Intro

In the previous blog post I introduced you to the common JS API, and you used the method 'setVariableValue' to populate a variable defined in the Captivate project. That value was a random number generated in the JS window, using the Math.random() and the Math.floor methods. The values were integers, between fixed numbers 10 (included) and 100 (not included). In this second article you'll learn to know a new method 'getVariableValue' from the JS API, which lets you transfer a value to JS. We started with the mathematical operation 'Sum', now we'll switch to 'Subtractions' needing again the command 'Expression'. Because CP cannot handle well negative values, we'll have to take care of that as well.

The progress bar introduced with the Sum exercises, will be continued. You'll see that it is possible to change the state of an object, displayed for the rest of the project, from a slide where that object is not inserted. 

Scenario Subtract Slide

Used objects

The same multistate objects are used as on the Sum slide (see state panels on previous post):

• Sticky figure with its states and a motion effect for the minus sign
• OK button, which changes to a New button after the first exercise
• Progress bar, which has been displayed for the rest of the project.

In this slide I only used TEB's, which I can control due to the presence of the CpExtra widget (InfoSemantics). The consequence is that this description is only valid for HTML output. For SWF output the TEB can be replaced by a Scrolling Text Interaction:

• TEB_max accepts only numbers and is empty when starting - associated variable is v_max
• TEB_min accepts only numbers and has a default value of 10 (changeable)  - associated variable is v_min
• TEB_result accepts only numbers - associated variable is v_result (reused from sum slide)

Two shape buttons, that are alternatively enabled/disabled:

• SB_Number is the OK/New button, triggers the advanced conditional action SubtractTerms
• SB_CheckSubtract is the Check button, triggers the advanced conditional action CheckSubtract

Variables

Some variables created for the Sum slide are reused:

• v_one, v_two, v_three, v_four: are reused for the values of the two terms, which will end up in v_one (first term) and v_two; those variables will be reset by the On Enter action of the Subtract slide

• v_result: will store the result value typed in by the user in TEB_result, has to be reset as well.

• v_check: will be calculated and used to validate the result given by the learner. 

• v_progress: is a counter for the correct answers, will be used to change the state of the progress bar; this variable is not reset but starts with the value 5 (end value after the Sum slide)

• v_null: empty variable used to clear the content of the displayed result for a new sum (see Where is Null?)

• xprefTEBUpdateFromVariable:  for HTML output, one of the CpExtra variables. When assigning the value 1 to this variable (with CpExtra widget loaded either in the file, or headless) it is possible to change the associated variable of a TEB by an action, and it will be reflected immediately in the TEB. I used this to clear TEB_Result.

New variables are:

• v_max associated with TEB_max will store the maximum value for the terms
  
  
• v_min associated with TEB_min will store the minimum value for the terms

Advanced Actions

Shared actions were not possible. One Standard advanced action was needed (to reset vars) and two Conditional actions.

EnterSubtract

This very simple standard action, triggered by the On Enter event of the slide, clears several variables that are reused from the Sum slide:

SubtractTerms

This conditional action is triggered by the OK/New button SB_Number. It has 3 decisions:

1. "CheckCorrect" will compare the values stored in v_max en v_min. If the maximum value is not exceeding the minimum value, the maximum value will be calculated by adding 200 to the minimum value.
   
   
2. "RandomNum" will generate two random numbers and store them in the variables v_three and v_four. Reason is that the last decision will have to put the largest number into v_one and  the smallest in v_two. This could have been checked in the JS script window as well, but I wanted to keep the JS as simple as possible and checked with the last decision. 
   
   
3. "CheckMax" compares the values in v_three and v_four. The largest value will be assigned to v_one, the other to v_two. This decision also calculates the result of the subtraction to be stored in the variable v_check (will be used to check the user's entry).
   
   

CheckSubtract

This conditional action is triggered by the check shape button SB_CheckSubtract and has 6 decisions

The first decision 'Checker', will check the entered value (v_result) with the correct value (v_check). It is the only decision with a Then and Else part. For correct answer, the state of the sticky character is changed, the counter (v_progress) is incremented,  the state of the button SB_Number is changed to another state and enabled again, while the button SB_CheckSubtract is disabled. For an incorrect answer, the counter is not incremented, and the sticky character is changed to another state.

