2533CIT: Multimedia IIB

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2533CIT Multimedia IIB

• Week 1 Introduction to Flash, Actionscript and
  Supporting Tools

Coridyn Fitzgerald-Hood
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Finding your feet
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Introduction to Flash

• Flash
• Vector-based multimedia authoring tool,
• Utilises a Timeline metaphor,
• Programming/scripting interface similar to
  Director.

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Supporting Tools

• Editors
• Sepy Actionscript Editor
• www.sepy.it
• FlashDevelop
• http//osflash.org/flashdevelop

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• Why use an external editor?

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• For the same reason you dont use Notepad
• (I hope)

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Features!

• Code hints,
• Better project support,
• Improved file management searching, search in
  files,
• Refactoring it programs for you,
• A decent text editor.

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Flash Basics

• Timeline

Current playhead position
Keyframe with script
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Symbols

• Symbols are the building blocks of Flash movies.
• Symbols can be either
• Movieclip
• Button
• Graphic

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MovieClip

• Has an independent timeline.

Current editing level
Movieclip frames
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MovieClip

• Can be instantiated (added/created) at runtime,
  using Actionscript
• Can be assigned an Actionscript class and run
  custom code.

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• Can hold nested objects (Buttons, Graphics, Other
  MovieClips),
• Allows you to organise your graphics and
  interaction.
• Can listen/respond to user generated events
• Key presses,
• Mouse moves,
• Mouse clicks (press and release).

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Button

• Has a timeline (of sorts).

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Button

• Cannot be instantiated at runtime (unless nested
  in a MovieClip),
• Can respond to Actionscript events (Mouse
  Presses, etc.) and run custom code.

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Graphic

• MovieClip lite no timeline,
• Cannot be added at runtime,
• Cannot be targeted/access through Actionscript
• i.e. cannot execute code.
• (Not particularly useful)

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Graphic Symbols

• Can contain nested MovieClips (which can be
  accessed via actionscript)
• Use where a static graphic object is required,
• Where the overhead of a MovieClip is not needed.

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Actionscript is

• The programming language exposed by Flash to
  interact with objects and respond to events,
• Object-oriented
• Classes, Inheritance, Polymorphism
• (Visually) Similar to Java or Javascript.
• Lets look at some Actionscript code

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• If you can read this then I should be showing you
  Actionscript code

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Writing Actionscript

• Three possible locations for Actionscript code

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Frame Scripts

• Created directly on a keyframe,
• Code is executed when playhead reaches a frame
  with a script.

Current playhead position
Keyframe with script
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Instance Code

• Code defined on a MovieClip instance

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External Actionscript File

• Associate MovieClip symbols with classes

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Variation Movieclip Frame Script

• Frame script applied to an instance of a MovieClip

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Problems with Instance Code and Nested Frame
Scripts

• Hard to locate,
• Relevant only for that instance,
• Multiple instances require individual code.
• Really, really hard to locate and maintain (like
  insane).
• All code must appear within an on handler
• on(lteventgt)do something

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How not to structure you files

• Show AS21.fla

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Movieclip Frame Scripts

• Code applied to library symbol,
• Code is shared amongst all instances.
• Code is still hard to find,
• Benefits of frame script with portability of
  instance script,

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External Actionscript File

• Recommended form of Actionscript programming.
• Text file with .as extension,
• Some functions only available in external .as
  files
• import statement,
• class keyword must use prototypes otherwise.
• Treat just like a Java class file.

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Resources

• Flash Libraries
• OSFlash Open Source Flash (http//www.osflash.or
  g)
• Colin Moock Flash Guru (http//www.moock.org/web
  design/flash/)
• ASwing Actionscript implementation of Swing GUI
  Framework (http//osflash.org/aswing)
• Layer51 Prototype (http//proto.layer51.com/)
• Senocular Object Prototypes (http//www.senocula
  r.com)
• Sephiroth Flash PHP Code (http//www.sephirot
  h.it/, http//www.sepy.it)

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Supporting Tools

• Other
• JSFL Javascript Flash interface
• Javascript control of the Flash IDE,
• Automate tedious batch operations (i.e. Updating
  the linkage for every MovieClip in the library),
• Refer to the JSFL entry in the Flash help index
  or visit http//dynamicflash.com/jsfl/
• Actionscript.org (http//www.actionscript.org)
• Forums and Flash tutorials.