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DigHT 310
Efficient Design of User Interactions

In this lecture I will present four different ways of programming essentially the same interaction--a simple True/False exercise--as a means of demonstrating efficient ways of using the structure of LiveCode to create user interactions. At the end of this presentation you will have a chance to try some of these techniques for yourself.

These examples are illustrated in the stack http://dight210.byu.edu/resources/InClass_Work/QuizStacks/InteractionsProgrammingEx.rev.

Method 1 - The way a novice programmer might do it.

Already have a background group with all navigation controls on it.
Create a new group (named "questionControls") with question objects in it:


Question field
Feedback field

Create a third group with the answer buttons in it:


True button, false button (radio style)


This group will have to be duplicated on each new card.

Scripts:


True/False buttons: MouseUp handler which puts appropriate feedback into the feedback field, according to what right answer is.
Card script: openCard handler to empty out the feedback field and reset buttons

Advantages of this approach:

• fast and simple to set up.


Disadvantages of this approach:

• have to type each new question into the field each time add a new card.
• Have to change correct, incorrect answer feedback in buttons each time.

Method 2 - Getting smarter

Merge the true/false buttons into the questionControls group. Delete the extra true/false groups

Scripts:


Card Script: Add to openCard handler, set the custom property of the question group. Be sure to include pass openCard command to ensure the message gets passed to the bgControls group.
QuestionControls group: check the short name of the selected button, compare it to the correctAnswer property

Advantage:

• more generalized, response feedback not hard-coded in true/false buttons.


Disadvantages:

• Still have to modify card script on each new card to set correct answer property
• Still have to type in each new question.

Method 3 - More generalized, more efficient

Same groups

Use custom property of questionControls group to put all questions and correct answers in a list

Scripts:


Now we can move the openCard handler to questionControls group, because we don't have to hard code the answer on each openCard; check questionlist property on each new card and fill in question fld and correctAnswer property from script

Advantages:

• No more hard coding individual cards; questions all in one place for quick editing
• Can easily randomize order of questions


Disadvantages:

• Slightly more difficult scripting
• Still creating new card for each question (though this too can be scripted; would also require deleting all but first card when questions were through.

Method 4 - Single card approach

All groups same as above, but only one card is used. Simply replace data on the card for each new question.

Advantages:
• Very flexible, less cleanup
• Easy to change behavior because all scripting and question text is in a single place.


Disadvantages:

• More difficult scripting (though the payback is high once it's done.)