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Richyfp · Jun 7, 2001, 06:57 PM

(Sorry for the long post!...)

To 'introduce' myself to the Applescript language, I am writing a script that will create a web page based on answers to questions asked by the script.

In setting the background color, I would like the user to be able to select a color from a list presented to them.

<BLOCKQUOTE>code:<HR><pre>if the button_pressed is "Colour picker" then choose from list {"Red", "Green", "Blue", "Orange", "Yellow"} with prompt "Choose a colour:" default items {"Red"}[/code]

As shown above, displaying the list of color options is not a problem. However, once the user clicks on 'OK', they will be returned to a dialog box, defined by the following:

<BLOCKQUOTE>code:<HR><pre>display dialog "Enter a background colour (as a hexadecimal value):" default answer "FFFFFF" buttons {"Cancel", "Colour picker", "OK"}[/code]

My problem is copying the answer selected in the list into this dialog box so that the user can see that their choice has been recognised. A further problem is converting the items in the list into hexadecimal RGB values to display in the dialog box.

For example, in the first dialogue box, the user will be asked to enter a color value or pick from a list. Once the user has selected a colour from the list, I would like the script to display the color's equivalent hexadecimal RGB value in the original dialogue box. My questions are:

How do I place the value returned from a list (the "choose from list" command) into a dialogue box?
If the values displayed in the list are normal words, how do I get them to display their hexadecimal RGB values in the dialog box?

Thanks in advance for your help!

Paul Crawford · Jul 27, 2001, 05:03 PM

Hi Richyfp,

[1] The 'choose from list' command returns a value of varying type (e.g., a list, a string, or even a boolean), depending on the parameters supplied to the command and on whether the user clicks OK or Cancel. In your example, it would return a list containing a single string, viz., the chosen colour-name. To obtain the chosen colour-name, you could do something like this:-<BLOCKQUOTE>code:<HR><pre>set bColourPickWasCancelled to false

if (button_pressed is "Colour picker") then
set theChosenColourNameAsList to �
(choose from list {"Red", "Green", "Blue", "Orange", "Yellow"} �
with prompt "Choose a colour:" default items {"Red"})

if (theChosenColourNameAsList is false) then
-- The user pressed 'Cancel' in this sub-dialogue
set bColourPickWasCancelled to true
else
-- Extract the chosen colour
set theChosenColourName to (item 1 of theChosenColourNameAsList)
end
end[/code]

[2.A] To convert the returned colour string into a hexadecimal string, you could set up a hardcoded "table" that maps colour names to their hex equivalents. E.g., you could use a list of sublists where each sublist represents a key/value pair, as follows:-<BLOCKQUOTE>code:<HR><pre>property k_ColourTable:{{"Red", "FF0000"} �
, {"Green", "00FF00"} �
, {"Blue", "0000FF"} �
, {"Orange", "FF7F00"} �
, {"Yellow", "FFFF00"} �
}[/code][2.B] Then, it would just be a matter of looping through the list's sublists to find the matching key/value pair, something like this:-<BLOCKQUOTE>code:<HR><pre>set bFoundColourHexValue to false

repeat with thisColourEntryRef in k_ColourTable
set thisColourEntry to (contents of thisColourEntryRef)

if (theChosenColourName = (item 1 of thisColourEntry)) then
-- We found a match
set theChosenColourHexValue to (item 2 of thisColourEntry)
set bFoundColourHexValue to true
exit repeat
end
end[/code]

[3] Unfortunately, there's no direct way to keep the main dialogue on-screen after the user clicks the 'Colour picker' button; by that time, the original dialogue has already been dismissed. However, it is possble to achieve a very similar effect, by using a repeat loop to continuously re-display the main dialogue after the 'Colour picker' sub-dialogue has itself been dismissed. In other words, putting it all together, we could do something like this:-<BLOCKQUOTE>code:<HR><pre>-- < Colour "table" is copied in here from listing 2.A >
property k_ColourTable:{{"Red", "FF0000"} �
, {"Green", "00FF00"} �
, {"Blue", "0000FF"} �
, {"Orange", "FF7F00"} �
, {"Yellow", "FFFF00"} �
}

-- ------------------------------------------------------------------------------
on run
-- Initialisation
set bUserIsDone to false
set theChosenColourHexValue to "FFFFFF" -- Default assumption

-- Keep prompting for a colour hex-value, until the User dismisses the main dialogue
repeat until bUserIsDone
-- Display the main dialogue
set theReply to �
(display dialog ("Enter a background colour (as a hexadecimal value):") �
default answer theChosenColourHexValue buttons {"Cancel", "Colour picker", "OK"})

-- Process the User's desired action
set button_pressed to (button returned of theReply)

if (button_pressed is "Colour picker") then
-- < Code is copied in here from the listing 1 >
-- < This will obtain 'theChosenColourName' >

set bColourPickWasCancelled to false

set theChosenColourNameAsList to �
(choose from list {"Red", "Green", "Blue", "Orange", "Yellow"} �
with prompt "Choose a colour:" default items {"Red"})

if (theChosenColourNameAsList is false) then
-- The user pressed 'Cancel' in this sub-dialogue
set bColourPickWasCancelled to true
else
-- Extract the chosen colour
set theChosenColourName to (item 1 of theChosenColourNameAsList)
end

if ( not bColourPickWasCancelled ) -- A colour was indeed picked
-- Translate the chosen colour-name into its hex equivalent

-- < Code is copied in here from the listing 2.B >
-- < This sets 'theChosenColourName' for the next iteration >
set bFoundColourHexValue to false

repeat with thisColourEntryRef in k_ColourTable
set thisColourEntry to (contents of thisColourEntryRef)

if (theChosenColourName = (item 1 of thisColourEntry)) then
-- We found a match
set theChosenColourHexValue to (item 2 of thisColourEntry)
set bFoundColourHexValue to true
exit repeat
end
end

-- Ensure that we were able to translate
if (not bFoundColourHexValue) then
set theErrMsg to ("Sorry, unknown colour-name: " & theChosenColourName)
set theErrNum to 1000
error theErrMsg number theErrNum
end
end

else if (button_pressed is "OK") then
-- Indicate that we're done, so we can exit the loop
set bUserIsDone to true

else (* 'Cancel' button was pressed *)
-- Normally, this would automatically be signalled as error -128,
-- so we shouldn't even get here...
end

end -- // repeat until bUserIsDone

-- < At this point, the desired colour hex-value is in 'theChosenColourHexValue' >
-- < It should be validated now, in case it was typed directly >
-- < Then, we can do the rest of the script >
-- [ ... ]

return
end[/code]

Regards,

--Paul