The Flash Connection Make mine Actionscript 3.0!

I'm really loving the technique! Thanks so much. 

I've run into a situation that I don't understand. I want to have a navbar on stage at all times, and then by clicking on a button in that navbar, cause another screen to load. How do I call a handler in my Main object (that adds and removes children) from my navbar object? I have tried just calling my gotoHome() function in the Main script from the NavBar script, but I get errors.

JLM,

Thank you for your comment. Here is my humble take:

PopUpManager was part of the V2 component set. It allowed you to (fairly) easily create and pop up an instance of one of the other component classes. The component set in Flash never went over very big, however, as far as I know and from what I've read and heard. The intention was to make a set of components so that the average person, programmer or not, might be able to just jump in and start making applications with them. It didn't quite work out that way. And if you did get the hang of the components, you still wound up with applications that looked like somebody used components, as they were notoriously almost impossible to skin.

I don't want to pretend to know components inside out, because I don't. Nor do I know their full history. But Flash still comes with components, and they apparently kept the most popular ones, and weeded out the not-so-popular. And they brought back the UIScrollbar because of popular demand. And they made them all a lot easier to skin.

I have mostly for the most part shied away from components, except I experiment with them sometimes. My advice, though, is that you should write your own popup window class, that extends Sprite. You will be able to customize it a lot better, and get the look you want right off the bat. Just ask yourself what would be the parts of it? A background, a dynamic textbox for content text, a dynamic textbox for the title bar, a "close" button, etc.... Those would be its properties. What would be its methods? In other words, what should you be able to tell it to do from the outside? Well, you should be able to set its title and text, you should be able to make it open and close, and you should be able to size and position it. Also you might make it autosize itself depending on the size of the content textbox. One tricky aspect is going to be how to make it "modal." A modal window won't let you interact with the rest of the application until you dismiss it.

Designing classes is fun, when you start getting the hang of it. I am still intermediate myself, but I'm coming along okay. I think (hope!) that's the appeal of my tutorials, I am one of you, your fellow traveller.

Jody

eheidner (and lucky),

You can have your buttons on the main timeline, then just program those stage instances in your document class. Then all your screen switching is done from the main class, and maybe that is neater. But if you have screens that are the same size as the stage, when you use addChild() to display them, they will go on top of the display list and cover up your navigation buttons. To get around this, you might use addChildAt(screenName, 0) so that you always add a screen to the display at the lowest depth, then it will tuck neatly behind your buttons. Of course, in this case, you will have to design your screens to allow for the fact that the buttons will now be covering up a portion of your screen.

I have put together a wham-bam simple example of what I am talking about, complete with button disabling and all that. structure_tutorial_buttons_in_main.zip. Don't expect any great designing in this one, it's just to demonstrate the stucture. The Main.as document class is commented as to what's going on.

You'll notice I just used separate buttons, but if you wanted to make those buttons part of a container navigation bar, you could do that too. Just nest them inside a container movie clip, and use dot syntax to program the nested buttons.

Another idea might be to have a "fly out" menu that doesn't cover up much of the stage until you mouse over it. I guess any number of variations are possible.

Hope that helps!

I'm following your tutorials and very eager to learn tricks and tips post by you. Really Thanks a lot. And I need Alert component in AS3.0 best reference site can any body helping me in welcome!.. Thanks and regards, Logeshkumar P.

Hello -

Thanks for this tutorial. I am using it on an actual project and am hopeful it will make it efficient and will improve my OO skills in the process. I came up with an idea that could be a slight improvement and am interested in hearing what you think of it. I thought I'd try consolidating all the goto functions into one like this:

public function gotoScreen(screen):void {
 removeChild(currentScreen);
 addChild(screen); currentScreen = screen;
}

That would cause you to change the class code to be (for example):

MovieClip(parent).gotoScreen(MovieClip(parent).learn);

Do you think there are any possible issues that could come up as a result of doing it this way? 

Cool tutorial.

on the last page of the tutorial, when you explaind about "reset" the drag page by instanciating a new Drag object.

I wonder, what happens to the "old" Drag object? Does he still holds its value, or is it become ready for garbage?

Tzachi

 I'm trying to follow the idea with a little different method:

Instead of linking a library symbol "Intro" to a class named "Intro", I'm trying to link a swf named "Intro.swf" to a class "Intro".

The idea is to load from the main movie a swf called Intro.swf that all its code is written in a linked class (Intro.as ?)

But it doesn't work.

Any help?

Yes, the Intro.as file would have to be the document class of the Intro.fla file. You will also have to use a loader object to load the external swf.

