The AppleScript Studio Workshop

One thing you might want to do in an application is to set the cursor to be active in (to blink in) a text field of your choosing. This is done through the “first responder” property which can be set for windows in your application. I have had a lot of trouble with this. I haven’t had a lot of success in making something useful out of reading the property, even though you can set it. If you have a reference to your window in the variable “myWindow” then you could set the cursor to be active in a field called “secondField” with a line of code like this:

set the first responder of myWindow to text field "secondField" of myWindow

You can download a very simple sample application which shows you how you can respond to the “return” key to move to the next text field. It also has some code to show you a button that, when pressed, will move the first responder to the second field on the screen.

Download the sample XCode project here: First Responder Example

Here is are the key lines of code involved:

on clicked theObject
	if the name of theObject is "switchField" then
		set myWindow to the window of theObject
		set the first responder of myWindow ¬
           to text field "secondField" of myWindow
	end if
end clicked

on keyboard up theObject event theEvent
	set myWindow to the window of theObject
	if the name of theObject is "firstField" then
		if the character of theEvent is return then
			set the first responder of myWindow to ¬
                text field "secondField" of myWindow
		end if
	else if the name of theObject is "secondField" then
		if the character of theEvent is return then
			set the first responder of myWindow to ¬
                 text field "firstField" of myWindow
		end if
	end if
end keyboard up

Another simple but useful task when developing an application in AppleScript Studio is the ability to respond to keyboard input. For example, I want my application to respond to the “return” key, in certain fields, the same way that it does when one presses the “tab” key, ie. it moves the cursor to the next field.

Activate the “keyboard up” handler for the text field you wish to detect keyboard entries for and add some code.

When a key is pressed, a numerical Apple “key code” is generated that can be accessed by AppleScript. However, according to AppleScript Studio documentation:

KEY CODE: the hardware-dependent value of the key pressed; you aren’t likely to work with the key code and no constants are currently provided to specify key codes; however, you may want to experiment with possible values; (for example, for at least one keyboard, the key code for delete is 51 and for backspace is 117)

This is not very reassuring and I don’t know how standard the numbers are from keyboard to keyboard.

You can also access the “character” of the keyboard event which is just the literal character. Check the AppleScript document for other properties of the “event” class that may be useful to you, including booleans (true/false values) for things like: “command key down” “option key down” and “shift key down.”

Here is some code that will detect many of the possible keys typed into an input field and then show which numeric Apple key code corresponds to that key.

on keyboard up theObject event theEvent
	if the name of theObject is "inputField" then
		(* Is this the input field we are typing in?  *)
		set theKeyPressed to (key code of theEvent)
		(* Save the key code into a variable *)
		set theCharacterTyped to (character of theEvent)
		(* Save the character that was typed *)
		if theCharacterTyped is return then set theCharacterTyped to "RET"
		(* The return key doesn't show up nicely in the result, so let's
                replace it with "RET" *)
		
		if theKeyPressed is not 76 then
			(* 76 is the Apple key code for the "Enter" key 
                        - at least on my keyboard *)
			set the contents of text field "showResult" of window "sampleWindow" to ¬
				theCharacterTyped & "=" & theKeyPressed
			return false
			(* Returning false will allow the typing to continue without disruption *)
		else
			(* The "Enter" key was pressed *)
			display dialog "You pressed the enter key, I think."
			return false
		end if
	end if
end keyboard up

After checking to see if the user is typing into the input field (which they obviously are in a window that has only one text field receiving this handler), the key code and character of the event are put into a variable for later use (some will simply refer to this directly rather than putting it into a variable first). It then checks to see if the character typed is the return key and changes the variable to “RET” so it will show up easier in the output. The code then checks to see if the enter key was pressed (on my keyboard at least) and if not, displays the character pressed, an equals sign, and the corresponding key code. If it thinks the enter key was pressed (if your keyboard also has 76 set to “enter”) then it will display a dialog to that effect. Returning false allows the user to type undisturbed by the events. Set this to “true”, if you like, in order to see what happens to the typed text.

You can download the sample code to try this out here: Keyboard Input Sample

In the case of my own application, I’m looking for the user to press the “return” (key code 36 on my keyboard) or “enter” keys (key code 76) and if this is caught, I will “set the first responder” (see upcoming posting) to the next field I want the user to type into, as if they had pressed the “tab” key.

HAS, the devleoper of appscript left a useful comment in response to my earlier posting on the offset method. He offered an example of how one might easily and usefully call Cocoa methods to manipulate strings in AppleScript Studio that aren’t available directly in the AppleScript language.

If, for example, you wanted to use the existing Cocoa method to make a string all uppercase you could write code for a button that contains something like this:

on clicked theObject
	if the name of theObject is "makeUppercase" then
		set contents of text field "inputField" of window "myWindow" to call method "uppercaseString" of (contents of text field "inputField" of window "myWindow")
	end if
end clicked

If, instead, you wanted to have a string only capitalize the first letter of each word, then you would use the Cocoa function “capitalizedString” instead.

set contents of text field "inputField" of window "myWindow" to call method "capitalizedString" of (contents of text field "inputField" of window "myWindow")

You can download an example project with this example here: Call Method Example.

A full list of the Cocoa methods for the NSString class in Cocoa can be found in Apple document NSString Class Reference. Some of these methods need to be handled differently as they may require parameters etc. There is more detail on the call method command in the AppleScript Studio documentation to be found where you can learn more about how to include parameters.

Strings are only a simple beginning, this command opens up a lot of possibilities for using Cocoa methods that may not have equivalents in AppleScript, if done with care.

One of the first things I went poking around for on MacScripter forums was simply how to get a button to trigger a menu. I was looking for a simple “do menu item” kind of command. I don’t remember where I found it but this was apparently all I needed to do is activate the click handler for the button and assign it the correct script in Interface Builder and then add a script such as the one below:

on clicked theObject
    if the name of theObject is "doMenuItem" then
	   tell menu item "menuItemName" of menu "menuFile" of main menu to perform action
    end if
end clicked

More basics. After you create a menu and a menu item in Interface Builder, in the last tab of the inspector give it a name, select the applescript in your project where you will be adding the script for the menu item, and then give it an event handler by checking Menu: Choose Menu Item in the list of possible Event Handlers listed below.

on choose menu item theObject
	if the name of theObject is "myMenuItem" then
		display dialog "You chose my new menu item."
	end if
end choose menu item

This is pretty basic, but we all need to start somewhere. To change the contents of a text field (any NSTextField, including Labels), simple issue this kind of command:

set contents of text field "myTextField" of window "myWindow" to "Hello, World."

Make sure the “name” (not the “title”) of your target object (in this case “myTextField”) is correct in your NIB file in Interface Builder.