This is how we use CocoaDialog (http://mstratman.github.io/cocoadialog/) in DeployStudio (http://deploystudio.com) workflows. CocoaDialog should be added to the scripts directory. This particular example will popup a choice and set the response in a variable. A later workflow item uses that variable in its logic to install the chosen package.

AskForPackage.sh

#!/bin/sh
#
# This script uses cocoaDialog to bring up a GUI dialog requesting which package to install. It will set a variable to be used later in the workflow.

# Set the 891 variable
P_891=""

# Path to the cocoaDialog tool
POPUP=`dirname "$0"`/cocoaDialog.app/Contents/MacOS/cocoaDialog

# Options for cocoaDialog
RUNMODE="standard-dropdown"
TITLE="Select your option:"
TEXT="Please select your required extra package from the list"
OTHEROPTS="--no-cancel --float --string-output"
ITEMS=( "None" "One" "Two" "Three" "Four" "Five" )
ICON="group"
ICONSIZE="128"

#Do the dialog, get the result and strip the Okay button code
RESPONSE=`$POPUP $RUNMODE $OTHEROPTS --icon $ICON --icon-size $ICONSIZE --title "${TITLE}" --text "${TEXT}" --items "${ITEMS[@]}"`
RESPONSE=`echo $RESPONSE | sed 's/Okay //g'`
#echo $RESPONSE

# Assign the variable to reflect the choice
case $RESPONSE in
    "None") # None
    	P_891=""
        ;;
    "One") 
    	P_891="PackageOne.pkg"
        ;;
    "Two") 
       	P_891="PackageTwo.pkg"
        ;;
    "Three") 
    	P_891="PackageThree.pkg"
        ;;
    "Four") 
    	P_891="PackageFour.pkg"
		;;    
    "Five") 
	P_891="PackageFive.pkg"
		;;
    *)
        echo "RuntimeAbortWorkflow: Unknown return value from popup: $retval"
        exit 1
        ;;
esac

# Write the 891 package info to the drive for later use
echo "RuntimeSetCustomProperty: P_891=${P_891}"
echo "${P_891}" > /tmp/P_891

exit 0