Not able to create dynamic instance of flash object - actionscript-3

Ok so i'm trying to display multiple instance of an object square(movie clip) on different location on screen.
var k1=0,k=0,p=0;
for (k1=0;k1<5;k1++)
{
drawrect(k,p);
k=k+101;
}
This above code is for number of times i want to display the object om screen horizontally in line.
import flash.display.MovieClip;
function drawrect(x1:Number,y1:Number){
// statements here
trace("Hello world!");
var MC_squre:MovieClip= new MovieClip();
MC_squre.x=x1;
MC_squre.y=y1;
addChild(MC_squre);
};
this Function is trying to declare instance of movieclip SQUARE and place it at given parameter in function.i might want to make it and array of the instance later too.i tried this code with just
var square:Sprite = new Sprite();
addChild(square);
square.graphics.lineStyle(3,0x000000);
square.graphics.beginFill(0x0000FF);
square.graphics.drawRect(0,0,100,100);
square.graphics.endFill();
and it worked but i want to now use it by library object not just on drawn shapes.

What you have to do is to make your object in the library accessible by actionscript.
To do that, go into the properties of that Clip, click on "Advanced", and check the box "Export for Actionscript".
When pressing "Ok", you will get a warning that such a class does not exist and it will be automatically generated. That is ok.
Whatever you put as a classname in the Properties, you then have to use to instanciate your objects. If it is for example MySquare, use that.
So your above code would look like this:
function drawrect(x1:Number,y1:Number){
// statements here
trace("Hello world!");
var MC_squre:MovieClip= new MySquare();
MC_squre.x=x1;
MC_squre.y=y1;
addChild(MC_squre);
};

Related

How to load a swf and interact with it?

I have tried SWFLoader, but the problem is the loaded content is MovieClip and I don't know how to interact with it, and the MovieClip#numChildren is zero.
And by the way, I can't pass the flashvars to the swf.
Firstly, you should know that there is no exact answer to your question as it depends on your loaded SWF (you know it or not, its display list, ...) but I'll put a simple example to explain things and you have to adapt it to your case.
For this example, let's say that we have a very simple SWF (the loaded SWF) which contain a TextField (called txt_url) and a button (a MovieClip, called btn_go).
The btn_go button will open the URL entered in the txt_url TextField.
For our second SWF (the loader), we will use a Loader object to load our first one (which is in this case will be the Loader.content) and then we will set the URL (the txt_url text) and trigger the click event on the btn_go button.
So here is an example of the code of our loader.swf :
var loader:Loader = new Loader();
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, on_SWFLoad);
loader.load(new URLRequest('loaded.swf'));
addChild(loader);
function on_SWFLoad(e:Event): void
{
// get our loaded SWF
var loaded_swf:DisplayObjectContainer = DisplayObjectContainer(loader.content);
// because we know our target objects, we can use "getChildByName()"
// set the URL
TextField(loaded_swf.getChildByName('txt_url')).text = 'http://www.example.com';
// open the URL in the browser by triggering the click event on the "btn_go" button
MovieClip(loaded_swf.getChildByName('btn_go')).dispatchEvent(new MouseEvent(MouseEvent.CLICK));
}
This example will directly set and open the URL in the browser after loading the SWF, of course we can execute that action after clicking a button or something else but it's just a simple example to show you how you can do ...
Now, the problem is when we don't know anything about the loaded SWF and its children (names, depths, ...), in this case we should do more effort to do what we want : we should traverse the entire display list of the loaded SWF to identify the target objects.
Returning to our example and let's say that we only know that there are a TextField and a button in the stage, so our code can be like this for example :
function on_SWFLoad(e:Event): void
{
var loaded_swf:DisplayObjectContainer = DisplayObjectContainer(loader.content);
var num_children:int = loaded_swf.numChildren;
for(var i:int = 0; i < num_children; i++)
{
var child:DisplayObject = loaded_swf.getChildAt(i);
if(child is TextField)
{
trace(child.name); // gives : txt_url
TextField(child).text = 'http://www.example.com';
}
else
{
if(child.hasEventListener(MouseEvent.CLICK))
{
trace(child.name); // gives : btn_go
child.dispatchEvent(new MouseEvent(MouseEvent.CLICK));
}
}
}
}
Again, it's a very simple example just to show how we can proceed ...
...
Then about passing values (params) between SWFs, take a look on my answer of this question where you have a little example for that.
For more about Display programming (display list, display object, display object container, ...) take a look here.
Hope that can help.

How to make an instance move

I got the following code and the flash events are all loaded properly. ball is a movie clip and is assigned a class.
var speedx: Number=5;
var speedy: Number=3;
var myball = new ball();
addChild(myball);
addEventListener(Event:ENTER_FRAME,ballmove);
function ballmove(e:Event):void{
myball.x+=speedx;
myball.y+=speedy;
}
But now the instance myball won't move, it is just stuck at position 0,0. Kindly help me and advice how to get this myball to move along a staright line..
If I had dragged and dropped the instance from the library, then
myball.x+=speedx;
myball.y+=speedy;
worked perfectly, but doesn't work after addChild is given.
In your code you incorrectly used Event:ENTER_FRAME when it should be : Event.ENTER_FRAME. I wonder if there is a "silent" error? When testing movies, use Ctrl+Shift+Enter to run the debugger (gives better feedback on issues/errors).
var myball = new ball(); does not mean anything. You declare instance by using this logic : var Name : Type of Data = Value, In your code here you've said only that var Name = Value. Surprisingly it works but I wonder if getting comfortable with that could lead to issues on bigger future projects?
Instance name only affects objects already on Stage. If you're adding by code (from Library) make sure you create a new instance of object by using its Linkage name.
Solution :
In the library, right-click the "ball" object and choose "properties", in there make sure "name" is ball and tick "Export for ActionScript" (you should see "Class" becomeClass: ball). OK that.
Now in your code, you can create new instance by : var myball: ball = new ball();...
Your code should look like
var speedx: Number=5;
var speedy: Number=3;
var myball: ball = new ball();
addChild(myball);
addEventListener(Event.ENTER_FRAME, ballmove);
function ballmove(e:Event):void
{
myball.x += speedx;
myball.y += speedy;
}

Making a simple tamagoci game getting no compiler errors but receiving no output

Kind of new Actionscript and I'm just trying to make a simple tamagoci game. I've wrote all the code out but and receiving no compiler errors but for some reason I'm also not receiving any output messages for my mouse event listeners. Here is all my code, I really can't find the problem and any help would be greatly appreciated. Thanks.
package{
import flash.display.MovieClip;
import flash.events.MouseEvent;
public class Main extends MovieClip{
public var feedButton:MovieClip;
public var tamagoci:MovieClip;
public var disButton:MovieClip;
public var dietButton:MovieClip;
public function Main() {
this.init();
}
private function init():void {
this.feedButton.addEventListener(MouseEvent.MOUSE_DOWN, onfeedMouseDownHandler);
this.disButton.addEventListener(MouseEvent.MOUSE_DOWN, ondisMouseDownHandler);
this.dietButton.addEventListener(MouseEvent.MOUSE_DOWN, ondietMouseDownHandler);
}
private function onfeedMouseDownHandler(event:MouseEvent)void{
this.tamagoci.scaleX += 0.1;
this.tamagoci.scaleY += 0.1;
}
private function ondisMouseDownHandler(event:MouseEvent)void{
this.tamagoci.gotoAndPlay(5);
}
private function ondietMouseDownHandler(event:MouseEvent)void{
this.tamagoci.scaleX -= 0.1;
this.tamagoci.scaleY -= 0.1;
}
Are you using Flash Professional?
You're declaring your variable types in your class here;
public var feedButton:MovieClip;
public var tamagoci:MovieClip;
public var disButton:MovieClip;
public var dietButton:MovieClip;
But then in your constructor, all you are doing is running init();
public function Main() {
this.init();
}
So, this could one of a few things. The most likely is that you have declared your variables, but you haven't initialised them. You've created the variables to hold your objects, but according to your code, they're empty. More specifically, a variable or class property that doesn't assign an object to a variable of an object type will contain a default value of null.
You could prove this in your code by simply putting a condition inside your init(); method;
if(tamagoci == null){
trace("I haven't been assigned an object of type class yet!")
}
So it could be 1 of these 3 things:
1: If you have written your own classes for these class properties/variables, then you need to instantiate them with the new keyword. The general syntax is;
variable_name = new ClassName(parameter_1, parameter_2);
If you are using classes you have written yourself, you have to create an instance of the object, assign it to a variable, and then add it to the stage using addChild();. For example, lets say you've written your own Tamagoci class;
tamagoci = new Tamagoci();
tamagoci.x = 100; // set the x location
tamagoci.y = 200; // set the y location
addChild(tamagoci);
Notice the use of Tamagoci. This is just an example, but this is the class name, which shouldn't be confused with variable/property name. It could just have easily been;
tamagoci = new MovieClip();
But then, this is just an empty MovieClip. It needs a property to display on the screen. A Shape, A Bitmap, or another container class object like MovieClip or Sprite (container classes allow you to nest display objects inside them). But on a basic level, it must contain a visual component to appear on the stage.
2:
Have you made Main your document class? This is the class which will get automatically called when your Flash movie plays. To set this, click on your stage, and in the properties dialogue box on the right, under PUBLISH, type in the name of your class, which is "Main".
3:
If you have created MovieClips in your library in Flash Professional, then you need to go to your library, right click the MovieClips, and select properties. From there, you need to make sure Export for Actionscript is ticked.
Now, if you click on your MovieClips on the stage, then open the Properties tab in the top right of Flash Professional's default layout, then right at the top should be a text field, and if you hover over it, Instance name will pop up as a tool tip. This is where you name your stage objects. Once that is done, you have access to them in your timeline.
If this is how you've done this, then you don't need to declare the variables in your main class, as they are already declared on your stage by Flash Professional and instantiated automatically.

How can I give flash stage instances unique properties in Flash Professional to pass to AS3 script?

