基于条件的jQuery可拖动还​​原 [英] jQuery draggable revert based on condition

问题描述

我遇到了一个与 jQuery 可拖放相关的问题.这是描述我想做的事情.

首先:我有两个 div.一个是

，另一个是 <div id="container">.container"有 10 个 <li> 可以拖放到selected"中.这是代码:

<div id="selected"><ul class="可排序列表"></ul></div><div id="容器"><ul class="可排序列表"><li>1</li><li>2</li><li>....</li><li>9</li><li>10</li></ul></div>

第二:我想允许任何 5 个 <li>s 从容器"到选定"div.如果有人试图添加第 6 个 <li>，那么它一定不允许用户添加它.即第 6 个 <li> 必须使用 jQuery 可拖动选项 revert.

即$("#container li").draggable({ revert: true });这是 javascript 代码.

$(document).ready(function(){变量总计 = 0;$("#selected").droppable({下降:函数(){总计 = $("#selected li").length;//警报(总计)；如果(总数> = 5){$("#container li").draggable({ revert: true });} 别的 {//下面的代码不工作$("#container li").draggable({ revert: false });//这让整个功能变得很奇怪.我可以拖动所有的<li>任何地方}}});});

这工作正常.

第三:但是当我将一个 <li> 从selected"拖到container"时，selected"div 将只有 4 个 <li>s.所以在这种情况下，稍后用户应该能够将另一个 <li> 从容器" div 添加到选定" div 中.但不幸的是，它不起作用.由于 if (total >= 5 ) 条件，我尝试拖放到已选择"中的所有 <li> 都将被还原.

谁能帮我解决这个问题，使用 draggable revert 选项?请...

解决方案

你可以使用accept 选项，它需要一个函数来更容易地做到这一点，像这样:

$("#selected ul").droppable({接受:函数(){return $("#selected li").length <5个；}});

你可以在这里测试一下.当您将元素拖出时，.length 会下降，它会再次接受元素...没有理由变得更复杂:)

I am having an issue related jQuery draggable and droppable. Here is description something what I want to do.

First: I have two divs. One is <div id="selected"> and another is <div id="container">. "container" has 10 <li> which are draggable and droppable into "selected". Here is code:

<div id="selected">
    <ul class="sortable-list">
    </ul>
</div>


<div id="container">
    <ul class="sortable-list">
             <li>1</li>
             <li>2</li>
             <li>....</li>
             <li>9</li>
             <li>10</li>
    </ul>
</div>

Second: I want to allow any 5 <li>s from "container" to "selected" div. If someone tries to add 6th <li>, then it must not allow user to it. That is the 6th <li> that is going to be inserted into "selected" must be reverted using jQuery draggable option revert.

i.e. $("#container li").draggable({ revert: true }); Here is javascript code for that.

$(document).ready(function(){

    var total = 0;
    $("#selected").droppable({
        drop: function() {
                total = $("#selected li").length;
                //alert(total);
                if (total >= 5) {
                    $("#container li").draggable({ revert: true });
                } else {
                            // below code is not working
                    $("#container li").draggable({ revert: false }); // this is making whole feature weird. I can drag all the <li> anywhere
                }
            }
    });
});

This is working fine.

Third: But when I drag an <li> from "selected" to "container", the "selected" div will have only 4 <li>s. So in this situation, later on user should be able to add another <li> into "selected" div from "container" div. But unfortunately it is not working. All the <li>s I try to drag and drop into "selected" are being reverted due to if (total >= 5 ) condition.

Can anyone help me to solve this out using draggable revert option? Please...

解决方案

You can use the accept option which takes a function to do this much easier, like this:

$("#selected ul").droppable({
    accept: function() {
        return $("#selected li").length < 5;
    }
});

You can test it out here. When you drag elements out, the .length goes down and it'll accept elements again...no reason to get any more complicated :)

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