On / off checkbox with text box types are a little easier to set up than that.
For example, check the existing XF option
approveSharedBannedRejectedIp.
The main thing of note there would be the format parameters:
onoff makes the name of the checkbox as
enabled and
value makes the name of the text field as
days.
Then your array sub options (and your default value) would just be
enabled and
days so that you will access the option like this:
Code:
<xf:if is="$xf.options.yourOptionId.enabled">
{$xf.options.yourOptionId.days}
</xf:if>