I am very familiar with JavaScript and am now having a play with Flex for the first time. Obviously it's a strange felling as JavaScript and ActionScript are as they would say here in Southeast Asia "same same but different". The one thing that's getting to me (as with all static languages) is the verbosity. Are there any shorthand tricks that can slim down the following common code:
package com.mate.extensions {
public class HTTPResponse
{
public var data:String;
public var responseURL:String;
public var responseHeaders:Array:
public var status:Number;
public function HTTPResponse(data:String, responseURL:String, responseHeaders:Array, status:Number):void {
this.data = data;
this.responseURL = responseURL;
this.responseHeaders = responseHeaders;
this.status = status;
}
}
}
I guess it's a matter of what you're used to; I came to AS3 from Java, and to me, that code looks perfectly reasonable. :)
Honestly, I don't think you can trim this down substantially without taking a big hit in either readability or functionality. (Of course, now that I've said that, I look forward to somebody smarter than me proving me wrong.) In fact, it may actually be too terse; making your internal fields publicly accessible is generally considered bad form and an invitation to headaches down the road. Though one of the lovely things about AS3 is that because of how getters and setters are handled, you can switch from public fields to accessor-controlled private fields without needing to make any changes to code that uses this object.
If your concern is verbosity versus coding standards, you could throw the whole HTTPResponse class away and replace it with an Object.
var httpResponse:Object = { data: data, responseURL: responseURL, responseHeaders: responseHeaders, status: status };
But in that case you would miss the compile time types checking and code reusability.
The great thing with ActionScript is that it's same same & different.
Related
How to write test case for this function in a binary search tree ?
void insert(String key){
root=insertRec(root,key);
}
Your method does something. It obviously changes the state of the object by inserting a rec(ord?) and somehow re-evaluating what the root is. So, to test it, you should somehow be able to determine the new state, for example...
public void insert_should_create_new_record_and_set_root() {
assertThat( myObject.getRec( originalRoot) ).isNull();
Object originalRoot = myObject.getRoot();
myObject.insert("xyz");
assertThat( myObject.getRec( originalRoot) ).isEqualTo( "xyz"); // using AssertJ style here
assertThat( myObject.getRoot().value() ).isNotEqualTo( originalRoot );
}
If, on the other hand, you have no way to check the state from the outside, then you'll have a problem. But somehow your class has to communicate to the outside, hasn't it? If you really think that you cannot check the new state, then you'll have to provide more code of this class, as this answer is, of course, very general (which means "guessing", here).
When running swfs through decompilers (my own swfs, not somebody else's), I've noticed a lot of mention of certain variables:
_loc_1
_loc_2
_loc_3
.
.
.
_loc_n
As in the following example:
private function templateFilterFunction(param1) : Boolean
{
var _loc_2:* = false;
if (filterFunction != null)
{
_loc_2 = filterFunction(param1, typedText);
}
return _loc_2;
}
Alright, so these are apparently just normal variables then, right? And they may have had more descriptive names in the original AS3 code, but that's been lost in the bytecode, and now we have the same variables as before, just with non-descript names, right?
Not exactly. For instance:
package
{
public class SomeClass extends Object
{
public var var1:Number;
public var var2:Number;
public var var3:Number;
public function SomeClass(param1:Number, param2:Number, param3:Number)
{
if (!_loc_5)
{
if (!_loc_4)
{
var3 = param1;
if (!_loc_4)
{
var1 = param2;
}
}
}
var2 = param3;
return;
}// end function
}
}
These aren't declared. But they're not exactly members of Object either, and I've never seen them outside of a swf decompilation. What are they then? Thanks.
Not sure about that particular piece of code, but the decompilers I've used (as far as I remember) all call the local variables loc_n, local_n or something like that.
I think you already know why. Local variables are created and pushed onto the execution stack; they are not referenced from outside the local scope and since they are not callable by name, their names are just whipped off the bytecode. (The object pointed by the variable could be allocated on the heap and live outside the scope of the function, however, but that's not the point here).
Now, another thing you might be aware of is that some bytecode generated by the compiler just doesn't traslate to actionscript code. There are things that can be done in bytecode that are not really possible in AS code; an example, off the top of my head: the "dup" opcode (duplicates a value and pushes it onto the stack). There are others (jumps, noops, etc). Reversing this to the original source code is sometimes not possible.
