August 1, 2008 at 7:23 pm · 348 views · Filed under tutorial
Overview
Allowing users to use the keyboard as well as the mouse is a great way to incite interaction with your flash. This tutorial will show how to code it and what you can do with some keyboard events. This changed with actionscript 3, note this tutorial is AS3.
altKeY (Boolean) Indicates whether the Alt key is active (true) or inactive (false).
charCode (uint) Contains the character code value of the key pressed or released.
ctrlKey (Boolean) Indicates whether the Control key is active (true) or inactive (false).
keyCode (uint) The key code value of the key pressed or released. KeyboardEvent
keyLocation (uint) Indicates the location of the key on the keyboard. KeyboardEvent
shiftKey (Boolean) Indicates whether the Shift key modifier is active (true) or inactive (false).
Steps
import KeyboardEvent,
import flash.events.KeyboardEvent;
assign any keycodes
//keycodes
var left:uint = 37;
var up:uint = 38;
var right:uint = 39;
var down:uint = 40;
function keyDownListener(e:KeyboardEvent) {
trace(e.keyCode.toString());
}
or
function keyDownListener(e:KeyboardEvent) {
if (e.keyCode==left){
ship.x-=10;
ship.rotation = 90;
}
if (e.keyCode==up){
ship.y-=10;
ship.rotation = 180;
}
if (e.keyCode==right){
ship.x+=10;
ship.rotation = 270;
}
if (e.keyCode==down){
ship.y+=10;
ship.rotation = 0;
}
}
Example
Here we have a swf with the keyboard event listener on the stage, and feedback boxes to give us all we can know about the event. It will tell us about certain keys (alt, ctrl (cmd), and shift) with a Boolean, it will tell us the keyCode and the charCode. The keyCode is the number that is tied to the actual button pressed or key, and the charCode relates to the character represented by the button(s) pressed. So hitting ’s’ and then hitting ’shift + s’ will tell you different charCodes, ’s’ and ‘S’. but you’ll see that the s key has the same keyCode (you’ll also see the ’shift’ keyCode as well). If needed you can use the String.fromCharCode function to determine what the charCode for something is. The location on the keyboard is even reported, this helps distinguish between the left shift and the right shift and even the numbers across the qwerty and the numpad on the right of the screen.
July 14, 2008 at 8:02 pm · 531 views · Filed under tutorial
Overview:
Often I’ve had some dynamically created movieclip and then wanted to reference it in my code. This is hard to do if it is named dynamically as well, such as with an incrementing variable. If you use one (or more) variable to name an instance in runtime, you can’t always know what it will be called.
There are two ways (that I know of) to reference these clips, one is the array operator [] and the other is using the eval() function is as2 (but I’ve noticed that as3 has removed the eval function, so I’d recommend getting used to array notation).
Steps:
Create the object dynamically (or with a variable) (_root.myClip.duplicateMovieClip (”myClip”+i, i);)
Reference it with either array notation or with eval. (thisOne = _root["myClip"+i];) or (eval(”myClip” + i))
Example:
I create some movie clips dynamically using a for loop and name them all incrementally with a variable (myClip+i). But then i want to refer to some of them later, specifically. I don’t know what they are named though. They are all myClip1 myClip2 myClip3 and so on. I can use array notation to reference these (or eval). I’ve found it’s easiest to create a reference to the name once and then use it to refer to the clip I want. I imagined a scenario that when you click a mc you would want a different one to be moved. So clicking myClip3 moves myClip4 and so on. I’ve made it wrap so that 5 moves 1… They change the _y property of the next to match the one that’s clicked. Clicking the refresh button will loop through all the clips and (this time using eval) randomize the y coordinate.
this.createEmptyMovieClip("outer_mc", 1); // create a mc called outer_mc
outer_mc.createEmptyMovieClip("inner_mc", 1); // create a mc called inner_mc inside outer_mc
// 3 different ways of targeting inner_mc
trace(outer_mc.inner_mc);
trace(outer_mc["inner_mc"]);
trace(this["outer_mc"]["inner_mc"]);
// all output _level0.outer_mc.inner_mc
TheCanadian@Kirupa states it nicely: The Problem
How can I reference objects using a variable? This is commonly a problem with dynamically created buttons:
The Answer
This is probably the question that gets asked the most. Referencing an object with a variable is done using something called associative array referencing or array notation. The fundamental concept behind this is that:
Are the same thing. Associative array referencing follows the pattern of scope["prop"] where scope is the object which contains the property and prop is the name of the property you wish to reference. Save appearance, array notation works in exactly the same way as dot notation.
