Volume Number: 21 (2005)
Issue Number: 4
Column Tag: Programming

AppleScript Essentials

by Benjamin S. Waldie

Introduction To AppleScript Studio

In past articles, we have discussed many AppleScript-related topics. However, one of the topics that we have yet to touch on is AppleScript Studio, which is quickly becoming the tool of choice for AppleScript developers.

What Is AppleScript Studio

AppleScript Studio, contrary to what some of you may think, is not an application itself. Rather, it is the AppleScript development environment that is part of the Mac OS X developer tools.

The two main developer tools that AppleScript developers need to be concerned with in order to get started with AppleScript Studio are Interface Builder and Xcode. If you don't have these applications on your machine, you need to install the Mac OS X developer tools, which you should have gotten along with your Mac OS X system software.

Interface Builder, as the name implies, is what you may use to build interfaces for your scripts. Your interfaces may range from the very simple, to the extremely complex, depending on your programming skill, and the requirements of the task you want to automate. When building an interface in Interface Builder, you will have access to most of the standard interface elements that you see in Mac OS X, allowing you to design your interface with the look and feel of a regular application.

Xcode is the application in which you will write your AppleScript code, and link it to the objects in your interface. Xcode is not for the faint of heart. It is a real, live, professional development environment, and it has a learning curve. However, during this article, we will get started with some basics by creating a very simple AppleScript Studio application. Then, I'll make some suggestions for next steps in the learning process, and in future articles, we'll return to AppleScript Studio to discuss additional topics.

Building a Simple AppleScript Studio Application

For this initial project, we are going to build a fairly basic AppleScript Studio application, complete with an interface. This particular script will be used to select a random number that falls between two user-specified numbers.

Step 1 - Prepare Your Project

First, launch the Xcode application. Depending on whether or not you have launched Xcode before, you may see an initial dialog. Go ahead and dismiss any dialogs that may appear. Next, select New Project from the File menu, and you will be presented with a list of templates from which to choose. In the list, under Application, you will notice that there are a few types of templates with the word AppleScript in the name. In order to develop an AppleScript Studio application, you will want to select one of these. For this initial project, select AppleScript Application, and click the Next button.

The next interface will allow you to specify a name for your project, as well as a location. Enter the name Number Picker, specify a location, and click the Next button. At this time, Xcode will create your project in the specified location, and open the project in an interface window. Depending on the way your Xcode application has been configured, your window may look similar to figure 2.

An Xcode project contains a variety of components. However, at this initial stage, we are only going to be concerned about the following two:

Number Picker.applescript - This file, located under the Scripts folder in your project, is your main AppleScript file. Here, you will write the AppleScript code we will be linking to your interface.

MainMenu.nib - This file, located under the Resources folder in your project, is your interface file. This is where you will design your interface.

Step 2 - Design Your Interface

For this particular project, the next thing we are going to do is build our interface. To begin editing the project's interface, double click on the MainMenu.nib file in Xcode. This should automatically launch Interface Builder, and load the interface. If all goes well, you should see a MainMenu.nib window in Interface Builder, as well as a blank window titled Window. Click on the blank window.

Depending on the way your Interface Builder application is configured, you may or may not see an Info palette. To make this window visible, select Show Info from the Tools menu in the menu bar. If not already selected, choose Attributes from the popup menu at the top of the Info palette. Enter the text Number Picker into the Window Title field in the Info palette.

Now, it is time to begin adding some interface elements to the window. Depending on the way your Interface Builder application is configured, you may or may not see a palette of interface elements. If this palette is not visible, you can make it visible by selecting Show Palettes from the Tools > Show Palettes menu in the menu bar.

If you have never worked with Interface Builder before, you may want to browse through the various interface elements under each toolbar button in this palette. This should give you some idea of the types of interfaces you will be able to build in the future.

NOTE: Holding your mouse over a toolbar button in the interface elements palette will display a tool tip identifying the category of objects associated with the button. Likewise, holding your mouse over an interface object in the palette will display its name.

For this interface, we're going to add only a few basic elements to our Number Picker window. We'll start by adding two text fields. To do this, click on the Cocoa Text Controls button, and select and drag the NSTextField object from the upper left of the palette into your window. Do this again, and you should have two text fields on your window.

Next, select the NSTextField object labeled System Font Text, located in the lower right of the palette, and drag it twice into your window. Double click on each of these text fields that you have added to your window, and set their text to Starting Number and Ending Number.

Select the Cocoa Controls and Indicators button in the toolbar of the interface elements palette, select the NSButton object in the upper left corner of the palette, and drag it into your window. Double click on the button that has been added to the window, and change its name to Pick.

At this point, you may drag the various elements around the window until they are in the desired location. Notice as you drag elements around the window, that Interface Builder will display dashed lines suggesting proper placement of the objects, in relationship to other objects on the window. Try to arrange your interface similar to the one displayed in figure 6.