I've started building a rough game engine framework in Flash Professional and I'm curious how I can create objects in the Flash library that I'm able to drag onto the stage and assign properties that are accessible from AS3.
Example:
I want to create a switch object (e.g. a light switch), so that when the player interactes with it, it triggers something specific in code such as a light in the room turns on.
I understand that Flash has built in UI components that you can define properties within the Flash Professional environment (see image below), and I'm wondering if there's a way to create my own custom style components so that I can essentially have my level file open in flash (.fla) and then drag a switch component from my library, and type in some information such as what light it is controlling, and any other information I want.
(above is an example of the type of parameter control I'm looking for)
I've read a bit about extending the flash UIComponent class but I feel that that's not the right approach because it's overkill for what I want. All I want is to pass some basic parameters from a library stage instance into AS3. I do not want to pass data via the instance name because this seems very messy if I want to have more complex interaction.
Thanks!
I would create a "switch" movie clip and export it to actionscrip, same with a "light" movie clip. The in the main class .as file I would inset them into the stage, using addChild (clips) and then add a click listener to the "switch" movie clip to control the "light".
This can be easily done.
Component(s) are wrong approach in my opinion.
Firstly you would want to setup Actionscript linkage / label your Library item.
In Library Panel.
- Right Click on "yourMC" >> click "Properties".
- In Properties dialog Tick "Export for Action Script"
- Then Name your Class eg "yourMC_Class"
now MC is ready to be referenced in your code.
next you would want to Dynamically add your "yourMC" from library to stage.
which can be done like such.
// first reference library item
var yourMC_ref:yourMC_Class = new yourMC_Class();
// Then load dynamic mc item into var
var your_MC_OBJ = yourMC_ref;
// then add your MC to stage.
this.addChild(your_MC_OBJ);
your_MC_OBJ.x = 200;
your_MC_OBJ.y = 100;
in a nutshell that's how I add library items to stage.
Obviously thats the basic function / code.
In a project I would have all code in an external class, in which case you would just set vars as public vars
public var yourMC_ref:yourMC_Class = new yourMC_Class();
public var your_MC_OBJ = yourMC_ref;
and the last 3 lines of code into a public function
public function ADD_First_MC()
{
this.addChild(your_MC_OBJ);
your_MC_OBJ.x = 200;
your_MC_OBJ.y = 100;
}
Now 'your_MC_OBJ' can be used in more complex ways.
eg. to create a light switch there are many options depending on how you need to approch functionality.
eg. Apply a different MC library item to "your_MC_OBJ"
play specific frame within MCs.
However If it was me I would just use mouse function to switch light on or off using addChild removeChild.
eg.
public var LightON = 0;
public var yourMC_ref:yourMC_Class = new yourMC_Class();
public var your_MC_OBJ = yourMC_ref;
then create a public function that handles on / off events
public function LightON_OFF()
{
if(LightON == 1)
{
this.addChild(your_MC_OBJ);
your_MC_OBJ.x = 200;
your_MC_OBJ.y = 100;
}
if(LightON == 0)
{
this.removeChild(your_MC_OBJ);
}
}
Hope this helps.
So, for what you want, while it may not be the best way to do what you want, I understand it's your experience you are constructing.
Use components, yes...in the following way (the most simple one):
Create a Movie Clip
Right-click it in library
Click on "Component Definitions"
Add a property, set a name, a variable name (var test, for this matter) and a default value
Click OK
Open your movie clip
Open code for the first frame and declare the variable without an initial value (var test:String;)
Trace it's value ( trace( test ); )
Go back to the stage root
Drag and drop the item from library to stage
Test it (Cmd/Ctrl + Enter) (maybe it will print null, dunno why, it ignores the default value sometimes)
Select your component on stage
Open the properties panel (Windows > Properties)
Go to Component Parameters on this panel and change the property value
You should see the value traced on console
And, I think, like this you can use properties from components for what you want, like using a String and getting the controlled mc by its name.
Good luck
I think what people are trying to say is that you can have the whole thing is data driven, and so you can combine the IDE with the data to come up with your final game.
But consider this ... it might be what you want.
If you have, for instance, a BaseSwitch Class:
public Class BaseSwitch extends MovieClip {
private var _lightName:String;
private var _light:Light;
public function get lightName():String {
return lightName;
}
public function set lightName(value:String):void {
if (value != _lightName) {
_lightnName = value;
//Note I don't advocate having children reach into their parents like this,
//but you sound like you don't want the parent involved in the process, so
//this is one way you could do it.
if (parent.hasOwnProperty(lightName) && parent[lightName] is Light) {
_light = parent[lightName];
} else {
trace('Could not find light', _lightName);
}
}
}
//other code to listen for gestures and operate the light
}
Now, when you want a switch to operate a specific light name, create a library instance and set its base class to BaseSwitch. When you close the dialog where you set the base Class, you'll notice that it gives you a dialogue that it couldn't find the Class in the Class path and one will be generated. You're going to replace it with a Class that sets the lightName. Create a new AS3 Class in the root directory with the same name as your library instance. It should look something like this:
public class SpecificSwitch {
public function SpecificSwitch() {
super();
lightName = 'theSwitch';
}
}
Other possible choices involve having the parent Class match up instances of switch with instances of light based on name, so if it finds a light1 and a light1Switch, it either gives a reference to the light to the switch or it simply sets up a mapping in its own event listening system.

