Matrix & Radio Buttons - how to make radio button part of the same group?

Question

I'm creating a Matrix to allow users to upload images. One of the fields I want to put is a radio button for "Set as default image". That means each row in the Matrix will have a radio button.

Problem: there can only be one default image selected from the list of images. So, if one radio is selected, the other radio needs to be unselected. Is there a way to do this without using a JS solution?

Answer 1

There are two available fieldtypes specifically for this purpose. They both work great:

• MX Lone Star. It has the added advantage of working not only across rows, but across columns, too.
• Matrix Radio Group. By Pixel & Tonic. This one is not on Devot:ee and might only be
  described here.

Answer 2

I know this question has already been answered and even though my contribution serves a different purpose, this Q&A result was one of the first to display when I was searching for a solution for radio options within a Matrix cell type. I hope this will help anyone looking for a similar solution.

I found Field Pack (http://devot-ee.com/add-ons/field-pack) by Pixel & Tonic to be a great solution. It is fully compatible with Matrix.

After installing the Fieldtypes you want to use, select "Field Pack - Radio Buttons" as the Matrix Cell Type and then list the radio options on separate lines:

Then when creating the content, this is how the Radio options display:

The selected option will display exactly as you have entered it on the front-end: