Creating an Interactive “Rollover” Screen

Let’s make an interactive screen where the names of Beatles albums are listed down the left side. When the user rolls her mouse over the names, they change color and a graphic of the album cover is displayed on the right side of the screen. We’ll also include a track list from http://www.beatles.com . Album names that have been “rolled over” will be shown in a third color so that the user can tell which ones she has already completed. Finally, we will display a message when all of the rollovers have been completed. This is a pretty realistic interactive training screen and will introduce us to a number of important concepts.

ToolBook – OpenScript

I assembled the graphics as .png files and created fields along the left with the titles of the albums. The names of these fields are “album 1” through “album 5.” You might be wondering why I put a space between the base (album) and the number. Unlike some of the other environments, ToolBook allows this. The advantage comes when it is time to “parse” the number from the name. With OpenScript, we can use syntax like this: word 2 of name of target. The space between the base and the number is what separates word 1 from word 2. This keeps us from running into problems when we get to album 11. In environments that don’t allow spaces in object names, I’ll put an _ instead and use some kind of split method for the same reason. You will see that in later examples.

I imported the graphics as resources and gave them matching names. Finally, I went to beatles.com and grabbed the track listing for each album and put them in fields named “field 1” through “field 5.” I hid these fields as we are going to read their text (technically their richText so that we preserve any formatting) and show them in a common “display field.” I like this technique because it avoids the need to reposition all the fields if we show and hide them in turn. Our design is then that we’ll show the album cover in a button and set this display field to be the track listing in response to the mouseEnter event, which is what ToolBook calls a rollover.

We are now ready to do some programming. Let’s start with the mouseEnter script shown below. We put this script at the page level so that we can write one mouseEnter handler for all five album name fields.

to handle mouseEnter
	system lastFieldId
	system stack completedInteractionList
	system dword numInteractions
	local string tarName
	local string tarNum
	local field fieldId
	
	tarName = name of target
	
	if word 1 of tarName = "album"
		tarNum = word 2 of tarName
		fieldId = field "display field"
		richText of fieldId = richText of field ("field " & tarNum)
		normalGraphic of button "albumImage" = bitmap ("album " & tarNum)
		strokeColor of target = blue
		sysCursor = 19 -- pen
		if lastFieldId  null
			strokeColor of lastFieldId = 120,25.125,100 -- dark green
		end if
		lastFieldId = target
		-- check for completion
		if ASYM_ItemInList(tarNum, completedInteractionList) = False 
			push tarNum onto completedInteractionList
		end if
		if itemCount(completedInteractionList) >= numInteractions
			richText of fieldId = "COMPLETED: " & richText of fieldId
		end if
	end if
	forward
end mouseEnter

We have lots of good programming concepts to discuss in this script. The first is a global variable, which we might define as some data that needs to survive beyond the life of the current handler or function. In OpenScript, we declare a global variable with the word system in front of it. In most cases, we want to declare a type as well. We do this so that the environment will help us if we do something dumb like try to assign “Joe” to a variable that is supposed to be a number. So the line system dword numInteractions means a global variable of type dword (positive integer) of the name numInteractions. In the mouseEnter script, we need three global variables:

1. A reference to the “previous” field that we entered. To understand this, we need to think through the set of events. The user will move his mouse into “Rubber Soul.” At that point, we want to turn it blue. He then moves the mouse into “Help.” We then turn “Help” blue to denote that it is the current item. We want to turn “Rubber Soul” green to show that we have already visited it. To do that, we need to remember which field we were in last. That is why we have lastFieldId. We don’t declare a datatype in this case because OpenScript is flexible enough to make it a field reference when we are using it but then allow us to set it to null when entering the page. If we type the variable, ToolBook would give us an error when we try to set it to null.

2. In addition to knowing the most recent field that the user entered, we need to keep track of all the fields in order to determine when the user has completed all of them. There are a number of ways we could approach this, but one of the simplest is to have a comma-delimited list of completed interactions (1,3,5 for example). This is a stack data type that we store in the completedInteractionList variable. It again needs to be global since we need to build up this stack interaction by interaction.

3. Finally, we need to know how many interactions there are in order to figure out if we are finished. This doesn’t strictly need to be a global variable but we end up using this value in two different handlers (mouseEnter and enterPage). The advantage of a global variable here is that we only have to change the value once if we change the number of interactions.

After the global variables, we have three local variables. This means that they survive only until the end of the handler or function. The tarName variable allows us to avoid having to keep referring to name of target. Similarly, we end up grabbing the interaction number and putting it in the tarNum variable . Finally, we end up referring to our display field several times. It is a good practice to put this object reference in a variable, which we call fieldId. This is a bit more efficient for the program if it doesn’t need to keep “resolving” the object reference and gives us a little less code to write.