Stage and classes

I am new to AS3 and am trying to lean its OOP ways. What I am having problems with is understanding how to access the stage with separate classes.
Here is an example of what I am trying to do:
package game{
import flash.display.*;
public class Main extends MovieClip{
function Main(){
var player = new Player();
var playerBullets = new playerBullet();
addChild(player.players);
}
}
package game{
import flash.display.*;
public class Bullet extends Main // also tried with MovieClip and Sprite{
function Bullet(){
// empty
}
function blah(){
var someSprite = new someSprite();
Main.addChild(someSprite);
stage.addChild(someSprite);
root.addChild(someSprite);
}
}
}
I have Omitted another class which calls the blah method as I feel it is not relevant.
Basically what I want to know is how to add things to the stage in classes as it lookes like I am missing something crucial.
*EDIT TO INCLUDE ERROR*
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at game::Bullet/blah()
at game::Player/fire()
You shouldn't necessarily be extending main to create something like a bullet class, this can be it's own class that extends Sprite or MovieClip. The stage object is considered a global object, as it is a singleton (except in the case of Adobe AIR where you can have one stage per NativeWindow that you spawn). So any object that extends DisplayObject or has DisplayObject in it's inheritance chain will by default have a reference to the stage via a getter, which is populated automatically when a displayObject is added to the display list. This can happen by either adding a clip directly to the root stage object or by adding a clip as a child of another clip, that eventually connects to the stage. For example:
var clip1:MovieClip = new MovieClip();
stage.addChild(clip1); //Clip 1 can now access the stage reference internally.
ver clip2:MovieClip = new MovieClip(); //Right now, clip2 cannot access the stage reference interally.
clip1.addChild(clip2); //Now clip2 can access the internal stage reference because it has been connected to the display list through clip1.
The other mistake people make is accessing stage within a DisplayObject typed class (such as your Main class) without first ensuring that the object itself has been added to the stage. You do this by listening for the Event.ADDED_TO_STAGE event within the constructor of the class, like so:
public class Main extends MovieClip{
function Main(){
if(stage){
//The stage reference is present, so we're already added to the stage
init();
}else{
addEventListener(Event.ADDED_TO_STAGE, init);
}
var player = new Player();
var playerBullets = new playerBullet();
addChild(player.players);
}
private function init(e:Event = null)
{
trace("Added to stage, the stage reference is now populated and stage can be accessed");
}
}
This could be the problem you're having, but it's hard to say since you have not specified any errors. However, this is likely an issue or will be for you, since it's quite common. Inside the init() method you can then set a flag so that when external classes call your Main.blah() method, you can ensure that the stage reference exists before attempting to add something to the stage. Take note however that within your Main class when you simply say:
addChild(someChild);
or
this.addChild(someChild);
you're not adding that child to the stage, but rather to the Main object, which is a MovieClip or Sprite based object that is itself attached to the stage automatically when you set it as the Document class. Hope this info helps.
Update
To explain the display list a little more:
Think of all your movieclips as dishes, and the stage as the table. You can only access the table from the dish, if the dish is placed directly on the table, or if a dish is stacked on top of another dish that touches the table. If you have 10 plates stacked on top of each other, they all touch the table eventually, via their connection to each other. This is essentially a visualization of the flash display list. The way you put dishes on the table is by using addChild(dish). If you have not placed an object somewhere on the table, and try to access the table from that object, you're going to fail. You're getting the "access to undefined" error because you're calling the "blah()" method, which accesses the stage (table) before the bullet (dish) has been added to the stage (table). So you must first either directly add the bullet to the stage, or add it to another object that has already been added to the stage. Change your code like so:
var myBullet:Bullet = new Bullet();
stage.addChild(myBullet);
//Or, if this class, assuming it's the player class, has already been added to the stage, just do this:
this.addChild(myBullet);
myBullet.blah();
Even so, you should still have some error checking within your "blah" method to ensure that the stage is available:
function blah(){
var someSprite = new someSprite();
if(stage){
Main.addChild(someSprite);