Going back to the original, problematic, example, the correct code would look like this:
The button string is concatenated (joined) with the i variable, forming a new reference with each iteration of the loop. First button0, then button1, et cetera.
That’s the quick, but some of you may think that that’s the same notation that is used with instances of the Array class. While that is true, the converse is actually more correct: Array instances use that notation.
Arrays are exactly the same as generic Objects, the only difference is that they have a collection of methods to deal with their properties. And because they require a need for organization, they typically only use numerical properties. Given the array myArray = ["a", "b", "c"], you could theoretically reference the indices using myArray.0, myArray.1 and myArray.2. The reason that we must use array notation is because the compiler doesn’t allow the reference of numerical properties with dot notation.
June 24, 2008 at 10:34 pm · 843 views · Filed under tutorial
Overview
Having things drift around or move randomly has always interested me. Having an animation that is never going to be the exact same thing is very exciting. The focus turns from key-ing exact animations to programming a feel and letting the animations take car of themselves! One type of seemingly random motion is Brownian motion. This gives the movement a random walk wandering look, it will just drift around with no real direction.
Steps
Step by step this process is very simple. In every random motion you create the random number, and apply it to the property. If you want constant random action (motion) rather than just random placement, you repeat that over and over.
Make a random number (random velocity)
Apply the random number (apply velocity to property)
Repeat (if needed)
To create a random number in actionscript, use Math.random(), which creates a random number between 0 and 1. Usually you’ll want to scale it to a range you want to use. If you want a number between 50 and 100, you’d do Math.random() * 50 + 50. *50 to scale it to 0-50, and + 50 to bring it up to 50 - 100. Also if we want to get a 100 range around 0 (-50 - 50) we would do Math.random() * 100 - 50. In the code below I’ve abstracted this to Math.random() * this.randomRange - this.randomRange/2.
Example
Here I’ve got dots created and placed randomly, with randomly set scale and alpha. On every frame each dot has a random velocity applied to it’s x and y coordinates.
The yellow dot is the simple example (code below) and the rest are included in the complex example below.
Actionscript
Simple Example:
dotOne.onEnterFrame = function(){
//create a random velocity for x and y direction
vx = Math.random() * 4 - 2;
vy = Math.random() * 4 - 2;
//apply velocity to coordinates
this._x += vx;
this._y += vy;
}
Complex example:
var numDots = 25;
var randomRange = 1;
for(var i=1; i<=numDots; i++){
//create a new dot
duplicateMovieClip(_root.dot, "dot"+i, i);
//save it's ref path for use
theDot = _root["dot"+i];
//give it random coordinates
theDot._y = Math.random() * Stage.height;
theDot._x = Math.random() * Stage.width;
//give each dot a distinct random range
theDot.randomRange = i/numDots;
//give each dot a random size and transparency
theDot._xscale =
theDot._yscale =
theDot._alpha = i*4;
//apply this code on the dot every frame
theDot.onEnterFrame = function(){
//create a random velocity for x and y direction within the specifically created random range for each dot
June 5, 2008 at 8:03 pm · 2,120 views · Filed under tutorial
Overview
In flash you can have text areas that are rendered as html. You can also apply formatting styles to this html. This will show a simple example on how to apply css to html text in flash. I’ll do a simple anchor tag style to show you the ropes. We’ll style a link to be underlined and then when you hover or mouse over it, we’ll change the color. It’s a design style that is widely used online in html, but flash doesn’t natively do it. As a matter of fact, flash doesn’t even natively underline links.
Steps
Import TextField.StyleSheet
create a style sheet object: var myCSS:StyleSheet = new StyleSheet();
Specify your styles: myCSS.setStyle(”a:link”, {color:’#0000CC’,textDecoration:’underline’});
Ensure that the text box is html enabled: myHTML.htmlText = myHTMLText;
Apply the style sheet object to your html text box: myHTML.styleSheet = myCSS;
Example
Actionscript
importTextField.StyleSheet;
myHTMLText = "
<h1>HTML Text (sample header)</h1>
Here is some <em>sample</em> <strong>html text</strong> "+
"filling a text box <a href="http://blog.circlecube.com">this link to circlecube</a> and example headers"+
May 30, 2008 at 7:56 pm · 1,924 views · Filed under tutorial
Add this to the list of things I should have already known!