There are other interesting cases such as loops. You may notice that a particular decompiler tends to generate "for loops" (or "while loops") regardless of whether the source code had a for or a while. That's because loops are a higher level construct that are usually implemented in bytcode as conditional jumps. If you want to reverse the bytecode to AS code, you just have to pick a flavor because the loop (as an AS construct) is just not there.
That said, I've seen some decompilers (can't remember which one now) generating invalid or non-sensical source code. To me, that's the case in the example you post. I may be wrong but it seems like the _loc_5 and _loc_4 vars are just gibberish and the original code must be something like:
public function SomeClass(param1:Number, param2:Number, param3:Number):void
{
var var3:Number = param1;
var var1:Number = param2;
var var2:Number = param3;
}
Is one of these particularly more effiicient than the other?
1:
Within Class A:
var b:B = new B();
b.addEventListener(B.TYPE1, onType1);
b.addEventListener(B.TYPE2, onType2);
b.addEventListener(B.TYPE3, onType3);
Within Class B:
dispatchEvent(new Event(TYPE1));
.
.
.
dispatchEvent(new Event(TYPE2));
.
.
.
dispatchEvent(new Event(TYPE3));
2:
Within Class A:
var b:B = new B();
b.addEventListener(CEvent.TYPE, onCEvent);
.
.
.
private function onCEvent(pEvent:CEvent):void
{
switch (pEvent.code)
{
case B.TYPE1:
onType1();
break;
case B.TYPE2:
onType2();
break;
case B.TYPE3:
onType3();
}
}
Within Class B:
dispatchEvent(new CEvent(TYPE1));
.
.
.
dispatchEvent(new CEvent(TYPE2));
.
.
.
dispatchEvent(new CEvent(TYPE3));
Class CEvent:
public class CEvent extends Event
{
public static const TYPE:String = "cEvent";
private var m_strCode:String;
public function get code():String
{
return m_strCode;
}
public function CEvent(pCode:String, bubbles:Boolean=false,
cancelable:Boolean=false)
{
super(TYPE, bubbles, cancelable);
m_strCode = pCode;
}
override public function clone():Event
{
return new CEvent(m_strCode, bubbles, cancelable);
}
}
My understanding has been that #2 will be a lot more time-efficient than #1, and right now, I'm needing to really work on finding various ways to make my code run almost as fast possible (almost as in the context of video game programming). Earlier on I wasn't using the second technique though, so there's gonna be a lot of work going into consolidating the different types strewn across my code. I need to ask first and make sure that this is halfway reasonable. Thanks!
EDIT
Something I came to realize a while after posting this was that ActionScript 3's event model is criticized for inefficiency largely over the fact that a brand new object is created each time an event is created. Creating objects can be a slightly bulky process, in and of itself, so an event model that is based on creating brand new objects over and over again is liable to be fairly inefficient as a direct result of that.
At the time I wrote this question, I wasn't aware this was the source of cricism, or of the fact that object creation was slow, and putting it in that light, neither one of the approaches above would really do much to get around that issue. (Approach 2 would probably be ultimately worse.) I don't want to put that down as an answer, but I do want that bit of context to be put down on this thread.
Are you sure you need to optimize it?
The difference will be likely negligible whichever way.
Your switch is a half-baked ad hoc implementation of what EventDispatcher is meant to do. You are trying to invent a bicycle, and it is likely to have square wheels. This is the job of EventDispatcher to provide an instrument of adding or removing handlers, managing what handlers get called and when etc. If you are dissatisfied with that how EventDispatcher works (why?) - the way to address it is to either extend and change something within it, or write an alternative implementation. Trying to "fix" it locally for some particular case of a handful of functions will bring disorder into your code, making it less maintainable and, as it stands now, more verbose.
I am using Box2D for the first time seriously in a medium sized Flash Game that I am working on. My current experience with Box2D is limited to creating a world, bodies and adding those bodies to the world in a functional manner.
I'm finding it easy enough to integrate Box2D into my game environment, maintaining well-written code and have completed a few tutorials that walk through dealing with collisions. The issue that I'm facing now is that my game will have many bodies, each interacting with other bodies in different ways, and I'm finding it hard to write my own b2ContactListener subclass without it getting extremely messy.
