jQuery检查单选按钮索引始终返回零

Question

我在页面中有以下单选按钮具有引导程序和jquery-ui：

<input type="radio" name="activeSolution" value="48">
...
<input type="radio" name="activeSolution" value="50">
...
<input type="radio" name="activeSolution" value="10">

我试图从jQuery自动完成选择事件中获取已检查的单选按钮索引，如下所示：

....
select: function( event, ui ) {           
       active = $("input:radio[name='activeSolution']:checked").index();
       alert($("input[name='activeSolution']:checked").index());
       alert(active)
....

始终alert(active)返回0我所做的几乎就像this answer。

我还尝试将元素提供给index()，如下所示：

active = $("input:radio[name='activeSolution']");
   alert(active.index(active.find(":checked")));

但是，这会返回-1

编辑：添加jQuery ui的完整代码上下文：

<script>
$( function() {    

    $( "#solutions" ).autocomplete({
      source: function( request, response ) {
          console.log(request.term)
        $.ajax( {
          url: "/solution/autocomplete/"+request.term,
          dataType: "json",
         /* data: {
            term: request.term
          },*/
          success: function( data ) {
            response( data );
          }
        } );
      },
      minLength: 2,
      select: function( event, ui ) {
       /* log( "Selected: " + ui.item.label + " aka " + ui.item.value );*/

       active = $("input:radio[name='activeSolution']:checked").index();
       alert($("input[name='activeSolution']:checked").index());
       alert(active)

       //alert($("input.activeSolution:checked").index());
      /* active = $("input:radio[name='activeSolution']");
       alert(active.index(active.find(":checked")));
       alert(active)
       alert(active.index(active.find(':checked')))*/
        this.value = ui.item.label;
        console.log(this)
        li = '<li class="list-group-item">'+ui.item.label+'<input type="hidden" name="solutions[][]" value="'+ui.item.value+'"><button type="button" class="btn btn-xs btn-danger badge remove"><i class="glyphicon glyphicon-minus"></i></button></li>';
        notFound = true;
        $(".solutions-list li input[name='solutions["+this.title+"][]']").each(function(i){
            //alert($(this).val()+"\n"+ui.item.value)
            if ($(this).val() == ui.item.value){
                alert('{{__('This cause is already selected!')}}');
                notFound = false;
                return false;
            }

        });
        if (notFound) $("#solutions-list").prepend(li);
        return false;
      }
    } );
  } );
  </script>