AS3:public variable vs .this - actionscript-3

If there is a main class which uses class Chan, given two codes, for example
public class Chan extends Sprite
{
public function Chan():void
{
this.graphics.beginFill(0x123456);
this.graphics.drawRect(100,100,30,30);
}
}
And
public class Chan extends Sprite
{
public static var rect:Sprite=new Sprite();
public function Chan():void
{
rect.graphics.beginFill(0x123456);
rect.graphics.drawRect(100,100,30,30);
}
}
Why does one seems to work, and the other doesn't ?

scope. In the first example, you are drawing on the sprite instance itself that is already on the stage. rect in your second example is static and belongs to the class. So although you are drawing in it, it is not visible... it's only in memory. If you add one more line to the second example, it will also be visible.
public class Chan extends Sprite
{
public static var rect:Sprite=new Sprite();
public function Chan():void
{
rect.graphics.beginFill(0x123456);
rect.graphics.drawRect(100,100,30,30);
this.addChild(rect);
}
}
EDIT:
I wanted to elaborate on this a bit. The fact that rect was a static var wasn't the main problem. I mentioned it was static in my answer but didn't want that to confuse you. The reason it doesn't work is the scope where you were drawing wasn't in view... it was simply a variable. so even if it said:
public var rect:Sprite = new Sprite();
It would not be visible until you called addChild(rect) to actually add it into view.

Related

AS3 How to add a Class on the stage from a timer?

