There does not appear to be any way to check the value of a single on/off (boolean) checkbox in the data selector for the Rules module. If "field-MyField" = checked or "field-MyField" = 1, then do 'blah'. Can Rules do this? I must be missing something
There's a mix of correct and incorrect details here, so I will try to sort them out. This is for Rules on Drupal 7, and applies to working with a Boolean field.
To make a condition that checks a field's Boolean state (true/false, yes/no, checked/unchecked), first make sure that you can access the field in the data selector. As Bojan mentioned above, and as it mentioned on the admin page itself,
To make entity fields appear in the data selector, you may have to use the condition 'entity has field' (or 'content is of type').
The operator you want to choose is "equals".
For the "Data Value" field, you can input values in two modes, make sure you are using "direct input mode". You should then be able to check the checkbox that represents TRUE for that field.
Translated, what you are saying is, "Is this field equal to TRUE?" You can also negate it by leaving it unchecked or using the "negate" option below.
After many hours of trial and error, I ended up solving the problem. Do not ask me to explain this because it makes no sense to me. If anyone can explain, then that would be greatly appreciated!
I set a new condition using DATA COMPARISON. I then select the "node:field-MyField:0" (there are actually up to 4 of these - node:field-MyField:1,node:field-MyField:2, etc..). I then set the COMPARISON to EQUALS. Then at the 2nd data selector part, it no longer is a text input box data selector, but now appears as a checkbox dataselector. When I click that checkbox data selector, and hit save, now the rules module is working correctly.
bangs head on wall
In the updated (fixed?) version of Rules, to do this, add a Data Comparison condition, select the appropriate field in the data selector
node:field-to-check, then on the next step leave the comparison operator as
equals. In the Data value group, there will be a checkbox helpfully named "Data Value" Rules will compare against the value of the checkbox as submitted on this page.