Add an itemTap
listener to your list. Then you can hide/show your div using its methods, or toggle a hiding CSS class like this:
{
xtype: 'list',
// ...
listeners: {
itemtap: function(list, index, target) {
var div = target.element.down('.extraInfo');
// avoid crashing for items with no extra info
if (div) {
div.toggleCls('x-hidden-display');
}
}
}
}