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Hello Jody,

Your article has really been an eye-opener to say the least! More like a revelation better describes it! I am fairly new to Flash and writing Actionscript so having some of the basics has helped me get a handle on the concepts/code in your tutorial! But this approach to organising a Flash project makes so much sense! And as you have so wonderfully illustrated how it works. And as you say it’s not too difficult to conceive and do. I haven't come across anything else (Flash tutorials) that incorporates the use of Classes to navigate through "screens" offering a better alternative to timeline navigation. In a way, it has pointed out to me how my project could be improved because I was experiencing all the same problems you mentioned at the beginning of your article. Also I wanted to praise you for was how well you are able to explain some of the more complex concepts, very logically and clearly, not losing a newbie like myself.

You have made me rethink how I have been developing my first Flash project so that I am now going to rework it following your method. Here's a link to a demo of what I've done so far. www.eddiesoft.id.au/Ben/WaterWise.html

My one uses the timeline with frame labels for navigation but it shouldn't be too difficult to change using your method. Thanks again for this fantastic tutorial! I have also just finished reading your tutorial on AS3 Dropdown Menu with Reusable Classes and will try to incorporate that too.

I was thinking about how I could incorporate some other custom graphics or objects in the Dropdown Menu instead drawing the shapes as you have shown in that tutorial?  

Regards, Ben.

Like the others before me I want to say "great job" on this tutorial. And thank you for the time you take to explain what the code is doing in depth in-stead of skimming over the information. I look forward to working through some of your others.

I have one question... in the text you state "Classes are all nice and encapsulated that way. By default, they don't share information with each other, and later I will show you how to make them share with each other just the information you want." I may have missed how you share information between classes. What I am looking for is if I create a variable in a class and need to access that information in another class how does that happen?

Jody this is a really great tutorial! As a Flash Educator it helps a lot to teach this approach. I also implemented something like your approach in my application Simple Class Generator for AS3.

sewingbuttons,

Thanks for your comments. I think those are probably the nicest compliments I've ever received, and they certainly made my day when I first read them! I took a Java class at a local community college a long time ago, but at the time I just didn't get the whole object-oriented thing, and I didn't really become proficient in Java, even though I got an A in the class (and my final project was kind of cool, but I remember the way I did it was mostly by brute force programming!). Later I also took a class on Visual Basic, and I got a better idea of OOP through that. But mostly the OOP stuff didn't start clicking in my mind until later when I was learning Flash, but the earlier Java training (and VB) was not a complete loss, because now I can see what they were talking about.

BTW, I just finished a new tutorial that might be right up your alley: Flash - The Big Picture. It deals with classes, packages, the classpath, and how they all relate to Flash.

--Jody Hall

Ynot sailing,

Anyone will struggle with anything the first time(s) they try it. And the person who's been doing it for ten years (or more) will make it look easy. If I tried sailing I would be lost and probably not make it back to the shore.

But if a person decides they like something well enough to want to get good at it, and they persist, they will succeed at whatever it is. You just have to decide (or discover) that you really, really like it. Our trouble is (and I am guilty of this too!) that we always want to master something practically overnight! I'm waxing philosophical here, but I think it's true.

As for your code you are having trouble with, you will overcome by really studying the lines of code and what they do. The fact that they are in a class or on the timeline or whatever isn't so important, what matters is what the line of code is telling the computer to do. So the code that I put into a class will still work in other contexts.

There are lines of code that tell the object being dropped to go back to where it started. Take those lines out. There are lines of code that disable the object from being picked up and dragged again. Leave those lines in. Result: the object will stay wherever you drag it to, and you won't have the opportunity to drag it again.

Anyway, if you are still really stuck, write to me using the contact form on this website. I'll write you back and then you can send me your files, and I will help you.

Jody

Hi Jody

I've hit a road block and would like some help please. I've been struggling with this for the last couple of days without success. Like Edison I found lots of ways that do not work :-)

I've modified the dropMe function to add a score counter for each correct hit and an if statement to display the score in a dynamic text field when all the objects have been placed.

All works well as long as I have the dynamic text field on frame 1 of the dragMe movieClip.

I tried to put it on another  keyframe on the dragMe MC and added a gotoAndPlay statement using a frame label.

I get a "TypeError: Error #1009: Cannot access a property or method of a null object reference.     at TestEnglish/dropMe()" message.

If I comment out score_txt.text = "Scored " + scoreCounter + "/26"; the gotoAndPlay works fine.

As stated earlier if I have the dynamic text field score_txt on frame one of dragMe movieClip it correctly displays the score.

Ultimately I want to be able to display different info depending on the score achieved.

For example if the client does not score 100% they will be given guidance on what they did not place correctly. (I'm in the process of learning how to do this part but cannot progress until this current problem is fixed). When the score 100% they will go to a congrats page (fireworks; I'm looking forward to playing with particles but need to be able to walk before I start running :-)).

