forms - Is it a good/acceptable practice to combine checkboxes with radio buttons for one question?

I work on a form, in which there are questions allowing either multiple choices or selecting just one. An example:

Which of the sweeties do you like:

• [ ] chocolate


• [ ] lollipops


• [ ] cookies


• ( ) none

In the above, [ ] represent checkboxes and ( ) represents radiobuttons. User can select multiple sweeties, but upon selecting "none" all the checkbox fields should be cleared, and vice versa: when "none" is selected, selecting any of the checkboxes should clear the radio in "none".

From UX perspective, is it ok to follow this way?

Edit:

Just to clarify: "None" does not mean "none of the above". Instead, it means that user does not like sweeties at all. In other words: the options included as checkboxes are just a subset of all possible sweeties. User can choose one/multiple of the sweeties or select "none". One conclusion is that the form does not cover a situation when user likes other sweeties than the ones listed as options, so definitely the form should also include "Other, please specify:" field as well.

Edit:

Ha! After 2 years I found it here:

So at least I am not alone in my belief that this is the right way to do it.

Answer

There should never be just one radio button, as it breaks the user's expectations on how they work. Radio buttons are meant to allow selection of one and only one item from a set of several radio buttons.

If you really want to use radio buttons, you could either go with this approach:

() I like the following sweeties:
  [] chocolate

  [] lollipops
  [] cookies
() I don't like sweeties.

Or you can change the "none" radio button to a "clear selections" button.