Based off a tutorial I used, I have created my own subclass of b2ContactListener and added an override of the BeginContact() method. The argument that BeginContact() receives when it is called will reference an instance of b2Contact, through which I can access two b2Fixture instances (the two instances that have collided). I am then able to access the b2Body instance associated with each of those b2Fixtures.
Problem: Currently I have a roundabout way of finding out what two things collided (i.e. whether they're a wall and a missile, or the player and a tree, etc) which uses GetUserData() and looks like this as an example:
var f1Player:Boolean = contact.GetFixtureA().GetBody().GetUserData() is Player
var f2Player:Boolean = contact.GetFixtureB().GetBody().GetUserData() is Player
var f1Tree:Boolean = contact.GetFixtureA().GetBody().GetUserData() is Tree
var f2Tree:Boolean = contact.GetFixtureB().GetBody().GetUserData() is Tree
// ... continutes with all possible combinations.
// Example of managing a collision:
if(f1Player && f2Tree)
{
// Player (FixtureA) and Tree (FixtureB)
}
if(f2Player && f1Tree)
{
// Player (FixtureB) and Tree (FixtureA)
}
As you can see, this is going to end up extremely long and unmanageable. I also have to write each set of actions to perform twice to cater for a certain element being FixtureA or FixtureB, or vice versa (obviously in the form of a function call with the parameters swapped around rather than literally re-written).
This is clearly not the correct approach, but I haven't been able to locate resources that more thoroughly explain collision detection management.
Does anyone have experience with collision detection management using Box2D that they can share? Also, is using SetUserData( entityThatOwnsTheBody ); the correct way to be using that method?
Yeah, it's a bit of a nuisance indeed. Actually I think the way you have it is quite typical.
fwiw Box2D itself has to deal with a similar problem when testing whether fixtures overlap. There are a bunch of functions such as b2CollideCircles, b2CollidePolygonAndCircle, b2CollidePolygons etc, and when two fixtures come near each other the engine chooses which of these functions should be used.
It does this by putting the function pointers in a 2-dimensional array, then looks up the appropriate function in this array by using the two shape types as index. See the first three functions in b2Contact.cpp for details.
Of course, if you can't pass around function references like this in AS3 then I guess this answer doesn't help much, but I thought I would post anyway as C/C++/JS users might come by.
I've used c++ version of Box2d, but I think the same approach will work in actionscript. I create a class Object, that contain a b2Body *_body pointer and a pointer to graphical representation. _body's UserData was set to point to Object *. class Object had the following methods:
virtual bool acceptsContacts ();
virtual void onContactBegin (const ContactData &data);
virtual void onContactEnded (const ContactData &data);
virtual void onContactPreSolve (const ContactData &data);
virtual void onContactPostSolve (const ContactData &data);
When collision was detected in b2ContactListener subclass, it checked if collided bodies have user data. If so, it casted their user data to Object* and if any of the collided objects accepted contacts - it created ContactData ( a class with all required information about collision) and put it in it's internal list to deliver later.
When b2World::update method returned, ContactListener delivers all contact information to objects to process. Delivery was delayed in order you could create new bodies, joints and so on, right when processing collision (which is not allowed while update is executing)
Also you must notify ContactListener (just put a pointer to it inside ContactData) if one of the collided body was deleted during collision processing, so it can invalidate appropriate contacts and not deliver them
I've come up with something much nicer than the original.
Firstly, I just have my Being class (which owns a b2Body) set itself as its bodies' UserData. This class will also contain an onContact() method and look similar to the below:
public class Being
{
private var _body:b2Body;
public function Being()
{
// Define the body here.
// ...
_body.SetUserData(this);
}
public function onCollision(being:Being = null):void
{
//
}
}
Then in my own b2ContactListener implementation, I simply pass the colliding Being (or null, if there is no Being assigned to the colliding b2Body's UserData) to the opposing Being's onCollision():
override public function BeginContact(contact:b2Contact):void
{
var bodyA:b2Body = contact.GetFixtureA().GetBody();
var bodyB:b2Body = contact.GetFixtureB().GetBody();
var beingA:Being = bodyA.GetUserData() as Being || null;
var beingB:Being = bodyB.GetUserData() as Being || null;
beingA && beingA.onCollision(beingB);
beingB && beingB.onCollision(beingA);
}
And finally in each of my subclasses of Being, I can easily prepare logic appropriate for a collision between other Beings of a certain type:
class Zombie extends Being
{
override public function onCollision(being:Being = null):void
{
if(being && being is Bullet)
{
// Damage this Zombie and remove the bullet.