So here's my questions.

1. What do I have to do to get the If statement to either take me to another frame on the dragMe MC timeline and address the dynamic text field

OR

2. Take me to a completely new movieClip.

OR

3. Is there another way to achieve what I am trying to do.

Thanks in anticipation

Tony

Karl,

The purpose of the article was to point out the problems with timeline navigation systems, and to present a much better alternative with MovieClips as "screens." The Intro, Learn, and Drag screens made good examples, and I probably strayed from the main subject matter myself in describing them in detail. They could have been just blank screens, and I could have still made my point, but I also went into things like tooltips, drag and drop, etc. I just wanted to show how all this code was encapsulated into each screen's class and was independent of everything else. Again, as opposed to the timeline alternative. In comparison, the "MovieClip as screen" approach seems light years ahead to me.

Beyond that, I'm not opposed to anyone coming up with any kind of architecture they want, or even discarding this one if they find something better. I'm always exploring other ideas myself, usually with the thought of making things easier or simpler, if at all possible.

The reason I don't make each object responsible for its own events like you suggest (and I have tried it) is because it tends to require each object to also know about all the other objects. If I am making a drag and drop matching game, for example, and the events are inside the object, how will I evaluate whether it hit its intended target when it drops? I would have to make the class somehow aware of all the other objects (or at least the one it's intended to match) in order to do my evaluation right there in the class. This means that every object that's going to be dragged will need a reference to all the other objects as well. OR I could dispatch an event letting my outside code know that the object has dropped. But in that case, I'm doing the evaluation from outside the class anyway, so (in my thinking anyway) the whole thing might as well be programmed from the outside, because the parent object has all these references that are needed.

So that doesn't sound easier or more flexible to me, it sounds like a lot more hassle than just programming it from outside the class. Once again, though, I am not opposed to someone taking off with this and trying it. If you'd like to do that, I'd be glad to see it, and maybe I will learn something new too, which is always good!

Jody

Thank you for the article, learned a lot. He was learning to program in C + + and I dropped by the flash was a great choice was very easy to learn about classes, now do not want to stop programming in flash.

Chi,

I often say that someone's comment made my day (and I always mean it). This one was like that--only times ten. Anyway, it's always good to know someone appreciated and got a definite, measurable benefit from an article of mine. It lets me know I struck a chord with someone, and I really appreciate the feedback.

I was not familiar with the Katherine Ulrich book (just now looked it up on Amazon), but there is another QuickStart guide by Russell Chun that I often recommend as a good introduction to Flash and AS3. Everyone else always recommends "Essential Actionscript 3.0" by Colin Moock, which is a fantastic book, but in my humble opinion, too deep for beginners and not centered enough on Flash.

I have seen quite a few massive timeline navigational nightmares that people have created. And yet, sometimes when I suggest they adopt the "MovieClips as screens (w/classes)" thing, they somehow think it's going to be too hard to learn how to do it. I don't really have the time to show them, at least not one person at a time, so that's why I wrote the article.

I am glad that you intend to keep reading. Click the "All tutorials" link at the top of the page. "Streamlining your AS3 code" is a good, simple article to start with, as it spells out several techniques I have found myself using over and over in my own projects. "Flash: The Big picture" will give you a much better idea of how Flash works with classes, packages and the classpath, and how you might structure your folders for your projects. Presently I am considering writing a tutorial on using the PureMVC framework, because very little of what's out there is centered on Flash as opposed to Flex.

Stay tuned, and thanks again! You've encouraged me more than you know.

Hi Jody,

I do most of my coding on the weekend, hence my saturday questions. I am getting close to having my app complete, but have a couple nagging questions that I can't quite figure out.

1) Passing a variable between objects. Lets pretend in your example above you have a String type variable in the Learn object.

var example:String = "test";

Now lets say you want to use that variable in the drag.as object.

trace(example);

Of course as written, we will get the error message of "1120: Access of undefined property example", since their is no variable named "example" in drag.as.
My understanding is the I need to dispatch an event to pass the variable, but i m struggling with the syntax. Any help is appreciated.

2) this is a followup to a prior question you helped me with. I needed to activate keyboard buttons for an object, and I did that by including the keyboard event listener in the function associated with for ADDED_TO_STAGE event. It is mostly working, but when first enter the object. requires one mouseclick first, then it works fine from then on. let me know if you have any thoughts. i will also go reread you advice last time.

Thanks much,
Chi
-

Jody,

Fantastic information. You definately could make this a tutuorial entitled "Passing variables between classes". I had no idea the variety that existed. Number 2 was the easiest for me to get my hands around and since I just need to pass 1 or 2 items, it was very straightforward and did the job.

Thanks a million!
Chi