" style="width:500px; height:200px;display:block; border:2px solid black;"></ul>

jsfiddle http://jsfiddle.net/r1Lnxby9/2/