class code placement

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October 26th, 2003, 12:46 AM

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pogremar

Join Date: Jul 2003

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class code placement

I wrote c++ programs before so I'm familiar with classes. My question is about the placement of the source code in flash. Let me explain:
I want to make a class, say creature, that I can assign to movieclips on the stage and have them make use of the class.
for instance, say I have this code(which I don't know if it's correct).

PHP Code:


		
			
function CREATURE(obj) {

    this.obj = obj;

    this.speed = 5;

    this.move();

}

CREATURE.prototype.move = function() {

    if (key.isDown(key.LEFT)) {

        this.obj._x -= this.speed;

    }

    if (key.isDown(key.RIGHT)) {

        this.obj._x += this.speed;

    }

    if (key.isDown(key.UP)) {

        this.obj._y -= this.speed;

    }

    if (key.isDown(key.DOWN)) {

        this.obj._y += this.speed;

    }

};

Like I said, I want to have this code just once and then have the MCs make use of it. So, I figure I would do something like this.

onClipEvent (load) {
ball = new CREATURE(this);
}
onClipEvent (enterFrame) {
ball.move();
}

I figured I put the first code snnipet, the class definition, on the time line and then make a class intance on the particular object. This is not working though. What's the correct way to do this?

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October 26th, 2003, 06:31 AM

mushie

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depends on version really - 6 or 7??
version 6 (actionscript 1)

PHP Code:


		
			
//=================================

//     Create namespace in which to store classes

//=================================

if (_global.com == undefined) {

    _global.com = new Object();

}

if (_global.com.domain == undefined) {

    _global.com.domain = new Object();

}

//=================================

/*constructor */

namespace.ClassName = function() {

    // Create Instance properties.

    // no 'real' private and public in flash 6

    // Private

    this.privateProperty = value;

    // Public

    this.publicProperty = this.params.passedValue;

    // Initialise Instance.

    this.method(this.params.passedValue1, this.params.passedValue2);

    // Remove constructor params object from the Instance.

    delete this.params;

};

//

/* Set MovieClip as ClassName's superclass.*/

//

namespace.ClassName.prototype = new MovieClip();

//

/*Associate the Library's menu item symbol with ClassName class.*/

//

Object.registerClass("librarySymbolName", namespace.ClassName);

//

/* methods */

namespace.ClassName.prototype.method1= function(param) {

    this.property = param;

};

/*

.

.

.

*/

namespace.ClassName.prototype.methodN= function(param,obj,blah) {

    this.property = param;

    /*

    .

    */

};

//****************************************************//

// instantiate your object from your class

//

// create some parameters and store in an object

myObj = new Object();

myObj.param1=value1;

/*

.

.

*/

myObj.paramN=valueN;

//

// create obj to pass to constructor containing params

var initObj = new Object();

// add params object

initObj.params = myObj;

// create the instance - use of this depends on path, could be _root, _parent etc instead of 'this'

this.attachMovie("librarySymbolName", "instanceName", level, initObj);

// bingo, you're done :)

flash 2004 - same way of instantiating object, but you asign the class to the library item by right-click>>properties

like that.

hth

** admins, why are the lines double in the code????

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October 26th, 2003, 08:15 AM

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pogremar

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Thanks for the reply, but all the abstraction is confusing me. For instance:
namespace.ClassName
Which namespace do I use?
Also, where is all this code placed, in the timeline, instance or part in the timeline and part in the instance?

October 26th, 2003, 08:55 AM

mushie

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PHP Code:


		
			
//=================================

//     Create namespace in which to store classes

//=================================



if (_global.com == undefined) {

    _global.com = new Object();

}

if (_global.com.domain == undefined) {

    _global.com.domain = new Object();

}

//=================================

put that anywhere - you dont HAVE TO do this, it just makes things easier in the long run - its a workaround for namespaces in flash 6, dont need it in 7. essentially it creates an empty global object to store the classes in.
since the namespace object is global it allows easy access from anywhere as well.

so for com substitute your top level domain, and for domain your, um, domain name....

or call it oyster.orgy.from.hell if you must, it doesnt matter

everything up until

PHP Code:


		
			
// instantiate your object from your class

is the class definition
beneath that is the instantiation.

i put each of my class scripts in the first frame of the main timeline on a different layer, with another layer(s) for instantiating the classes - this is done with each as a function; i then have another function called main() that calls those functions.
finally i have a layer with a frame script of just

PHP Code:


		
			
 main();

to start everything.

everything willl ahve to be done in frame one of a movie unless you use
#initclip - look it up in the manual and on the web.

i though the abstraction was the way to go, rather than being asked where the 'varTracker' object was in the actionscript dictionary, and that i had commented quite clearly what each section did, sorry if that led to confusion.

clearer now? or still like mud?

Last edited by mushie : October 26th, 2003 at 08:58 AM.

October 26th, 2003, 09:31 AM

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pogremar

Join Date: Jul 2003

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still like mud. Thanks for the help, though. I guess I'm just not familiar enough, yet, with how flash handles objects. I will continue looking at some more examples.

October 26th, 2003, 11:38 AM

mushie

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Join Date: Sep 2003

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it is pretty ropey in flash; not helped by the fact that actionscript isnt exactly strict either.

heres a basic fla http://www.newmediascience.com/star.fla

very simple class declaration and instantiation, using an event listener to call the object method.

thats another problem, as movieclips dont have native event listeners - there is an undocumented (at least by macromedia) method for adding listeners to ANY objects called ASBroadcaster - have a look here, works great .
ASBroadcaster
ive just used an empty Object as a controller.

hth

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