In AS3 - I use a generic button handler to deal with on-click events on a movie clip object. For the last 4 hours I’ve been trying to add an image to this movie clip (see * * *) object.
The code (I cut and pasted a bit but this all compiles without any errors)
btPlay = new mcButtonPlay(this,"ClickMe",GameImage); // GameImage is an BitmapData object
public class mcButtonPlay extends navigationButtonHandler {
public function mcButtonPlay(Parent:MovieClip,Text:String,GameImage:BitmapData) {
super(Text);
if (GameImage != null) {
var ImageBitMap:Bitmap = new Bitmap(GameImage);
this.addChild(ImageBitMap); // * * * This doesn’t show
Parent.addChild(ImageBitMap); // Works just to test the image
}
}
}
public class navigationButtonHandler extends MovieClip {
public function navigationButtonHandler(Text:String) {
ChangeButtonTargetText(Text);
Parent.addChild(this);
}
}
public class navigationButtonHandler extends MovieClip {
public function navigationButtonHandler(Text:String) {
ChangeButtonTargetText(Text);
Parent.addChild(this); //<--------????
}
}
where does Parent come from in the above piece of code copied from the question? It would seem the navigationButtonHandler class never gets added to the stage because it doesn't get a Parent? So the extended class also is never added to the stage which would be why your image is never shown if you addChild it to your mcButtonPlay class.
Your extended constructor DOES pass a Parent parameter but the base class doesn't. That seems weird to me and should not compile. Or are you doing some static things behind the scenes?
And get to work on your capitalization style as mentioned in the comments. It's really a lot easier to read and find errors if you follow common conventions!
this.addChild(ImageBitMap); // * * * This doesn’t show
Parent.addChild(ImageBitMap); // Works just to test the image
With this code, ImageBitMap is being removed from 'this' and placed in 'Parent', so you will never see it in 'this'.
Remove that second line and tell me if it's still working.
Edit:
Are you adding btPlay to the stage or display hierarchy?
eg.
btPlay = new mcButtonPlay(this,"ClickMe",GameImage);
this.addChild(btPlay);
Managed to fix it by swapping the super and add child logic around:
public class mcButtonPlay extends navigationButtonHandler {
public function mcButtonPlay(Parent:MovieClip,Text:String,GameImage:BitmapData) {
if (GameImage != null) {
var ImageBitMap:Bitmap = new Bitmap(GameImage);
this.addChild(ImageBitMap); // * * * This doesn’t show
Parent.addChild(ImageBitMap); // Works just to test the image
}
super(Text);
}
}
No idea why though!
Related
I am making a program using the amazing libGDX+scene2d API and I structured it as follows:
I have a single MyGame instance, holding a single PolygonSpriteBatch instance.
There is an abstract MyScreen class, holding a MyStage class (see below)
Then there are lots of different screen classes that inherit from MyScreen, and instantiate each other at will.
(in all cases, removing the "My" gives you the name of the respective library class that it extends)
This model worked fine, until I encountered some problems to perform actions between screens using the Action system. I decided then that it would be a good idea to have a single OmnipresentActor belonging to MyGame that, as the name says, is present in every scene. So I modified MyStage to look more or less like this:
public class MyStage extends Stage {
public MyStage(MyGame g) {
super(new FitViewport(MyGame.WIDTH, MyGame.HEIGHT), g.batch);
addActor(game.omnipresentInvisibleActor);
}
#Override
public void clear() {
unfocusAll();
getRoot().clearActions();
getRoot().clearListeners();
removeActorsButNotListenersNorActions();
}
public void removeActorsButNotListenersNorActions() {
for (Actor a : getActors()) if (a.getClass()!= OmnipresentInvisibleActor.class) a.remove();
}
It followed a painful debugging phase, until I found out the following:
public PresentationScreen(MyGame g) {
// super() call and other irrelevant/already debugged code
System.out.println("PRINT_BEFORE: "+ stage.getActors().toString()); // OmnipresentActor is there
mainMenuScreen = new MainMenuScreen(game);
System.out.println("PRINT_AFTER: "+ stage.getActors().toString()); // OmnipresentActor is not there anymore, but was added to the mainMenuScreen
the "PRINT_BEFORE" statement shows that the stage holds the omnipresentActor. In "PRINT_AFTER" it isn't there anymore, whereas mainMenuScreen is indeed holding it. So my question, now more precise:
does scene2d prevent this to happen, or am I doing something wrong here?