// ...
}
}
}
UPDATE: OK I am about ready to give up on Pacakages and classes. No answers coming. Not sure what to do. I tried to make the question easier and made a new post but I was down voted for it. as3 calling a function in another class
I am TOTALLY NEW to using PACKAGES and CLASSES. I am finally converting over from the timeline after having so many issues. Please be patient with my lack of knowledge. I need to know how to call a function in the child swf file I loaded from code in the maintime in the parent swf.
There are 2 swf files. Main.swf and pConent.swf
1. Main.swf has code in the timeline of the first frame.
2. pConent.swf is loading a PACKAGE CLASS as file.
QUESTIONS
I am trying to call a function in it from its parent Main.swf. How do I do this?
Here is sections of the code from both. Thanks
Main.swf CODE /// is an AIR for Andrid swf
function LoadContent()
{
TheContent.load(new URLRequest( "pContent.swf"));
TheContent.contentLoaderInfo.addEventListener(Event.COMPLETE, LoadContentTWO);
function LoadContentTWO(e:Event)
{
Content = TheContent.content as MovieClip;
pContent = Content as Object;
addChild(TheContent);
var OSS:String = "device";
trace(pContent); //// comes out as: [object pContent]
pContent.GetOnlineStatus(OSS); ///// HOW DO I GET THIS TO CALL FUNCTION
}
}
A SECTION OF THE "CLASS" in pContent.swf I am trying to call
public function GetOnlineStatus(OS:String)
{
if(OS=="online")
trace("inside ONLINE" );
}
if(OS=="device")
{
trace("inside DEVICE" );
}
}
THE ERROR I AM GETTING
TypeError: Error #1006: GetOnlineStatus is not a function.
UPDATE: I decided to post the FULL PACKAGE ( my first) to see if I am doing it right.
package
{
import flash.display.MovieClip;
import fl.transitions.Tween;
import fl.transitions.easing.*;
import fl.transitions.TweenEvent;
import flash.display.*;
import flash.media.Sound;
import flash.system.*;
import flash.media.SoundChannel;
import flash.display.MovieClip;
import flash.events.MouseEvent;
public class pContent extends MovieClip
{
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
var ScreenY = flash.system.Capabilities.screenResolutionY;
var ScreenX = flash.system.Capabilities.screenResolutionX;
var swf:String;
var daSounds:String;
var images:String;
var videos:String;
var OnlineStatus:Boolean;
//++++++++++++++++++++++++
//++++++++++++++++++++++++
public function pContent()
{
BG.addEventListener(MouseEvent.CLICK, mouseHandlerdown);
}
//++++++++++++++++++++++++
//++++++++++++++++++++++++
//-------- * FUNCTIONS * --------
//-------------------------------
public function mouseHandlerdown(event:MouseEvent):void
{
alpha = .3; // testing
}
public function GetOnlineStatus(OS:String)
{
if(OS=="online")
{
OnlineStatus = true;
Security.allowDomain("*");
trace("inside THE PATH " + ThePath.text);
daSounds = "http://mycontactcorner.com/upload/files/";
swf = "http://mycontactcorner.com/upload/files/";
trace("inside THE DEVICE ONLINE" );
OnlineStatus = false;
swf = "";
daSounds = "content/sounds/";
//LoadMenu();
LoadStage();
LoadBeau();
}
if(OS=="device")
{
trace("inside THE DEVICE ONLINE" );
}
}
//------ * END FUNCTIONS * -----
//------------------------------
}// END FUNCTION pContent
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
}//// END PACKAGE
Don't be disappointed, but I won't have a "real" answer to your question, and I am really not going to work through all of your code to solve it, either. It is your own task to learn how to do this, and unless people here are very, very hungry for reputation, no one will do it for you - we will only help you to find the right way.