Story
I’ve got an html enabled text box and was trying to devise a way that I could have a hyperlink anchor tag not link to a webpage but actually do something flash. It didn’t seem possible, and I looked through all the different html css combinations I could think of. I finally resorted to trying to use some component like Deng or FlashML. FlashML had a smaller footprint and seemed to do more what I wanted, so I started investigating it. To my dismay, the support for it was few and far between. I found an older version that came with an example file and then a newer one with some documentation but no example and I found no examples any where else. So Lee, if you ever read this, some new examples could be nice. In the documentation I was reading about a functino called AddASFunction and the example html line was very interesting:
I started looking through the rest of the documentation to find this asfunction use. But all it had was:
The href attribute can include the asfunction string which allows the link provided by the anchor to call a function in Flash. More of this can be found within the addASFunction definition in this help document.
I knew I was on to something, asfunction. So a quick google search and I found the official doc! I was shocked that I had the tool to do this the whole time! Well, shocked and feeling like an idiot for never having heard of it before. I knew it could be done somehow, but had no idea that it was already a feature of htmlText in flash! So now that you know my embarrassing story, I’ll let you in on the secret.
Overview
In flash, you can allow html text within a text area. You either set the text html property as true with actionscript (my_txt.html = true;) or click the ‘Render text as HTML’ button in the properties window of the text area. You cannot enable html text on static text areas however. You can have links and various html elements (but not full html). Usually links have a url in the href attribut of the anchor tag, but flash will read a special value of ‘asfunction’ which specifies that an actionscript function is to be called rather than a url. The correct syntax is asfunction followed by a colon and then the name of the actionscript function to be called, optionally followed by a comma and a possible single argument to be passed to the specified function (href=”asfunction:functionName,argument”).
Steps
Enable html in the text box.
Have your function (ex: functionName) ready to be called from the html link.
Give the href attribute of the anchor tag a property “asfunction:functionName,argument” Notice that the official documentation calls for spaces after punctuation, but any space you put after the colon (:) or comma (,) will be sent to the function in the argument, or will expect a space in the function name and give you a headache.
Example
In this example I’ve got an html enabled text box with 4 links. The first is a standard link (I hope you know what that does). The next link calls an actionscript function with asfunction. The third link sends a single argument to another function. And the last link sends multiple arguments to yet another function. Wait! Multiple arguments? I thought I said only one was supported, well this example shows how to send multiple arguments disguised as a single param and parse them. It’s pretty simple actually.
Actionscript
importTextField.StyleSheet;
myHTMLText = "Sample text in an html enabled text box. "+
"Here's a normal link to <a href='http://blog.circlecube.com' target='_blank'>circlecube</a>! "+
"And some more links that don't go anywhere, they call functions in actionscript. "+
"<a href='asfunction:clickLink'>Click this one</a>, "+
"to see the actionscript function called from the html text box. "+
"<a href='asfunction:clickWithArg,Click this too'>Click this too</a>, "+
"and see that the actionscript function you're calling can have an argument passed to it. And "+
"<a href='asfunction:clickWithMultipleArgs, one,two,three args'>click me three and four</a> "+
"to see a way to send multiple arguments from your htmlText. "+
"Also, one last example of what not to do "+
"<a href='asfunction: clickWithArg, arg with preceding space'>Click for nothing</a>";
May 22, 2008 at 9:36 pm · 2,550 views · Filed under tutorial
I’ve had a couple special requests to explain flashvars and how to use it and show it in action.
Overview
The property “FlashVars” can be used to import root level variables to the flash movie or swf. The flashvars propery is used in codes for embedding flash in the html page. The string of variables passed in as flashvars, will be imported into the top level of the movie when it is first instantiated. Variables are created before the first frame of the SWF is played. The format of the string is a set of name=value combinations separated by ampersand (&) symbols.
Steps
Include the flashvars property in your embed codes and voila! You have these variables to use in your swf.
That’s the one step
Code
HTML Embed Codes
Here's some sample embed codes, including object and embed tags:
May 21, 2008 at 8:45 pm · 576 views · Filed under tutorial
Intro to CSS
We use css to apply styles to certain elements on the page, we can target any div like this:
HTML
<div>Text</div>
CSS
div {
css-property: value;
}
Any class selector <div class=”divClass”> like this:
HTML
<divclass="divClass">Text</div>
with this:
CSS
div.divClass{
css-property: value;
}
<!-- or simply -->
.divClass{
css-property: value;
}
or any id selector, <div id=”divID”> like this:
HTML
<divid="divID">Text</div>
with this:
CSS
div#divID{
css-property: value;
}
<!-- or simply -->
#divID{
css-property: value;
}
These are the basics of css. Use an element tag name to target it, use a dot to access class names and a hash (#) to represent id names. A lot can be done with just that, but sometimes you may want to access something differently, an option is to use attribute selection.
Overview
More advanced we can apply styles to elements based on their attributes. Attribute selectors use the attributes of the tag.