Answers much appreciated! Cheers
An actor can only be a member of one stage: Thanks to #Tenfour04 for confirming that. The explanation is quite clear after doing a little research:
Stage.addActor() looks like this:
(here the github code of Stage.java)
/** Adds an actor to the root of the stage.
* #see Group#addActor(Actor) */
public void addActor (Actor actor) {
root.addActor(actor);
}
whereas root is simply initialized as a group in the Stage constructor: root = new Group();.
And Group.addActor() looks like this:
(here the github code of Group.java)
/** Adds an actor as a child of this group. The actor is first removed from its parent group, if any. */
public void addActor (Actor actor) {
if (actor.parent != null) actor.parent.removeActor(actor, false);
children.add(actor);
actor.setParent(this);
actor.setStage(getStage());
childrenChanged();
}
So in the tree first lines is the answer: when creating the new stage, if the actor to add already has a parent, it is removed from its current parent. So, There are two possible solutions to the problem I enounced:
SOLUTION 1: Override addActor removing the if statement, or any other alteration of the library, which I'm not sure if it would work. I rather think this could be very problematic, for instance it could prevent the stages from disposing correctly
SOLUTION 2: Change the design so you don't need an omnipresent actor, nor changing/reimplementing the libraries. For the moment this is what I've done based on this answer, it isn't very clean but it works so far:
1) In the MyScreen class added the following fields:
private boolean watchingTemp;
private Actor watchActorTemp;
private Action actionTemp;
2) Then added this method:
public void addActionOnStageAfterActorEndsHisActions(Actor actor, Action action) {
watchActorTemp = actor;
actionTemp = action;
watchingTemp = true;
}
3) then in the render method, I added the following:
if (watchingTemp && !watchActorTemp.hasActions()) {
watchingTemp = false;
stage.addAction(actionTemp);
}
4) finally, when wishing to perform an action at a screen transition (and eventually disposing the first one), you can do something like this: I use something similar when clicking on a door between screens
public void movePlayerTHENgotoNewScreen(float xPos, float yPos, whatever else...) {
game.player.walkToAnyPoint(xPos, yPos);
yourFavoriteScreen.addActionOnStageAfterActorEndsHisActions(game.player, gotoNewScreen(wathever else...));
}
Hope it helps!
My goal is:
define a subClass of Sprite called Ship
use an event at runtime to call a function within this new class
It seems that I've figured out how to create my Ship class using a package in a linked .as file. But I can't seem to access the function within that class. Can anyone see what I'm doing wrong?
var ShipMc:Ship = new Ship();
addChild(ShipMc);// This successfully adds an instance, so I know the class is working.
addEventListener(MouseEvent.CLICK, ShipMc.addShip);//But this doesn't seem to run the function
This code works fine for instantiating a Sprite, but the code in the Ship.as file, specifically the function, is not working. No runtime errors, but nothing traced to the output window, either.
package
{
import flash.display.Sprite
public class Ship extends Sprite
{
public function addShip():void
{
trace("running addShip function")
}
}
}
The last time a coded anything in flash it was AS2!
I'll just mention that I've tried using addShip():void and just addShip(). Same response with both. It should be with :void, right? Anyway, the fact that neither one throws, tells me that this section of code isn't even getting read, I think.
Any help is much appreciated! Pulling my hair out.
Your code is not working because it contains some problems, so let's see that.