Step 3 - Add AppleScript Names to Inte face Objects

In order for the AppleScript code we are about to write to interact with the objects in our interface, we will first need to assign names to these objects. Sure, we could interact with objects by their index reference, such as text field 1 of window 1. However, when you start getting lots of interface elements, it becomes difficult to keep track of which objects are which. To assign a name to an object, first, select the object. Next, select AppleScript from the popup menu in the Info palette. You may then enter the desired name for the object into the Name field in the Info palette. For our interface, assign the name Main Window to the window. Next, assign the names Starting Number and Ending Number to the two empty text fields. Finally, assign the name Pick Number to the button in the window.

Step 4 - Link Interface Objects to AppleScript Code

Since we would like AppleScript code to trigger when we click the Pick button in our interface, we now need to link the button to our script. To do this, select the Pick button in the interface. Next, select AppleScript from the popup menu in the Info palette. You may have noticed already that when you have selected AppleScript from this popup menu, various event handlers appear below the Name field in the Info palette. These event handlers are actions that may be configured to cause the corresponding object to trigger specific AppleScript code. For example, for a button, the clicked event handler would cause the button to trigger AppleScript code whenever it is clicked by a user. Select the checkbox next to the clicked option.

Once you have selected the clicked event handler, you need to specify which AppleScript file to which the event handler will link. In this case, we only have one AppleScript file. However, for complex projects, we may have multiple files from which to choose. To specify our AppleScript file, select the checkbox next to Number Picker.applescript under Script at the bottom of the Info palette.

Step 5 - Adding AppleScript Code

Now that we have created our interface, and linked the interface elements to our AppleScript file, it is time to begin editing our AppleScript code. Since we have configured our interface to trigger code when a user clicks the Pick button, we are going to edit the code that will trigger when this action occurs. To get started, ensure that the Pick button is still selected, and click the Edit Script button at the bottom of the Info palette. This should bring Xcode back to the front, and display the Number Picker.applescript script. You should notice that the script already contains some initial AppleScript code.

The first thing that we need to do is get the values entered by the user into the Starting Number and Ending Number fields in our interface. Next, we are going to want to select a number in between those two numbers.

tell window "Main Window"
   set theStartingNumber to contents of text field "Starting Number"
   set theEndingNumber to contents of text field "Ending Number"
   set theNumberList to {}
   repeat with i from theStartingNumber to theEndingNumber
      set end of theNumberList to i
   end repeat
   display dialog "And the number is... " & some item of theNumberList
end tell

Add the above code to the on clicked theObject event handler in your script.

Step 6 - Building and Testing the Project

Now that we have added our AppleScript code, it's time to build and test our project. To do this, click the Build and Go button in the toolbar of your Xcode window. If all goes well, your application should build and launch. Test the application by entering a starting number and an ending number, and then click the Pick button.

Step 7 - Expand Your Application

Obviously, the example application we created during this article is very simple, to say the least. In a real-world solution, you would want to add much more functionality. For example, we did not add any kind of protection to ensure that a user actually enters a number into the Starting Number and Ending Number text fields. Right now, a user could enter text, and the solution would produce an error.

There are many other things you could do to make this solution more robust, and I encourage you to explore ways that you can expand and enhance it. I also invite you to download an application that I created and released as a freeware tool. My application, titled Ticket Picker, was the basis for this exercise. I created the application to distribute to Macintosh User Groups for use during raffles and drawings. You can download the application from the Freeware Products section of my website at http://www.automatedworkflows.com.

Next Steps

So, where do you go from here? Well, as I mentioned before, AppleScript Studio has a lot to learn. However, there are some good resources that can help you in your journey. For one, when you install the Mac OS X developer tools, Apple provides numerous AppleScript Studio examples. These examples are completely unlocked and fully editable, and I encourage you to explore them. They can be found in the Developer > Examples > AppleScript Studio folder. Additional example scripts can be found on the AppleScript website at http://www.apple.com/applescript/studio/.

Another good way to learn about AppleScript Studio is to look over the extensive documentation provided by Apple. For the most up to date documentation, visit http://developer.apple.com/documentation/AppleScript/.

I've said it before, and I'll say it again. One of the best resources for learning about AppleScript is the growing community of developers. If you are interested in learning AppleScript Studio, you should consider joining the AppleScript Studio Mailing List, hosted by Apple at http://lists.apple.com/mailman/listinfo/applescript-studio. The thousands of developers who currently subscribe to this list will no doubt be a valuable resource as you get started.

In Closing

As the title of this article indicates, this article is by no means meant to serve as a comprehensive tutorial on AppleScript Studio. It is simply meant to serve as an introduction, and to show how it is not too complicated to begin putting together your own applications with interfaces. Of course, creating more complex applications in AppleScript Studio requires some hard work and dedication. However, with a little practice, you will be on your way in no time. In future articles, we'll delve deeper into the AppleScript Studio world, and explore some more exciting things that you can do.

Until next time, keep scripting!

Benjamin Waldie is president of Automated Workflows, LLC, a firm specializing in AppleScript and workflow automation consulting. In addition to his role as a consultant, Benjamin is an evangelist of AppleScript, and can frequently be seen presenting at Macintosh User Groups, Seybold Seminars, and MacWorld. For additional information about Benjamin, please visit http://www.automatedworkflows.com, or email Benjamin at applescriptguru@mac.com.