I have set the instance name of MovieClip to char and when i try to compile this code i get 2 Errors:
package com.game
{
import flash.display.MovieClip;
import flash.events.*;
public class game extends MovieClip
{
var gravity = 0.8;
var velocity = 0;
char.addEventListener(Event.ENTER_FRAME,isHitted);
function isHitted(event:Event):void
{
if (char.hitTestObject(level1))
{
velocity++;
char.y -= gravity+velocity;
}
else
{
}
}
Errors:
.../game.as, Line 13 1120: Access of undefined property char.
../game.as, Line 13 1120: Access of undefined property isHitted.
First off, it sounds like this class definition is the definition for the instance you are referring to, if it is, you should use 'this' instead of 'char'
Also, you typically do not specify method calls like:
char.addEventListener(Event.ENTER_FRAME,isHitted);
outside of methods when declaring a class. Instead, that line of code should exist inside of a constructor or a method that is called during the instantiation of the MovieClip.
You need to make 'char' accessible to 'game' before being able to use it.
One way is to pass 'char' as parameter when you instantiate 'game'.
Two ways of doing this are described in the answer of #lee-burrows in Access caller object when using composition in AS3
Related
I'm writing a program using Main.as, that needs to listen to a function (getColor) in another class file (GetColor.as). I have the following in GetColor.as:
public class GetColor
{
public function getColor(event:MouseEvent):void
{
//doing stuff here
this.dispatchEvent(new Event("changeColor") );
}
}
and then in Main.as I have:
var getPicColor:GetColor = new GetColor();
getPicColor.addEventListener("changeColor",changeColorNow);
function changeColorNow(e:Event):void
{
//do stuff here
}
However, I am getting an error:
1061: Call to a possibly undefined method dispatchEvent through a reference
with static type GetColor.
What does this mean? I have nothing declared as static. Am I supposed to create an instance of dispatchEvent(), as opposed to using "this"?
You cannot dispatch events with a class that (implicitly) extends Object -> that's why you are getting there error -> where is "dispatchEvent()" method coming from? Where is it inherited from? (answer: it is not!)
Your GetColor class (horrible name there! :) ) must either extend a display object - which in your case it not really the correct solution, extend EventDispatcher or implement IEventDispatcher.
Then you can use the method dispatchEvent.
In my class, I tried using this line:
trace(flash.utils.getQualifiedClassName(getQualifiedClassName(TempButton)))
However, I get this error:
"1120: Access of undefined property flash."
Can someone help me solve this issue? The code is in an AS file under the class Main that extends as a MovieClip.
You probably have forgotten to import "getQualifiedClassName" class. This code should work:
// remember to import class(es)
import flash.utils.getQualifiedClassName;
public class ... {
// constructor
public function ... () {
// you don't have to use that "flash.utils." before you call the function,
// but you can do that too, if you want
trace(flash.utils.getQualifiedClassName(getQualifiedClassName(TempButton)));
}
}
I found a quite strange problem while making two classes in AS3. Let's call them ParentClass and ChildClass. In order to make both of them you need a Sprite object, then the ParentClass makes it visible in the stage. ChildClass inherits the ParentClass, too.
ParentClass.as:
package myStudio.basic {
import flash.display.MovieClip;
import flash.display.Sprite;
public dynamic class ParentClass extends MovieClip {
public function ParentClass(mc:Sprite=null) {
addChild(mc);
}
}
}
ChildClass.as:
package myStudio.containers {
import myStudio.basic.ParentClass;
import flash.display.MovieClip;
import flash.display.Sprite;
public class ChildClass extends ParentClass {
public function ChildClass(mc:Sprite=null) {
addChild(mc);
}
}
}
Then, I write this code on Frame 1, Layer Actions of the FLA file:
var mc:MovieClip = new childMC;
var vig:ChildClass = new ChildClass(mc);
addChild(vig);
However, I got run-time error #2007:
TypeError: Error #2007: The value of the parameter child must not be null.
at flash.display::DisplayObjectContainer/addChild()
at myStudio.basic::ParentClass()
at myStudio.containers::ChildClass()
at myStudioComicAnimator_fla::MainTimeline/frame1()
I tried overriding the ChildClass constructor function, but it still doesn't work.
So here's my question: Is there another workaround to solve this problem?
The reason for that is that you are not calling super. You can check what's happening in the error stack (down to top):
you instantiate ChildClass, and you pass the previously created childMC to the constructor
ChildClass extends ParentClass, so when instantiated it always calls the constructor
the constructor of ParentClass tries to add something as a child
The problem is that you cannot add null as a child. But because the constructor is called internally, there is no param that is being passed to it. so mc variable is always null. But as we said - null cannot be added.