You should know that you are attaching the MouseEvent.CLICK event listener to the main timeline which didn't contain any clickable object yet now (it's empty), so let's start by adding something to your Ship class to avoid that :
public class Ship extends Sprite
{
// the constructor of your class, called when you instantiate this class
public function Ship()
{
// this code will draw an orange square 100*100px at (0, 0)
graphics.beginFill(0xff9900);
graphics.drawRect(0, 0, 100, 100);
graphics.endFill();
}
public function addShip():void
{
trace("addShip function run");
}
}
N.B: You can attach the MouseEvent.CLICK event listener to the stage, which will work even if you have nothing in the stage.
Now, if you test your app, you'll get an clickable orange square at the top left corner of your stage, but the compiler will fire an error (ArgumentError) because it's waiting for a listener function (the Ship.addShip() function here) which accept an MouseEvent object.
So to avoid that error, your Ship.addShip() function can be like this for example :
public function addShip(e:MouseEvent):void
{
trace("addShip function run");
}
Then your code should work.
You can also simplify things by using another listener function in your main code which can call the Ship.addShip() function, like this for example :
var ShipMc:Ship = new Ship();
addChild(ShipMc);
addEventListener(MouseEvent.CLICK, onMouseClick);
function onMouseClick(e:MouseEvent): void
{
ShipMc.addShip();
}
For more about all that, you can take a look on AS3 fundamentals where you can find all what you need to know about AS3.
Hope that can help.
here is my problem. In my document class TowerDefenseGame.as, I defined a variable Turrent1Flag:
package
{
import flash.display.MovieClip;
import flash.events.*;
import flash.display.Sprite;
import flash.display.Shape;
import flash.text.TextField;
import flash.text.TextFormat;
import flash.text.TextFieldType;
public class TowerDefenseGame extends MovieClip
{
public var Turrent1Flag==0;
}
public function TowerDefenseGame()
{
......
}
Now, in another class Turrent1Button.as, I need to create a mouse click event, by which the Turrent1Flag is set to 1:
package
{
import flash.display.MovieClip;
import flash.events.*;
import flash.display.Sprite;
import TowerDefenseGame;
public class TurretButton1 extends MovieClip
{
public var ButtonBase:Sprite=new Sprite();
public var TurretBase:Sprite=new Sprite();
public var Gun:Sprite=new Sprite();
public function TurretButton1()
{
......
this.addEventListener(MouseEvent.CLICK, MouseClick);
}
public function MouseClick(event:MouseEvent):void
{
MovieClip(root).Turret1Flag = 1;
}
Well, this does not work. I am using Adobe flash cs6 and it says the value cannot be accessed. Someone know how to do this?
try this:
private static var _instance:TowerDefenseGame;
public static function get instance():TowerDefenseGame { return _instance; }
public function TowerDefenseGame()
{
_instance = this;
}
public function MouseClick(event:MouseEvent):void
{
TowerDefenseGame.instance.Turret1Flag = 1;
}
So, to start out, AS3 makes it difficult to so what you've been used to doing in AS2 on purpose, to allow for better Object Oriented practices. When you maintain high and tight walls between Classes, it becomes easier to change Class A without having any effect whatsoever on Class B. Class B only knows about the doors and windows that are the "official" ways into the house of Class A, so it doesn't matter if you move the couch. You also make it extremely easy to replace Class A with Class C that has similar doors and windows.
When you reach through the walls by introducing global state, you can't replace Class B with Class C without changing Class A, because Class A has a direct reference to Class B and knows exactly where the couch is.
One way to handle this is through Inversion of Control (IoC). So, for our house, the couch might be supplied from outside and whatever component supplied it might keep a reference to it, so it would be able to access the couch no matter where in the house it went. So, you might choose to create your TurretButton and pass that into whoever owns that, while your TowerDefenseGame keeps a reference to it and listens directly to it, changing its own flag in response to the click.
Looking at your code, you probably don't need to go that far, because I don't see any sign that your TurretButton is actually nested. In that case, you can listen directly to it, whether you're creating it on the stage or creating it through code (which I'm not a fan of). If you're using the stage in the IDE and it exists on the stage, then just create a public variable of type TurretButton (or you could probably use SimpleButton since you no longer have need for a special Class here based on the code you've shown). That instance will be available in the constructor of your TowerDefenseGame. Just add your event listener to it, and then the listener and the variable you want to change are in the same scope. Ergo, the problem you were trying to solve never existed--you were simply looking at the problem from a perspective that overcomplicated things.