Let’s now look at the logic. We use an if statement to limit our logic only to targets that have as their first word “album.” We need to do this since every object on the page will generate the mouseEnter event. Next, we populate our tarNum variable with word 2 of the name (1, 2, etc.). We build our fieldId reference to the display field and then start on the cooler stuff. We set the richText property of the display field to the richText of the corresponding (hidden) field that holds the album information. We use richText instead of text since the former keeps all the formatting such as font size, bold, and italics. After that we set the normalGraphic property of our “albumImage” button to the corresponding bitmap resource. The “normal” comes from the different button states (invert, checked, etc.) that can each have a graphic associated with it. Notice how we use “dynamic object referencing” to move from the name of the object to the field or bitmap object itself. The next line sets the strokeColor (the color of the text) to blue. We then set the sysCursor property to one of its defined values, which corresponds to a graphic that looks like a pen. I like to change the cursor for a mouseEnter interaction as another visual clue to the user that something is happening.

We now use our lastFieldId global variable discussed above. We check to see if it is null (because it won’t be defined yet the first time). If not, we set its strokeColor to a dark green. Either way, we set this global variable to the target (e.g., the current field the user is in). That way, we’ll set this field to green during the next interaction.

Our last task is to check for completion. We previously defined the completedInteractionList global variable and explained our plan to use it as a comma-delimited list of the interactions the user has completed. One reason to choose this format is that OpenScript has excellent support for “stacks” like this. We first use the built-in

ASYM_ItemInList() method to check if the current tarNum is in our global variable. If not, we push it on the variable, which has the effect of adding both the value and the comma (once there are two or more entries). We then use another built-in method, itemCount, to see if the number of items in the list is greater than or equal to our numInteractions global variable. If so, we update our display field to show “COMPLETED: ” at the front. In a real e-Learning application, I would typically change the look of the “Next Page” button or show an animation, but we already have enough complexity in this example! We end by forwarding the mouseEnter message so that higher-level scripts can handle the message if desired.

That script had most of the heavy lifting. The listing below has the “initialization” and “cleanup” scripts.

to handle enterPage
	system lastFieldId
	system dword numInteractions
	system stack completedInteractionList
	
	numInteractions = 5
	
	step num from 1 to numInteractions
		strokeColor of field ("album " & num) = 20,30,100 -- dark orange
	end step
	text of field "display field" = ""
	clear normalGraphic of button "albumImage"
	lastFieldId = null
	completedInteractionList = ""
	forward
end enterPage

to handle mouseLeave
	local string tarName
	
	tarName = name of target
	
	if word 1 of tarName = "album"
		sysCursor = default
	end if
	forward
end mouseLeave

The way to look at the enterPage handler is that we want to initialize the page to our desired state. We need to set our global variables so they are defined at the top of the script. We initialize numInteractions and then use our first step loop (a For loop in other programming languages) to set the strokeColor of each of our fields to a dark orange. In a step loop, the variable (num) goes from the initial condition (1) to the final value (numInteractions). The code within the loop runs each time. Notice how many lines of code we save plus get more flexibility to change the number of interactions without adding code by building the name of the field (“album ” & num), letting OpenScript build a reference, and setting the color. From there, we clear our display field and “albumImage” button. Finally, we clear our lastFieldId and completedInteractionList variables. It is very important that we forward the enterPage message – lots of other things happen in ToolBook at higher levels in response to this message.

The mouseLeave handler is quite simple. We use the same logic as above to make sure we are only handling the event for our album name fields. If so, we set the sysCursor back to default.

We will cover this example for the ToolBook Actions Editor, Flash, JavaScript, and Silverlight/XAML in future blog posts.

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About Jeff Rhodes
Jeff Rhodes is the Chief Technical Officer and owner of Platte Canyon Multimedia Software Corporation, a leader in developing commercial software that Improves the Lives of Training Developers. He graduated at the top of his class at the Air Force Academy, where he earned a Bachelor of Science in Electrical Engineering. Jeff received a Masters degree in Economics from the London School of Economics, which he attended under a British Marshall Scholarship. Jeff is the author of "Programming for e-Learning Developers: ToolBook, Flash, JavaScript, & Silverlight" and "VBTrain.Net: Creating Computer and Web Based Training with Visual Basic .NET." He also co-wrote "The ToolBook Companion." He has had numerous articles on training development published and is a frequent presenter at conferences both in the U.S. and Europe. Jeff lives in Colorado Springs with his wife Sue and sons Derek and Michael.

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