The 5 other decisions 'ProgressXxxx' check the value of v_counter and show the appropriate state for the progress bar. The last decision 'ProgressTen' will also change the sticky Character to its state GoNext and enable the click box to proceed to the next slide (subject of the next blog post, with Multiply exercises).

Javascript 

In the previous post you learned to use 'window.cpAPIInterfaceSetVariable (x,y)' method to populate a variable x (to be entered as a string between quotes) with a value y. You calculated y by using a combination of two Math methods in JS: 

• Math.random() which generates a random number between 0 and 1 (not included)
• Math.floor() which will convert a decimal number to an integer by rounding it down (cutting off the decimals).

For the sum slide we used a combination of those two methods, to end up with a random number between 10 and 100 (not included):

Math.floor(Math.random()*(100-10)+10))

For the Subtraction, the maximum and minimum values are not fixed, but stored in Captivate variables v_max and v_min. Due to the first decision in SubtractTerms action, we are sure that v_max > v_min. Those value will be transferred to JS variables with the method 'window.cpAPIInterfaceGetVariable(x)' where 'x' is the name of the Captivate variable, entered as a string (between quotes). Example:

var max = window.cpAPIInterfaceGetVariable("v_max");       stores value of v_max in JS variable max

var first = Math.floor(Math.random()*(max-min)+min);

var second= Math.floor(Math.random()*(max-min)+min);

You are already familiar with SetVariableValue to store the result of first in v_three - Captivate variable, and second in v_four. 

window.cpAPIInterface.setVariableValue("v_three",first);
window.cpAPIInterface.setVariableValue("v_four",second);

Conclusion

You earned a second star, soon a third part will be ready, up to multiplications and bit more of randomness.

Intro

How to use Adobe Captivate to create a course for simple calculations, has been popping up on the forums several times. You can use Text Entry Boxes, MCQ's to reach that goal, but that is pretty limiting. Some examples can be found in this older blog post where the real goal was to have the score being linked to the attempts.

I started using JavaScript in Captivate projects since the release of the common API for JS (version 8) whenever the advanced actions did lack the wanted functionality. For those who want to start using JS, I wanted to explain some very simple use cases in a sequence of 4 articles that will focus on the 4 basic operators that are available in the Expression command: sum, subtract, multiply and divide. Each of the posts will introduce a JS example. The Expression command is not available as a simple command from the dropdown list in the Actions tab, it is only available in advanced/shared actions. 

This article will focus on the Sum operator, and introduce JS to make it possible to generate random numbers. You'll also see how to assign that generated number to a Captivate variable with the function setVariableValue from the API. That will allow to use the same slide for several sum questions. I will use the Multi-state object feature of Captivate 9 several times as well. In the next parts you'll also learn about retrieving a Captivate variable value with getVariableValue, how to format a number to specific number of decimals, how to avoid dividing by 0 (zero).

Scenario Summing slide

User will be allowed to choose for sums consisting of 2 up to 4 terms. The number of terms can be changed after completion of one exercise.

For a correct answer, the stick figure will change to another state, and a star will be added to the progress bar (also a multi-state object). For an incorrect answer the stick figure also changes to a state but no star will be ended to the progress bar.

After completion of 5 correct sums, the stick figure will change to a Next button. The user could still add more questions, but no more 'stars' will be added to the progress bar. 