If, in fact, your code is nested in a way that's not shown, you can use ActionScript 3's event system, which is fabulous, to handle the issue without introducing direct coupling and without having to create the button through code and push it down to where it's used. One way is to just listen for any mouse click (since that is a bubbling event) and look to see what was clicked. Another solution is to generate a custom event from the button that you can then listen to from the top level to change the flag. That would look something like:
package view.button {
public class TurretButton extends MovieClip {
public function TurretButton() {
super();
mouseChildren = false;
addEventListener(MouseEvent.CLICK, broadcastTurretEvent);
}
protected function broadcastTurretEvent(e:Event):void {
dispatchEvent(new Event('turretClicked', true));//the true parameter makes it bubble
}
}
}
Then your tower Class would look like
package {
public class TowerDefenseGame extends MovieClip {
//the fact that you're calling it Turret1Flag suggests you're going to have more than 1
protected var turretFlags:Array /*of Boolean*/ = [false, false];
//your turret button instances
//doesn't show nesting, this is just to indicate that
//these are named instances so you know how what they're called
//they could be nested at any level
public var turret1:TurretButton;
public var turret2:TurretButton;
//...etc.
public function TowerDefenseGame() {
super();
addEventListener('turretClicked', onTurretClicked);
}
protected function onTurretClicked(e:Event):void {
//you can also just extract the number and do the math
//to get the correct array index
switch(e.target.name) {
case 'turret1':
turretFlags[0] = !turretFlags[0];
break;
case 'turret2':
turretFlags[1] = !turretFlags[1];
break;
}
}
}
}
Note how well this scales. You don't have to have a different Class for each button to change each separate flag. It's also easy to add more buttons without a whole lot of code changes. You could take this solution further and create a custom event that has a property that says which button was clicked, and you could supply the value to use to that for the button through dependency injection, etc.
I also made the assumption in my code that flags should be boolean and that they're turning on with the first click and off with the second click, etc. You could take the same idea and change it to, for example, increment with every click. I suspect you don't actually want to do what your code was showing and just turn it on with the first click and just leave it on forever.
Another note is that if you think you might want to code in AS3 over the longer term, you should probably learn the coding conventions that are used in AS3. One of these is that Class names start with a capital letter, but properties and methods do not.
It's probably not a great habit to get into for everything, but a static variable looks like it would work here.
public class TowerDefenseGame extends MovieClip
{
public static var Turrent1Flag = 0;
}
In Turrent1Button.as:
public function MouseClick(event:MouseEvent):void
{
TowerDefenseGame.Turret1Flag = 1;
}
I have been struggling with the following for a couple of hours now, how do you call a custom class from another class if you do not extend that class for example.
I have on my main Base class a timer event, Base.myTimer.addEventListener(TimerEvent.TIMER, processTime) - Base class
Then I remove the method later in the code Base.mytimer.removeEventListener(TimerEvent.TIMER, processTime. - Base class
I have a button (Btn class) that when its done processing I want to call that method again, but I can't get it to work because the method does not exist in the button class but on the Base class so flash obviously gives me the error processTime is not defined.
For example now I want to re-instantiate the event listener from within the button, so I have
Base.myTimer.addEventListener(TimerEvent.TIMER, processTime);
or this.parent.parent["myTimer"].addEventListener()
myTimer is a static Timer in Base class.
I can make a normal dispatchEvent if its not a custom method for example Base.myTimer.dispatchEvent(new TimerEvent(TimerEvent.TIMER)).
The examples I have seen so far have not resolved my issue. Any help would be appreciated.
Looks like the button class is part of the child tree of the Base class. In this case, you can just do a dispatchEvent from the button class when it is clicked
dispatchEvent(new Event("AddListenerAgain", true));
In the Base class, you must be having access to the button class already, hence you can say:
button.addEventListener("AddListenerAgain", addListener);
Then in the Base class
private function addListener(e:Event) : void {
myTimer.addEventListener(TimerEvent.TIMER, processTime);
}
In this example, I have dispatched and listened for raw strings. This is not a recommended practice. You must read on how to dispatch custom events to do it correctly.