lots of help from you guys :). My next question is here :).
I have timer in class MyTimer.as and Thief1_mc.as movie clip.
How can I addChild(Thief1_mc) on the stage from MyTimer? Everything looks simple, the only problem is "stage" property. MyTimer class cannot send "stage" as an argument because is not on the stage itself. I tried adding MyTimer on the stage in Main class like addChild (MyTimer), the trace says MyTimer is on the stage but I still cannot pass the stage argument to the Thief1_mc. I need this argument to be sent because the class Thief1_mc has to add itself on the stage using the property "stage".
The code:
public class Thief1_mc extends MovieClip
{
//this variable type Stage will contain stage
private var stageHolder:Stage;
public function Thief1_mc()
{
//constructor
}
//function that creates this object with passed "stage" argument from the caller
public function createItself(st):void
{
//variable that contain the stage so I can use this argument anywhere in the class
stageHolder = st;
//i have to refer to the stage by passed "st" parameter to create this object
stageHolder.addChild(this);
//initial position
this.x = 380;
this.y = 230;
}
}
}
MyTimer class and "_thief1.createItself(stage)" caller with stage arument
public class MyTimer extends Sprite
{
private static var nCount:Number = 120;
private static var currentCount:Number;
private static var _timer:Timer = new Timer(1000,nCount);
private static var _timerDispather:Timer;
private static var _thief1:Thief1_mc = new Thief1_mc ;
public function MyTimer()
{
// constructor code
}
//another timer
private static function increaseInterval(interval:int):void
{
_timerDispather = new Timer(interval);
_timerDispather.addEventListener(TimerEvent.TIMER, onUpdateTimeAnotherTimer);
_timerDispather.start();
}
//another timer;
private static function onUpdateTimeAnotherTimer(e:Event):void
{
_thief1.createItself(stage);//the most important part
}
public static function activateTimer():void
{
currentCount = nCount;
_timer.addEventListener(TimerEvent.TIMER, onUpdateTime);
_timer.start();
}
public static function deactivateTimer():void
{
_timer.removeEventListener(TimerEvent.TIMER, onUpdateTime);
_timer.stop();
_timer.reset();
currentCount = nCount;
//another timer
_timerDispather.removeEventListener(TimerEvent.TIMER, onUpdateTimeAnotherTimer);
_timerDispather.stop();
_timerDispather.reset();
}
private static function onUpdateTime(e:Event):void
{
currentCount--;
if (currentCount == 0)
{
_timer.removeEventListener(TimerEvent.TIMER, onUpdateTime);
_timer.stop();
_timer.reset();
}
}
}
}
Your code is backwards in a few places. It does not flow very nicely, and the issues you having now are going to be tenfold at some stage in your project.
Firstly, your MyTimer class should not be extending Sprite. It does not get rendered and does not represent anything graphically.
Secondly, your timer class is taking on more than it should. I would revise it to manage your timers and timer events only. Create a list within your timer class that will contain some other elements which can have a method triggers to do other stuff, like creating and adding Thief1_mc.
A simplified version of this might look like:
public class Updater
{
private var _timer:Timer;
private var _toUpdate:Vector.<IUpdatable> = new Vector.<IUpdatable>();
public function Updater()
{
_timer = new Timer(60);
_timer.start();
_timer.addEventListener(TimerEvent.TIMER, _notifyUpdatables);
}
private function _notifyUpdatables(e:TimerEvent):void
{
for each(var i:IUpdatable in _toUpdate)
{
i.update(this);
}
}
public function addUpdatable(updatable:IUpdatable):void
{
_toUpdate.push(updatable);
}
public function removeUpdatable(updatable:IUpdatable):void
{
var index:int = _toUpdate.indexOf(updatable);
if(index >= 0) _toUpdate.splice(index, 1);
}
}
From here we need to create an interface which we will implement on classes that we want to be able to call update() on each time the Updater timer ticks:
public interface IUpdatable
{
function update(updater:Updater):void;
}
Now what I would do in your case is have a class that does extend Sprite and manages the graphics of the application / game. It will implement the IUpdatable interface like I have described and also could deal with adding your Thief1_mc:
public class View extends Sprite implements IUpdatable
{
public function update(updater:Updater):void
{
// Create a Thief.
var thief:Thief = new Thief();
updater.addUpdatable(thief);
addChild(thief);
}
}
Your Thief can take advantage of the IUpdatable interface we have and be added to the update queue when it is created, as I've done above. Just to have a complete example, here's the Thief class:
public class Thief extends Sprite implements IUpdatable
{
public function update(updater:Updater):void
{
// Make this Thief so some stuff.
//
}
}
And here's how you can tie it all together in your document class:
public class App extends Sprite
{
private var _updater:Updater;
private var _view:View;
public function App()
{
_updater = new Updater();
_view = new View();
_updater.addUpdatable(_view);
stage.addChild(_view);
}
}
This might be a bit overwhelming at first, and seem like a lot of work, but you now have a nice clean foundation to add more elements easily.
Rather than having your one class trying to manage timers and add Thieves like you had initially, we've separated the responsibilities and tightened up the flow a little. The Updater deals purely with storing IUpdatable instances and calling their update() method each time the Timer within it ticks. The View class manages the graphics and will also add a Thief each time it is updated via the Updater. The View was added to the stage initially, so all you need to do is add the thieves into itself to have them show up.
If you take this and restructure how the timers work within Updater, I think you'll be where you wanted but with a significantly better understanding and structure.

Animation in class files?

