dynamically enable/disable jquery sortable item

Question

I have table rows that are sortable depending on whether certain radio buttons are checked or not. The sortables are initialized on document.ready as follows:

$(document).ready(function() {
    // Return a helper with preserved width of cells
    // handy code I got from http://lanitdev.wordpress.com/2009/07/23/make-table-rows-sortable-using-jquery-ui-sortable/
    var fixHelper = function(e, ui) {
        ui.children().each(function() {
            $(this).width($(this).width());
        });
        return ui;
    };
    // #opts = table id; tr.ui-state-disabled class = rows not sortable
    $("#opts tbody").sortable({
        items: 'tr:not(.ui-state-disabled)',
        cursor: 'crosshair',
        helper: fixHelper
    }).disableSelection();
});

I have the following function attached to the radio buttons (ids prefixed "active_") onchange which either adds or removes the ui-state-disabled class attribute from table rows (dynamic ids prefixed "opt_"):

    var toggleDrag = function(i){
    if ($('#active_'+i+'-0').is(':checked')) {
        $('#opt_'+i).addClass('ui-state-disabled');
    }
    if ($('#active_'+i+'-1').is(':checked')) {
        $('#opt_'+i).removeClass();
    }
    $("#opts tbody").sortable("option", "items", "tr:not(.ui-state-disabled)");
    //$("#opts tbody").sortable("refresh");
    //alert($('#opt_'+i).attr('class')); - alert indicates that the class attribute is being changed
    //$("#opts tbody").sortable("option", "cursor", "auto"); - this works!
}

If I select a radio button that should make a previously un-sortable row sortable, it works and I can drag and drop the row. The problem is if I select a radio button to make a row that previously was sortable, un-sortable, I can still drag and drop it. The setter .sortable("option", "items", "tr:not..etc") doesn't appear "un-register" a row if it was previously sortable. I also tried .sortable("refresh") with no luck. And I have checked to see if the class attribute is being changed with an alert and it is.

Any help with this would be greatly appreciated.

Answer 1

I ran into the same problem, that the items option doesn't seem to remove items which had been previously enabled.

The cancel option, however, does. Note that the disabled items will shift around to make room for the sortable ones (the spot is still available as a drop target), but dragging the disabled items themselves will not work. Using a disabled class also makes it easy to change the style based on whether or not the item is sortable (see on jsfiddle).

The code here is partially based on Bah Bah the Lamb's answer, but it has been greatly tidied and simplified.

The html:

<ul id="sorted-list">
   <li>
       <p><input type="checkbox" checked="true" /> Item 1</p>
    </li>
   <li>
       <p class="disabled"><input type="checkbox" /> Item 2</p>
   </li>
   <li>
       <p><input type="checkbox" checked="true" /> Item 3</p>
   </li>
</ul>

The jQuery:

$("#sorted-list").sortable({
    cancel:".disabled"
});

// add or remove the 'disabled' class based on the value of the checkbox
$("#sorted-list input").click(function() {
    if (this.checked) {
        $(this.parentElement).removeClass("disabled");
    } else { 
        $(this.parentElement).addClass("disabled");
    }
});

The CSS:

li {
  border: 1px solid #aaa;
  background-color: #eee;
  color:#555;
  padding: 5px;
}

.disabled {
  color:#ddd;
}