Flash components overview

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Overview

Flash CS3 component library

Components are prebuilt interface elements (widgets) that will speed up programming of interactive Flash pages. This is part of Flash CS3 tutorials.

Learning goals
Learn how to create and use some Flash 9 (CS3) components
Learn a little bit of Action Script 3.0 to run something with a button.
Prerequisites
Flash CS3 desktop tutorial
Flash drawing tutorial
Moving on
The Flash article has a list of other tutorials.
Flash Video component tutorial
Quality
This text should technical people get going and may not be good enough for self-learning beginners. It can be used as handout in a "hands-on" class. That is what Daniel K. Schneider made it for...
Level
It aims at beginners. More advanced features and tricks are not explained here.
The execturive summary

Flash has a few built-in components (called widgets or gadgets in other contexts) and the will allow to you to build an interactive environment more quickly than by coding all by yourself.

However, using these components still requires basic knowledge of ActionScript. In this article we will try to show a few design patterns that you can copy and adapt.

The executive summary - buttons
  • Open the component library (Window->Components or CTRL-F7)
  • Drag a component to the stage
  • Fill in some Parameters
  • Add some action script


Introduction

ActionScript (AS2) and ActionScript (AS3)
  • In CS3, a component library is available for both versions
  • The AS3 one is smaller as you could see in the screenshot above

In this article we going to look at User Interface components

To open the component library
  • Window->Components or CTRL-F7
  • I suggest to dock it against your library.

A menu-based slideshow with the AS 3 button component

Goal

The goal is to make a sort of simple Flash Webpage. The user at all times will have a menu to the left that will allow him to navigate to different contents.

We will build several versions of this. Have a look at the "standard" AS 3 menu-based slide show

Step 1- Planning the layers

In this example we will work with five layers:

  • Actions: will include a little Action Script code
  • Buttons: will include the buttons (displayed on all "pages")
  • Pictures: Contents we want to display
  • Credits: A special page for the "who's done it" (we also could have used the pictures layer for this).
  • Background: A simple background that will remain stable.

So the timeline roughly will look like this:

Timeline of the menu-based slideshow

Create these layers now

Step 2 - Add pictures
Step 3 - Get buttons from the library
  • Select the buttons layer
  • Open the component library, select "User Interface" and drag as many buttons to the stage as you have pictures. Add an extra one for the credits page.
Button of the Flash CS3/ActionScript3 component library
Step 4 - ActionScript 3 principles

ActionScript 3 does not allow to attach scripts to buttons. One can only script frames in the timeline. In order to script a component we bascially have to do three things.

  1. Give name to the component (i.e. the movie instance)
  2. Fill in some parameters, e.g. add a label for the button
  3. Add some actionscript to the timeline that will:
    • Associate a user interaction event (e.g. user clicks) to some action function
    • Program the action function
Step 5 - DoIt for each button
  • Click on a button (make sure to lock other layers)
  • Select the Parameters panel (menu Window->Properties->Parameters)
  • Give the button instance a unique name without whitespaces: e.g. btn_rainbow (since this button will lead to a rainbow picture).
  • Then change the label parameter of the button. This is what the user will see. Type anything there, but don't make it too long (it's a button after all). If your text is bigger than the label, change it's width in the same panel, i.e. modify the W: field.

Notice how different it is to work with a component vs. using buttons as explained in the Flash button tutorial]]

Parameters of the ActionScript3 butoon

Make sure you did this to all buttons.

Step 6 - Open the ActionScript panel
  • Open the Action Layer, Click in Frame 1
  • Hit F9 to open the "Actions-Frame" panel. In case it is docked with the parameters, you may undock it to have some more space.
  • Then paste all the code below.
Step 7 - Stop the animation from playing in frame one

This will stop Flash from playing all the frames 

  User must stay in Frame 1 */

stop();
Step 8 - Associate buttons with handler functions

Associate a handler function for each button instance:

Syntax: button_name.addEventListener(Event.type, function_name

Lines below mean:

  • If the user clicks on the btn_rainbow with the mouse, then the function clickHandler defined below will execute.
btn_rainbow.addEventListener(MouseEvent.CLICK, clickHandler);
btn_tecfa.addEventListener(MouseEvent.CLICK, clickHandler);
btn_bosses.addEventListener(MouseEvent.CLICK, clickHandler);
btn_my_computers.addEventListener(MouseEvent.CLICK, clickHandler);
btn_credits.addEventListener(MouseEvent.CLICK, clickHandler);
Step 9 - Write a clickHandler function

Note: you could have chosen an other name, but as rule function names should be sort of meaningful to you and people who read your program

Instead of writing a function for each button, we just created a single one. In order to understand which button was clicked, we ask from the event the label of the button(event.currentTarget.label). Then we gotoAndStop(x) animation at frame x 

function clickHandler(event:MouseEvent):void {
	switch (event.currentTarget.label)
	{
		case "Rainbow" :
			gotoAndStop(2);
			break;
		case "TECFA" :
			gotoAndStop(3);
			break;
		case "Bosses" :
			gotoAndStop(4);
			break;
		case "My computers" :
			gotoAndStop(5);
			break;
		case "Credits" :
			gotoAndStop(6);
			break;
	}
}
Extra Step 1

This shows how to open an URL in a WebBrowser 

btn_edutech_wiki.addEventListener(MouseEvent.CLICK, GoToUrl);

function GoToUrl(event:MouseEvent):void {
	var url:String =  "http://edutechwiki.unige.ch/en/Flash_components_tutorial";
	var request:URLRequest = new URLRequest(url);
	try
	{
		navigateToURL(request, '_blank');
	}
	catch (e:Error)
	{
		trace("Error occurred!");
	}
}
Results

Grab the flash-cs3-flash-cs3-simple-slide-show-menu.* files from

http://tecfa.unige.ch/guides/flash/ex/components-intro/

Too complicated ?

You may write this code in a slightly simpler but less elegant way: If you have no programming knowledge, rather work from this code below: 

/* This will stop Flash from playing all the frames
   User must stay in Frame 1 */
stop();

/* Associate a different handler function for each button instance:
   Syntax: button_name.addEventListener(Event.type, function_name
   Lines below mean:
   * If the user clicks on the btn_rainbow with the mouse,
     then the function clickHandler defined below will execute
*/
btn_rainbow.addEventListener(MouseEvent.CLICK, clickHandler1);
btn_tecfa.addEventListener(MouseEvent.CLICK, clickHandler2);
btn_bosses.addEventListener(MouseEvent.CLICK, clickHandler3);
btn_my_computers.addEventListener(MouseEvent.CLICK, clickHandler4);
btn_credits.addEventListener(MouseEvent.CLICK, clickHandler5);

/* Each function defines where to move the playhead in the animation.
   E.g. clickHandler2 will go to frame 3 and then stop
   */

function clickHandler1(event:MouseEvent):void {
	gotoAndStop(2);
}
function clickHandler2(event:MouseEvent):void {
	gotoAndStop(3);
}
function clickHandler3(event:MouseEvent):void {
	gotoAndStop(4);
}
function clickHandler4(event:MouseEvent):void {
	gotoAndStop(5);
}
function clickHandler5(event:MouseEvent):void {
	gotoAndStop(6);
}

/* This shows how to open an URL in a WebBrowser */

btn_edutech_wiki.addEventListener(MouseEvent.CLICK, GoToUrl);

function GoToUrl(event:MouseEvent):void {
	var request:URLRequest = new  URLRequest("http://edutechwiki.unige.ch/en/Flash_components_tutorial");
	navigateToURL(request, '_blank');
}
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