Your problem is not "packages and classes", so please do not give up on them. They will help you a great deal, once you've started to understand them. Your problem is, that you are not facing a single problem, but actually at least two (and quite substantial ones, I might add):
You need to go back to learn about the basics of object oriented programming in ActionScript. You won't have much luck getting answers to questions like this, otherwise. And believe me, I don't mean that in a patronizing way - it is simply a complicated matter, and it is hard to communicate complicated issues, both when you don't know the terms to express them, or when your counterpart doesn't understand them. Think of it like a high school math problem: You won't ever find a solution to your trigonometry question (or get a decent answer), unless you learn some basic algebra first.
You also have a problem related to loading, application domains, and the Flash Player security model - which are all far more complicated than what you should aim at when trying out OOP stuff. This can be a major obstacle, and unless you want to frustrate yourself, you should try to avoid it, until your program actually runs.
So this here is my advice: Always try to solve one problem at a time. Do not work yourself into such complex scenarios as the one you are in right now, but take step by step, until you've reached a level where you are confident with what you are doing.
Your first issue should be to understand what's going on with classes and objects. Everything else will come later. You should try to isolate your problem in the pContent.swf and get that to work first - or better yet, put everything you need for your program into a single file. Convert to using classes. Then, once you know how to work with those, start learning about more advanced OO, decoupling your code using interfaces, type casting and loading binaries at runtime.
//makes contact with classs but comes out as: [object pContent]
its because you said
pContent = Content as Object;
I am not sure why you are doing this extra step
Change it to this
Content = TheContent.content as MovieClip;
// pContent = Content as Object; //NO NEED OF THIS
addChild(Content); // just in case this gives error change it as addChild(Content as Object);
var OSS:String = "device";
trace(Content); //now see the difference
Content.GetOnlineStatus(OSS); // it calls now
Also, give the link where you posted that scary question :P if it has rest of the code
Sorry if this does not sound like an answer, but I'm going to write a couple of doubts that I have reading your code that can possibly lead to the solution:
Why are you casting it to MovieClip? If you cast it as MovieClip, the compiler it is going to tell you that the method "GetOnlineStatus" doesn't exist, because MovieClip class doesn't have it! I think you have to cast it as pContent
Why are you trying to casting TheContent.content? What is "content"? I had a look to your previous post and I cannot see anything called "content"?
If I ignore my second doubt (TheContent.content issue), I would change the code like this:
Content = TheContent.content as pContent; // your class it's called pContent
addChild(Content);
Content.GetOnlineStatus(OSS); // it calls now
Also, keep in mind that generally it's a good pratice to capitalize name of classes and not variables.
Let me know!
private function GetOnlineStatus
Try making this a public function instead. When it's private it can't be accessed outside the scope of the class that owns it.
I believe that in order to make this work, content property of the Loader. You have to create a reference to the loaded SWF as the class you are trying to call. This class has to be included in the main SWF's project. Then you can call the functions of that particular class in the child.
function LoadContent()
{
TheContent.load(new URLRequest( "pContent.swf"));
TheContent.contentLoaderInfo.addEventListener(Event.COMPLETE, LoadContentTWO);
}
function LoadContentTWO(e:Event)
{
var pContent:GetOnlineStatus = GetOnlineStatus(e.target.content);
addChild(e.target.content); //Assuming that "TheContent was
// declared as var TheContent:Loader , you'd be adding the loader to the stage when I think you actually wanted // to add the content.
var OSS:String = "device";
trace(pContent); //// comes out as: [object pContent]
pContent.GetOnlineStatus(OSS); ///// HOW DO I GET THIS TO CALL FUNCTION
// This should work now. If not, try to loading a function that is not the class' main function. Because I think you might get an "unable to call static function error". I'm a begginner too though, so sorry if I'm wrong. Example: pContent.GetOnlineStatusFunction(OSS);
}
This answer assumes that the pContent.swf contains a class file that looks like this:
package {
public class GetOnlineStatus {
public function GetOnlineStatus (OSS:String) {
//Do your GetOnlineStatus Logic. This is the main function.
}
/*public function GetOnlineStatusFunction (OSS:String) {
//Example non-main function
} */
}
}
Source: http://www.scottgmorgan.com/accessing-document-class-of-externally-loaded-swf-with-as3/