I've found myself needing to refer to certain animations in some unknown frame in my classes. What would be the best way to do this? Should I be creating a custum name and specify that all instances of the class should label a certain animation the same thing. For instance:
public class CanBeHurt{
public CanBeHurt() extends MovieClip{
// constructor code here
}
public function hurt():void{
gotoAndPlay("hurt");
}
}
Any instance of this class would then be forced to label the start of the hurt animation "hurt". Alternatively I could take in strings in the constructor that specify the frame, like so:
public class CanBeHurt{
private var hurtAnimationLabel: String;
public CanBeHurt(hurtAnimationLabel: String) extends MovieClip{
this.hurtAnimationLabel = hurtAnimationLabel;
}
public function hurt():void{
gotoAndPlay(hurtAnimationLabel);
}
}
But unfortunately with more complex objects, I already have a bunch of other input arguments for the constructor and with so many animations, I really don't want to add anymore to it. And lastly, the last option I came up with is:
public class CanBeHurt{
private var hurtAnimationLabel: String;
public CanBeHurt() extends MovieClip{
this.hurtAnimationLabel = this.currentLabels[0];
}
public function hurt():void{
gotoAndPlay(hurtAnimationLabel);
}
}
Unfortunately, with multiple animations, now I'm forced to have my animation labels in a certain order to be able to refer to them properly. Of the 3 methods, I've found the first one to be the most satisfying, but is there a better way?
You don't need to store label names, only if you want the efficient way.
Example:
public class CanBeHurt{
private var label: String;
public CanBeHurt() extends MovieClip{
label= "hurtLabel";
}
public function hurt():void{
currentFrameLabel != "hurtLabel" ? gotoAndPlay("hurtLabel") : null;
}
}
You should check the current frame's label and then play the animation to avoid frame stucking. (The animation is always at the first frame)
For games, most of the developers use a function to control the animations, it's the handleAnimation function.
Example:
public class Example{
private var label:String = "someLabel1";
public Example() extends MovieClip{
//constructor code here
}
private function handleAnimation(){
if(condition){
label = "someLabel1";
}
if(condition2){
label = "someLabel2";
}
gotoAndPlay(label);
}
}
I usually don't extend movieclip for my code. I create some kind of class that accepts a MovieClip in constructor and stores a reference to this and then acts upon it on function calls.
When it comes to label names I usually place them as a static variable in the appropriate class.
This has worked well for me throughout the years :)

ActionScript3: Inheriting constructor arguments from parents

I'm making a game in action script 3. In it, I have an actor class from which player and enemy classes will be derived. I'm doing this so that unless I need to provide specific AI or fancy behavior (such as for bosses), I can just make a new clip in the library for each enemy without making an actionscript file.
However, I've run into a problem.
Whenever I try to pass arguments to the construction of an enemy (make it spawn with more health), I get error 1136 (Incorrect number of arguments.)
This is because the constructor created automatically at runtime doesn't have the same arguments as it's parent class. Is there any way to get around this without making a class file where I copy and paste the parent constructor function for each of my hundreds of enemies?
Edit
actually rereading your question I think you may be looking for super();
Example
public class Actor{
private var myHelth:uint;
public function Actor(helth:uint = 100){
myHelth = helth; //this will be set to 100 if nothing it passed in or the value passed
}
}
Class that extends Actor:
public class Boss extends Actor{
public function Boss(){
super(200); //passes 200 to Actor;
}
}
If you're trying to pass data into a classes constructor you need to make sure it's accepting arguments.
public class Actor{
private var myHelth:uint;
public function Actor(helth:uint = 100){
myHelth = helth; //this will be set to 100 if nothing it passed in or the value passed
}
}
Then to use
var a:Actor = new Actor(200); //setting health to 200
var b:Actor = new Actor(); //using the default of 100
Make sure your symbols in Flash Pro have appropriate AS linkage, then use pass constructor arguments in super statements:
Actor - base class
package
{
public class Actor
{
public function Actor(name:String, role:String)
{
}
}
}
Player - inherits from Actor defining its own constructor parameters:
package
{
public final class Player extends Actor
{
public function Player(... params:Array)
{
// pass desired inherited constructor parameters
super("name", "role");
}
}
}
Enemy - inherits from Actor defining its own constructor parameters:
package
{
public final class Enemy extends Actor
{
public function Enemy(... params:Array)
{
// pass desired inherited constructor parameters
super("name", "role");
}
}
}

Controlling/initializing external Class [AS3]

