I am trying to have a default checked checkbox on a component dialog when editing. Here are the properties on the field:
jcr:primaryType: widget
checked: tr
To set checkbox with a default value of checked and save the property as a Boolean property type in the JCR (rather than a String), use the following Classic UI settings:
Or use the following settings in the Granite Touch UI:
There's a detailed writeup and demo at http://www.nateyolles.com/blog/2015/11/aem-checkboxes-using-sling-post-servlet.