You could pass a reference to an instance of Base class into your Button instance.
// Button class
package {
import Base;
// Other imports...
public class Button {
public function Button(base:Base):void {
// processTime and myTimer must be public.
// I put this line in the constructor for brevity, but if you stored base
// in an instance variable, you could put this anywhere in the button
// class.
Base.myTimer.addEventListener(TimerEvent.TIMER, base.processTime)
}
}
}
// Create button like this.
var button:Button = new Button(base);
// Or if button is created inside of Base
var button:Button = new Button(this);
Even better would be to create two methods in the Base class, for adding and removing the listeners, and make myTimer and processTime private:
public class Base {
public function addTimerListeners():void {
myTimer.addEventListener(TimerEvent.TIMER, processTime)
}
public function removeTimerListeners():void {
myTimer.removeEventListener(TimerEvent.TIMER, processTime)
}
}
Then you can call these two methods from outside of the class. This keeps the inner workings of your class more hidden. If you decided you wanted to change myTimer to a instance variable instead of static, you wouldn't have to make any changes to code outside of your Base class. This is called encapsulation and is a good practice.
I have a movie clip with an external class attached.
here is the MC code (I've shorten it only for the relevant part...)
package {
//all the imports here...
public class mc_masterChapter extends MovieClip {
public function mc_masterChapter() {
trace (picFile,strChapTitle);
}
//Properties
public var picFile:String;
public var strChapTitle:String;
}
}
In the main class file I'm adding this object to stage using addChild:
var masterChapter:mc_masterChapter = new mc_masterChapter;
masterChapter.picFile = "pic_Chap1.jpg";
masterChapter.strChapTitle = "ABCD:
addChildAt(masterChapter,1);
now, the trace in the MC class code gives nulls to both parametes but if i put a trace inside the MC timeline (instead of the attached class code), it gives the right value!
how can I access the values from the MC class itself without getting nuls?
Thank you.
It works! Let me explain:
var masterChapter:mc_masterChapter = new mc_masterChapter; // Calls class constuctor
// so calls trace() too!
// You will get null null
masterChapter.picFile = "pic_Chap1.jpg"; // Assign the variables
masterChapter.strChapTitle = "ABCD"; // so they can be read
trace(masterChapter.picFile, masterChapter.strChapTitle); // Should trace pic_Chap1.jpg ABCD
If you add the following method to your class:
public function test():void {
trace(picFile, strChapTitle);
}
Then call masterChapter.test() it will successfully trace those two properties. So yes, the class can read its properties.
Make the var you use in your main class public static vars.
OK!
I solved the mystery.
I put two traces. one in the main MC class saying "hey, I'm inside the MC - the picFile="
and one in the put Function saying "I'm putting this file into picFile:"
well this is what I've got:
hey, I'm inside the MC - the picFile=null
I'm putting this file into picFile:image.jpg
got it!?! at the moment I asked him to give birth to an instance of the MC (even before putting it on stage - just defining the object (with this line:)
var masterChapter:mc_masterChapter = new mc_masterChapter;
it allready run the class, so of course that in this stage the parameters were not defined allready and were null.
the definition code came right after that line (in the main.as)
masterChapter.pic="pic_Chap1.jpg";
so what I did, was to move all the code from the main class of the MC object to a public function inside the same package called init(). Then I called this function manually from the parent main class.
By that I can decide when to call it (after I declare all the parameters of course).
That's it.
god is hiding in the small details : )
tnx for all the helpers.
Possibly a better solution would be to use a getter/setter pair, so you can know at the exact moment the properties are set:
protected var _picFile:String:
public function get picFile():String {
return _picFile;
}
public function set picFile(value:String):void {
if (value != _picFile) {
_picFile=value;
trace('picFile set to', _picFile);
}
}