Before firing away, I know there are many questions here on SO that are quite similar. Yet, none of the solutions given were of any help to me, probably because my case is a little different.
I have a main class which loads an external class (separate .as file). In this external class, there are several objects which have tweens and time events bound to them.
What I want to do, is starting the animations when a certain function is called in my Main class. However, I've tried numerous things to stop and/or reset the animations in the external class, so it will start from the beginning if the required function in Main is called.
Main.as:
package {
//required imports
public class Main extends MovieClip {
var myClass:MyClass = new MyClass; //this is the external class
var button:Button = new Button; //movieclip in the library
public function Main() {
addChild(myClass); //I want to do this here so the objects show from the start
//try 1: myClass.gotoAndStop(1);
//try 2: myClass.stop();
button.addEventListener(MouseEvent.MOUSE_CLICK, playAnimation);
}
function playAnimation (e:MouseEvent) {
//try 1: myClass.gotoAndPlay(1);
//try 2: myClass.start();
//try 3: controlling the startTweening() function in MyClass, I tried different ways
}
}
}
The problem starts in the Main class above. I don't want to animate yet!
MyClass.as:
package {
//required imports
public class MyClass extends MovieClip {
//vars
public function MyClass() {
startTweening();
}
function startTweening() {
//tween event
//calling next function (with use of a TimerEvent) after tween is done. This is repeated several times.
}
}
}
Everything in this class works fine, so that's not the problem.
If this makes any difference, I used TweenMax in MyClass for tweening. I didn't use the timeline in the .fla.
Any help would greatly appreciated!
If you don't want to animate at creation of MyClass remove startTweening(); call from the constructor of MyClass.
Make startTweening(); a public function and call it whenever your need with myClass.startTweening().
Here the MyClass
public class MyClass extends MovieClip {
//vars
public function MyClass() {
}
public function startTweening() {
//tween event
//calling next function (with use of a TimerEvent) after tween is done. This is repeated several times.
}
}
and here the Main class
public class Main extends MovieClip {
var myClass:MyClass;
var button:Button = new Button; //movieclip in the library
public function Main() {
myClass = addChild(new MyClass()) as MyClass;
button.addEventListener(MouseEvent.MOUSE_CLICK, playAnimation);
}
function playAnimation (e:MouseEvent) {
myClass.startTweening();
}
}

Controlling objects of another class that are already on the stage

I'm quite ashemed to ask this question here because I'm sure that I'm missing something very basic. I'm not even sure what should be the correct title for this question.
Let's say that I've a button object (instance of Flip) and a coin object (instance of Coin) on the stage. The coin object has two frames: one showing Heads and one for Tails.
MyCoin class is as following:
package
{
import flash.display.MovieClip;
public class Coin extends MovieClip
{
protected var _coinFace:uint;
public function Coin()
{
stop();
}
public function get coinFace():uint {
return _coinFace;
}
public function set coinFace(value:uint):void {
_coinFace = value;
}
public function show():void {
gotoAndStop(_coinFace);
}
}
}
Objective: When user clicks the button, the coin should flip and show a random coinFace. I've added an eventListener to the Flip class as follows:
public function Flip()
{
this.addEventListener(MouseEvent.CLICK, onMouseClick);
}
Problem: How do I reach the coin object on the screen via onMouseClick function? Let's say that the object on the stage has instance name of myCoin. I suppose that had I not done this with an external class and simply used actions from the frame I could just use the instance name as a variable. I couldn't figure to do the same it in an external class. Do I first create the object which is already on the stage?
Where you create the instance of each, the flip object needs to be passed an instance of the coin object.
var myCoin:Coin = new Coin();
var myFlip:Flip = new Flip(myCoin);
Then inside the Flip class:
private var _coin:Coin;
public function Flip(coin:Coin) {
_coin = coin;
this.addEventListener(MouseEvent.CLICK, onMouseClick);
}
private function onMouseClick(e:MouseEvent):void {
_coin.gotoAndStop(2); // Or what ever needs to be done to the coin on click
}
Alternatively, depending on the complexity of the overall structure, you can a build a control class that acts as a link between the two.