We can use attribute selection to specify certain elements to stylize. For example if we have a page with many images but only certain ones have title attributes, which we want to stand out more, this css rule would do the trick:
CSS
img [title]{
border: 2pxsolid#000000;
}
It would cause any image with a title tag (no matter what the value of the title tag is) to have a 2px wide solid black border, such as <img title=”MyImage” src=”/images/sample.jpg” /> or <img title=”" src=”/images/sample.jpg” /> but not <img src=”/images/sample.jpg” /> because it has no title attribute.
Further we can specify which values of the title attribute we want to target. If we want to stylizee links to a certain site we can do this: a[href="http://blog.circlecube.com"] { }
CSS
a[href="http://blog.circlecube.com"]{
background-color: #EBEBEB;
}
it would style <a href=”http://blog.circlecube.com”>This link</a> but not <a href=”http://blog.circlecube.com/2008/05/21/”>this one</a> because it is not an exact match, nor <a href=”http://www.google.com”>this one</a> because it isn’t a match either, or at all.
For another example, if we want to stylize local links differently than absolute links, we’d want to look at the beginning of the attribute’s value only so we’d use ‘^=’. We could have something like this:
a[href^="http://"], a[href^="https://"] {
background: url(/images/external.gif) no-repeat right center;
padding-right:20px;
}
it would style <a href=”http://www.google.com”>This link</a> because it begins with ‘http://’ but not <a href=”/2008/05/21/”>this one</a> because it is does not begin with ‘http://’. But it would also style <a href=”https://paypal.com”>this</a> because it matches the selector after the comma ‘https://’, and even <a href=”http://blog.circlecube.com/2008/05/21/”>this</a> will be styled, because the link is absolute (even though it is local) so be careful with how you use it.
April 24, 2008 at 8:07 pm · 1,477 views · Filed under tutorial
Overview
The Shared Object is like a cookie for flash. It lets flash store some data on the local machine, so between sessions it can remember things. Learn more from wikipedia.
Shared Objects are used to store data on the client machine in much the same way that data is stored in a cookie created through a web browser. The data can only be read by movies originating from the same domain that created the Shared Object. This is the only way Macromedia Flash Player can write data to a user’s machine. Shared Objects can not remember a user’s e-mail address or other personal information unless they willingly provide such information.
I’ve seen many Local Shared Object tutorials and examples, which have users input their name and/or hometown and other filler data. But I wanted to show how to creatively incorporate shared objects into interactions. So I’ve thrown in many simultaneous examples including the uber-simple ‘input your name and I’ll remember it’ approach. I hope I didn’t throw in so much that it got confusing… just let me know if you have any questions or anything is unclear. Keeping it simply and broad there’s only a few things to know about Shared Objects.
Steps
Simply put there are only a couple things to worry about with Local Shared Objects
Create them.
As in create the shared object
Write them.
As is write to the shared object
Set them.
As in setting variables in the shared object
Get them.
As in getting variables back out of the shared object
Clear them.
As in clearing the shared objec
Actionscript
here’s samples on how to do each of those
/* Create them. */
//make Local Shared Object named myLocalSO(in as) called "myflashcookie" on disk
var myLocalSO:SharedObject = SharedObject.getLocal("myflashcookie");
/* Write them. */
//flush the SO, write the SO to disk
myLocalSO.flush();
/* Set them. */
//set key's value to specified value in SO
//key is the name of the data
//val is key's value
function setVal(key, val){
myLocalSO.data[key] = val;
trace(key +" set to "+val);
/* including writing to Shared Object in the setter function */
//flush the SO, write the SO to disk
myLocalSO.flush();
}
/* Get them. */
//get key's value from SO
function getVal(key){
return myLocalSO.data[key];
trace(myLocalSO.data[key] +" received from "+key);
}
/* Clear them. */
myLocalSO.clear();
Example
here’s my colorful example.
The purple/yellow circle is draggable, so place it where you want it. Enter your name and age in the input boxes. Press the center red ‘Set cookie’ button to copy those values to the shared object that is on your computer now. The red transparent circle represents the cookie positions. You can position the purple/yellow circle from the cookie contents with the dark green ‘Position from cookie’ button, or position it randomly with the blue ‘Position randomly’ button. Erase the cookie with the orange ‘Erase cookie’ button. Toggle easing (animation) with the Bright green button (which changes to dark red when off), it tells the current mode of ease. I have the cookie coordinates displayed and the current coordinates of the purple/yellow circle also displayed.
The cookie includes a date object, which is used to calculate the age of the cookie (watch it reset when you erase the cookie (orange button)).
The ‘All Time Visit’ stat is the only thing that does not get reset when you erase the cookie,
