The Variable Changed trigger allows you to trigger an action when the contents of the variable you specify changes value. This trigger is used in a variety of publications, for example:
(i) in quiz publications scores can be saved in a variable, when the student reaches a particular score, the variable triggers a list of actions to: display the results on-screen to the student; store the results in a text file; and email them to the tutor.
(ii) in database publications when a new record is displayed on-screen, the Get Current Record Number action can be triggered because the variable attached to this action will have changed when the new record is displayed.
(iii) in game publications when a score variable reaches a particular score, a bonus player may be given to the user.
These are just some examples of why you would want to use this trigger.
Note:
This trigger does not check the actual content of the variable it only triggers the list of actions when the content of the variable changes value. If you want to check the contents of the variable (e.g. is the variable equal to or above 50? Or does the variable contain the word yes or no?) you must use the If action in the Programming menu of the Programming tab of the Actions dialog.
The If action is often used with the Variable Changed trigger because you may not want to start a list of actions unless the variable contains a specific value. Equally, you may want to start different lists of actions depending on the contents of the variable.
Setting up the Variable Changed trigger:
1. Add the Variable Changed trigger to your Actions Organiser, as described in Creating and Editing Actions. The Variable Changed tab will automatically appear when you add the trigger.
2. Click on the down arrow to the right of the Variable option, to select the name of the variable you want to use as the trigger.
Note:
This trigger is activated the next time the contents of the variable you have selected changes.
3. Click on the Apply button to save your changes.
4. Click on the Actions tab in the Actions dialog to select an action or actions to add to the trigger.
5. Go to Choosing an Action to list all of the actions you can add to your trigger.