stage.addChild(someSprite);
root.addChild(someSprite);
}else{
trace("error, stage not present");
}
}
However you should also note that by adding this child to Main, then stage, then root all in sequence, this does not duplicate the someSprite object. When you add a display object to a new parent object, the object is automatically pulled from it's current parent and moved to the new one. So all this code will do is eventually add someSprite to root, which I believe will fail because root is not a display object, but rather a global reference mainly used to access global objects such as the stage and the Loader object used to load the SWF.
You shouldn't ever be calling stage.addChild. There should be only one child of the Stage, and that's the document class.
You make a MovieClip display on the screen by adding it to the stage's display list.
Stage
+ Main Timeline
+Anything
+Else
+You
+Want
So assuming that Main is your document class for the main timeline...
// inside of Main's constructor...
public function Main(){
var anything:MovieClip = new MovieClip();
var Else:TextField = new TextField();
var you:SimpleButton = new SimpleButton();
var want:Sprite = new Sprite();
this.addChild(anything);
this.addChild(Else);
this.addChild(you);
this.addChild(want);
}
Then in order to add children even lower, for example if you want something to be a child of "Anything" such that you have....
Stage
+ Main Timeline
+Anything
+And
+Everything
+Else
+You
+Want
public function Main(){
var anything:MovieClip = new MovieClip();
var Else:TextField = new TextField();
var you:SimpleButton = new SimpleButton();
var want:Sprite = new Sprite();
this.addChild(anything);
this.addChild(Else);
this.addChild(you);
this.addChild(want);
var And:Sprite = new Sprite();
var everything:Sprite = new Sprite();
anything.addChild(And);
anything.addChild(everything);
}
EDIT: Ascension Systems asks why you should never add any display object directly as a child of the stage. The simplest answer is that you can't ever guarantee that what you believe you're creating as a document class, or as a main timeline in fact actually is going to be used as such. Your use of the stage may later preclude your swf from being loaded as a child of a larger application depending on what it is you've done, exactly. Relying directly on the stage can mean that you're making some assumptions about the nature of the display list that may not hold in the future. That's the way in which it breaks modularity (which is not the same as breaking oop).
Why add to the stage when you could just create your entire application as a MovieClip that is completely self-contained with no reliance on the concept of a "stage" beyond that which is required for learning world coordinates? That way you can be much more modular in your design and you sacrifice nothing.
In some people's work this may be considered an edge case. In my work this has happened both to me when I've created applications that I thought at the time were purely stand-alone that ended up being repurposed later to be a module, and also to swfs that other people created that were intended to be strictly stand-alone, but that I was then to integrate as a module into a larger application. In all cases there were some nasty side effects to contend with. That's where I learned not to rely too closely on the stage for much beyond world coordinates.
Every display object has a property called stage, which is null until that object is added to the display tree.
When you are unsure if an object has been added to the stage, there is a listener you can employ for that purpose:
public class Main extends MovieClip
{
import flash.events.Event;
public function Main():void
{
if(stage) {
init();
} else {
this.addEventListener(Event.ADDED_TO_STAGE,init);
}
}
private function init(evt:Event = null):void
{
this.removeEventListener(Event.ADDED_TO_STAGE,init);
//object is now definitely on the display tree
}
}
I'm gonna take a wild stab in the dark here.
stage is a property implemented something like so:
public function get stage():Stage {
var s:DisplayObject = this;
while(s.parent) s = s.parent;
return s as Stage;
}
root is very similar but stops a level below stage (root is a child of stage).
These properties only work when the object you're calling them on is on the stage somewhere. Doesn't matter where, because the while loop will walk up the hierarchy to get to the stage node at the top. But if it's not on the stage, then parent will be null.
So if your movieclip is not on the stage, then its reference to stage will be null. Same goes for root.
I'm guessing that you're calling blah before the bullets are added to the stage? In which case your call stage.addChild(someSprite) will be a Null Reference error (stage is null).
So you either need to add the bullets to stage first, or you need to pass stage in as a parameter:
function blah(s:Stage){
var someSprite = new someSprite();
s.addChild(someSprite);
}