Android : Programatically change check box state in dialog box?

I have an alert dialog with a series of checkboxes. The first one is 'Select All'; the others are user options.

How can I programatically change the state of the checkboxes so that when 'Select All' is checked, all the others are also checked, and when one of the others is selected, 'Select All' is unchecked? I can set up the initial state in the configuration, but can't work out how to change the checked state of the boxes on the fly.

Thanks.