Use the super by yourself:
public function ChildClass(mc:Sprite=null) {
super(mc);
}
This way the ParentClass will get reference to the mc object and will be able to add it.
Another option is not to use addChild in the ParentClass, but only in ChildClass. Then it doesn't matter if you pass anything to super, or even if you are calling super at all.
Edit: I forgot to say that this is not a bug, but a standard behavior and works exactly like it should work. The reason for this is that each class can have a whole different override of the constructor. It can take more or less parameters, so the chain for calling parent's constructor is your job to handle.
So I have this superclass grid class, and a subclass of the grid class named GrassTile1, GrassTile2, etc... all of the instance of the subclasses are stored in an array. How am I suppose to convert the instance of subclass to its superclass referencing to the array?
private var backgroundGrid = []; //the array which the grids are stored in, in the main class.
public class Grid extends MovieClip
{
protected var node :PathfindNode; //the variable I wish to access, from an instance of subclass.
public function Grid(){
node = new PathfindNode();
}
}
public class GrassTile1 extends Grid { //every subclass of Grid will extends Grid
public function GrassTile1() {
// constructor code
}
}
function getBackgroundGrid(i:int,j:int):Grid{ //in the main class
return Grid(backgroundGrid[i][j]); // this line gives me an error
}
TypeError: Error #1034: Type Coercion failed: cannot convert GrassTile1#2905d5f1 to Grid.
I've tried accessing backgroundGrid[i][j].node and other ways to work around that I could think of and failed. Any Idea?
Try :
return backgroundGrid[i][j] as Grid;
Personally, Grid seems like a bad class name to use. I think Tile makes more sense, as that GrassTile1 is not a grid as I logically understand a grid. A grid might contain a collection of tiles, so doesn't sound logical to use that as a class name for tiles.
Also, where is the line where you actually call the getBackgroundGrid method ? You should try casting there, as opposed to in that method. I believe that will solve the problem.
I can't verify the line throwing the error, so we are assuming that it's the return statement. But, it could be on the other side where you are calling getBackgroundGrid.
UPDATE : I have tried a .fla using what you are describing and it works just fine, I get no error. Which is why I'm thinking we are missing something here and maybe the definition of the class is not being used. Can you put a trace in your constructors to verify what you expect is actually happening ?
So I have a method that takes in a String and then is suppose to set the dynamic textbox on a button to said String.
public function setText(caption:String) {
this.btext.text = caption;
}
I really don't understand why this method is producing a 1119 error.
Access of a possibly undefined property btext through a reference with static type Button.as
The instance name of the Dynamic Textbox is btext and I have tried deleting the textbox and making a new one however this still produces a 1119 error. I also read on another stack question that trying this['btext'].text = caption; which gave me plenty of runtime errors.
Basically what am I doing wrong?
Thank you for any help.
EDIT
Here is the code I am using, and I create an instance of button add it to the stage and store it in an array with this code.
Code to create button
this.buttonArray.push(this.addChild(weaponButton));
Button.as
package {
import flash.display.MovieClip;
import flash.filters.*;
public class Button extends MovieClip {
public function Button() {
}
public function setPosition(xpos:int, ypos:int) {
this.x = xpos;
this.y = ypos;
}
public function setScale(xScale:Number, yScale:Number) {
this.scaleX = xScale;
this.scaleY = yScale;
}
public function addDropShadow():Array {
var dropShadow:DropShadowFilter = new DropShadowFilter(2,45,0, 1,4,4,1,1,true);
return [dropShadow];
}
public function removeDropShadow():Array {
return null;
}
public function setText(caption:String) {
this.btext.text = caption;
}
}
}
As you have stated btext is an instance name of an object. Here is where I assume btext is an object you created in your library.
In your class you are doing 2 things wrong. So lets examine your method.
public function setText(caption:String) {
this.btext.text = caption;
}
The first thing wrong is you are using "this". "this" is a reference to the current instance of the class you are in. And you are saying btext is a property on said instance. Which as I am assuming it is not because you defined btext as an object in your library. This will give you the property is undefined error you are gettting.
Now the second issue at hand is you are about to ask "OK how do I reference btext in my class then". What you need to know is that only objects added to the display list IE:stage can access objects via the stage.
You can do this 3 ways.
The first way is to pass a reference to the button into the class and store it as a property of the class.
The second way is to add your class to stage and in the class listen to the addedToStage event. At that time you can then access the object.
MovieClip(root)["btext"].text
The first 2 methods are not good practice since btext is not apart of the class and a general rule of thumb would be to encapsulate your class.
To make this work what you could do is have your class assign the value to a property in your class then fire an event and make the parent of this class listen to that event then just grab the value and assign.
Here is some suggested reading
I think the variable btext doesn't exist at all, or is it inherited from Movieclip?