xcode4 obtaining value of textbox - objective-c

Question

I am creating an applescript application in xcode 4 and am asking for some guidance. I have done a great deal of reading and scouring the internet but cannot find the answer I am looking for. I have a main window with a textbox and a button. I would like to be able to substitute hostname123 for the text in the textbox so that the command is: do shell script "sudo scutil --set HostName" & [Value of Textbox]. I have the button event set up so that the command will be executed on click. Can someone assist in obtaining the value of the textbox so that it can be used in the command?
on ButtonHandlerVolumeSetting0_(sender)
do shell script "sudo scutil --set HostName hostname123"
end ButtonHandlerVolumeSetting0_

Answer 1

First of all, I'm assuming this is in AppleScriptObjC, and not the older AppleScript Studio.
First, you need to make the AppleScript equivalent of an IBOutlet, which is an instance variable (or property) which references the text field and allows the Objective-C code (or AppleScript) to communicate with it. Toward the top of your AppleScript script, add a line like the following:
script MDAppDelegate
property parent : class "NSObject"
property hostNameTextField : missing value -- add this line
You'll then want to Control-drag from the instance of your script in the nib file to the text field in the window to "hook up" this outlet.
[UPDATE]: from the error message you're getting, it sounds like you haven't got this hostNameTextField connection set up properly in the nib file.
The MDAppDelegate blue cube icon in the nib file shown in the image below represents an instance of your AppleScript script that will be created at runtime when that nib file is loaded. You likely have already properly made the "connection" from your button to the blue AppleScript cube, which specifies that when you click the button, it should call the ButtonHandlerVolumeSetting0_() function (aka AppleScript handler). You now need to select your blue AppleScript cube instance like in the image below, and then right-click (or control-click) and drag from the blue cube to your input text field like I've shown.
When you let up on the mouse button, it should show a black popup panel with possible properties you can "hook up" to the text field. Select hostNameTextField.
Afterwards, when you select the blue AppleScript cube, in the Connections inspector in the right utility area, you can see the connections for the AppleScript script. Under Outlets, you'll see the hostNameTextField outlet and under Received Actions, you'll see ButtonHandlerVolumeSetting0_().
While the hostNameTextField property is set to an initial value of missing value in the AppleScript, (the AppleScript equivalent of Objective-C's nil), by making this connection in the nib file, at runtime, the value of hostNameTextField will be set to the NSTextField you specified. This will allow communication between the script and the object hierarchy that was archived into the nib file.
[END OF UPDATE]
An NSTextField inherits a method named stringValue from its superclass NSControl. This method returns the contents of the text field as an NSString (which equates to an AppleScript string). So inside the button click handler, you can get the string value as follows:
on ButtonHandlerVolumeSetting0_(sender)
set hostName to hostNameTextField's stringValue()
do shell script ("/usr/sbin/scutil --set HostName " & hostName) with administrator privileges
end ButtonHandlerVolumeSetting0_
When using do shell script, it's usually best to omit any inclusion of sudo from the script itself and to instead tack on the with administrator privileges qualifier. That signifies to AppleScript that you need to run the script with elevated privileges and it will handle showing the standard authentication dialog.