ActionScript for Flash MX: The Definitive Guide, Second Edition

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Chapter 9: Functions

Voilà! With both answer( ) and gradeUser( ) created and our quiz variables initial-

ized, the logic of our quiz system is complete. Notice how much easier it is to follow

the quiz’s operation when most of the code is contained in a single frame. All that’s

left is to call the answer( ) function from the appropriate buttons in the quiz.

Calling the answer( ) function

We’ll call the answer( ) function from the buttons that the user clicks to indicate

answers. Here’s the code for the “Answer 1” button:

choice1_btn.onRelease = function ( ) {

this._parent.answer(1);

};

This code assigns a function literal to the choice1_btn’s onRelease( ) handler, which is

invoked automatically when the button is pressed. The function literal contains a

single statement that says, “On the movie clip timeline that contains this button,

this._parent, invoke answer( ), passing the user’s choice for this question (1) as an

argument:

this._parent.answer(1);”

Notice that the

choice1_btn handler applies to any question, so we don’t have to

assign new button handlers for each question (as we did in the first quiz). The but-

ton’s job is simply to tell the answer( ) function which choice the user made. The

answer( ) function keeps track of which question the user is answering, so it records