Question

Example code here: http://jsfiddle.net/pDuxe/

I have a droppable space with two draggable elements. I have two issues:

1. If the droppable area already has a draggable item in it, if I then try and drop a second item on top, I need it to be refused and to revert back to its original position.

2. I can make use of the revert: 'invalid' code without problems, but if I place a draggable item into a droppable area and then want to move it back – it keeps reverting back to its place in the droppable area and not its original position.

So, how would I go about achieving those two situations?

Answer 1

What you can do is wrap your draggables in a div that you also make droppable:

<div id="originalposition">
    <div id="draggable" class="ui-widget-content">
        <p>Drag me to my target</p>
    </div>

    <div id="draggable2" class="ui-widget-content">
        <p>Drag me to my target</p>
    </div>
</div>

Then you can do something like the following:

$(function() {
    $("#draggable").draggable({ revert: 'invalid' });
    $("#draggable2").draggable({ revert: 'invalid' });
    $("#originalposition").droppable({
        drop: function(event,ui) {
                 $("#droppable").removeClass("ui-state-highlight").addClass("ui-widget-header").html("<p>Drop here</p>"); 
              }
    });
    $("#droppable").droppable({
        drop: function(event, ui) {
                 $(this).addClass("ui-state-highlight").find("p").html("Dropped!");
              },
        accept: function(dropElem) {
                //dropElem was the dropped element, return true or false to accept/refuse it
                return (!$(this).hasClass("ui-state-highlight") && $(dropElem).hasClass("ui-widget-content"));
                }
    });
});​

Fiddle here.