Author: Nick Kuh | Website: http://www.editioninteractive.co.uk

You can create your own class containing initialised properties and then apply it to new objects which will inherit these from the class. Here is a simple example:

//first create the class:

function Human (name,sex) {
	//properties of the Human object
	this.sex = sex;
	this.name = name;
	//objects contained within the Human which will hold their own properties 
	this.head = {};
	this.body = {};
	this.arms = {}
	this.legs = {};
}

Nick = new Human("Nick","male");
Nicole = new Human("Nicole","female");
trace("Nick is a "+Nick.sex+". Nicole is a "+Nicole.sex+".");

A class is defined in ActionScript using the function method. It is good practice to capitalise classes to distinguish them from regular functions. In the example, we have made efficient use of ActionScript by defining the class just once and from then on new Human objects can be created by using one line of ActionScript. When an object is defined you can use either of the following methods to add properties to it:

this.head = {};
this.head.hairColour = 0x663399;
this.bigNose = true;

//or

this.head = {hairColour : 0x663399, bigNose : true};

I prefer to use the second method. Add this to the Human class:

function Human (name,sex) {
	this.name = name;
	this.sex = sex;
	this.fReferers();
	this.head = {hairColour : 0x663399, bigNose : true};
	this.body = {};
	//introducing class methods
	this.fCreateArms(false,true);
	this.fCreateLegs(true,true);
}

You'll notice that I've changed arms and legs in the Human class and added a new method call 'fReferers'. Here I'm calling methods of the Human class which will generate the arms and legs and a method which will create string references which I can use when dynamically creating sentences about my new male Human. Now to create the Human methods:

Human.prototype.fCreateArms = function (leftArmWaving,rightArmWaving) {
	this.arms = {};
	//short cut
	var sc = this.arms;
	sc.armLeft = { bWaving:leftArmWaving }
	sc.armRight = { bWaving:rightArmWaving }
}

Human.prototype.fReferers = function () {
	if(this.sex == "male") {
		this.referers = {n1 : "He", n2 : "His"};
	}
	else{
		this.referers = {n1 : "She", n2 : "Her"};
	}
}

You must use the prototype when creating class methods as it enables these methods to be called by any new object instance of the Human class.

» Level Intermediate

Added: 2003-01-01 Rating: 7 Votes: 27

» Author

I am a Flash Developer with 3 years commercial experience programming database-driven games and applications. I am currently working on a contract job developing e-learning software for UK schools.

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