In this screenshot, from HTML output, you'll see the situation after one successful answer, second sum has been created with 4 terms:

Used objects

Multi-state objects

Stick Character: see image Object States in Library below

OK/New shape button: see image Object States in Library below

Progress bar: see image Object States in Library below 

Special objects

Radio buttons - works perfectly for SWF output but formatting is not preserved for HTML output; labeled "Wd_TermNumber"

Scrolling Text interaction for SWF output, labeled "Wd_SumResult". It is possible to change the shown content in this interaction by changing the associated variable (v_result). However that functionality only works for SWF, not for HTML output. For that reason I needed an alternative which is a  

Text Entry Box, labeled "TEB_result" combined with the CpExtra widget and a specific command variable for HTML output. Since there is a bug in Captivate 9, which prevents using a TEB multiple times on a slide, I used a workaround. The default Submit button was deleted. It was replaced by a custom shape button (SB_CheckSum in the timeline) to trigger an advanced action. In this case an easy workaround, since I used that same shape button for the Scrolling Text Interaction for SWF output. The associated variable for the TEB is the same as for the Scrolling Text Interaction (v_result). Nothing had to be changed to the advanced action 'CheckSum' when replacing the Scrolling Text Interaction by a TEB.

Variables

v_one, v_two, v_three, v_four: will get the values for the (possible) 4 terms of the sum which are generated by the advanced action 'SumTerms'

v_result: will store the result value typed in by the user in the Scrolling Text interaction (SWF) or the TEB (HTML)

v_check: will be calculated and used to validate the result given by the learner in the advanced action 'CheckSum'

v_progress: is a counter for the correct answers, will be used to change the state of the progress bar

v_null: empty variable used to clear the content of the displayed result for a new sum (see Where is Null?)

xprefTEBUpdateFromVariable: only for HTML output, one of the CpExtra variables. When assigning the value 1 to this variable (with CpExtra widget loaded either in the file, or headless) it is possible to change the associated variable of a TEB by an action, and it will be reflected immediately in the TEB. I used this to clear the result when defining a new sum.

Advanced Actions

In this particular case it was not possible to use shared actions. Two advanced actions, both conditional, were needed:

SumTerms, triggered by the OK button (SB_Terms) after choosing the number of terms

CheckSum, triggered by the Check button (SB_CheckSum) to validate the answer

This conditional action has 7 decisions.

The first decision 'Always' will calculate the sum. It doesn't matter that it always sums four terms, since the lacking terms are empty.

The second decision 'Checker', will check the entered value (v_result) with the correct value (v_check). It is the only decision with a Then and Else part. For correct answer, the state of the sticky character is changed, the counter (v_progress) is incremented,  the state of the button SB_Terms is changed to another state and enabled again, while the button SB_CheckSum is disabled. For an incorrect answer, the counter is not incremented, and the sticky character is changed to another state.

The 5 other decisions 'ProgressXxxx' check the value of v_progress and show the appropriate state for the progress bar. The last decision 'ProgressFive' will also change the sticky Character to its state GoNext and enable the click box to proceed to the next slide (subject of the next blog post, with Subtract exercises).

JavaScript for random numbers

In the documentation provide by the Captivate team about using the common JS interface, you'll find a description of creating random numbers:

Common JS Interface

In this example I wanted to generate a random number between 10 included) and 100 (not included). The script window for the decision 'TwoTerms' of the action SumTerms (see above) had to generate two random numbers, to be stored in v_one and v_two; for the decision 'FourTerms' 4 variables had to get a random number:

Short explanation of this code:

The JS method Math.random() generates a decimal number between 0 (included) and 1 (not included).

The multiplication Math.random()*(100-10) will result in a random (decimal) number between 0 (included) and 90 (not included).

The sum Math.random()*(100-10) + 10 will result in a random (decimal) number between 10 (included) and 100 (not included).

The JS method Math.floor(e) will cut off the decimals of the argument e, round iit down to the nearest integer. As a result the full expression used in the JS window  Math.floor(Math.random()*(100-10) + 10) will result in an integer between 10 (included) and 99 (included). 

The method from the common API setVariableValue(x,y) allows to assign the value from the second argument to the variable indicated in the first argument. Beware: the variable name has to be identified as a string (text) by putting it between single or double quotes. For the value, which is a number, you can use the expression explained above. It is a method of the cpAPIInterface which is in the window object. That explains the total line of code, which in JS always ends with a semicolon:
window.cpAPIInterface.setVariableValue("v_one", Math.floor(Math.random()*(100-10) + 10));

Conclusion