User manual MACROMEDIA FLASH 8 - LEARNING ACTIONSCRIPT 2.0 IN FLASH

Learning ActionScript 2.0 in Flash Trademarks 1 Step RoboPDF, ActiveEdit, ActiveTest, Authorware, Blue Sky Software, Blue Sky, Breeze, Breezo, Captivate, Central, ColdFusion, Contribute, Database Explorer, Director, Dreamweaver, Fireworks, Flash, FlashCast, FlashHelp, Flash Lite, FlashPaper, Flash Video Encoder, Flex, Flex Builder, Fontographer, FreeHand, Generator, HomeSite, JRun, MacRecorder, Macromedia, MXML, RoboEngine, RoboHelp, RoboInfo, RoboPDF, Roundtrip, Roundtrip HTML, Shockwave, SoundEdit, Studio MX, UltraDev, and WebHelp are either registered trademarks or trademarks of Macromedia, Inc. and may be registered in the United States or in other jurisdictions including internationally. Other product names, logos, designs, titles, words, or phrases mentioned within this publication may be trademarks, service marks, or trade names of Macromedia, Inc. or other entities and may be registered in certain jurisdictions including internationally. Third-Party Information This guide contains links to third-party websites that are not under the control of Macromedia, and Macromedia is not responsible for the content on any linked site. If you access a third-party website mentioned in this guide, then you do so at your own risk. Macromedia provides these links only as a convenience, and the inclusion of the link does not imply that Macromedia endorses or accepts any responsibility for the content on those third-party sites. Speech compression and decompression technology licensed from Nellymoser, Inc. (www.nellymoser.com). SorensonTM SparkTM video compression and decompression technology licensed from Sorenson Media, Inc. Opera ® browser Copyright © 1995-2002 Opera Software ASA and its suppliers. All rights reserved. Macromedia Flash 8 video is powered by On2 TrueMotion video technology. © 1992-2005 On2 Technologies, Inc. All Rights Reserved. http://www.on2.com. Visual SourceSafe is a registered trademark or trademark of Microsoft Corporation in the United States and/or other countries. Copyright © 2005 Macromedia, Inc. All rights reserved. This manual may not be copied, photocopied, reproduced, translated, or converted to any electronic or machine-readable form in whole or in part without written approval from Macromedia, Inc. Notwithstanding the foregoing, the owner or authorized user of a valid copy of the software with which this manual was provided may print out one copy of this manual from an electronic version of this manual for the sole purpose of such owner or authorized user learning to use such software, provided that no part of this manual may be printed out, reproduced, distributed, resold, or transmitted for any other purposes, including, without limitation, commercial purposes, such as selling copies of this documentation or providing paid-for support services. Acknowledgments Project Management: Sheila McGinn Writing: Jen deHaan; Peter deHaan, Joey Lott Managing Editor: Rosana Francescato Lead Editor: Lisa Stanziano Editing: Linda Adler, Geta Carlson, Evelyn Eldridge, John Hammett, Mary Kraemer, Noreen Maher, Jessie Wood, Anne Szabla Production Management: Patrice O'Neill, Kristin Conradi, Yuko Yagi Media Design and Production: Adam Barnett, Aaron Begley, Paul Benkman. John Francis, Geeta Karmarkar, Masayo Noda, Paul Rangel, Arena Reed, Mario Reynoso Special thanks to Jody Bleyle, Mary Burger, Lisa Friendly, Stephanie Gowin, Bonnie Loo, Mary Ann Walsh, Erick Vera, the beta testers, and the entire Flash and Flash Player engineering and QA teams. First Edition: September 2005 Macromedia, Inc. 601 Townsend St. San Francisco, CA 94103 Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Intended audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 System requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Updating Flash XML files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 About the documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Additional resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Chapter 1: What's New in Flash 8 ActionScript . . . . . . . . . . . . . . 19 New in ActionScript 2.0 and Flash 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Changes to security model for locally installed SWF files. . . . . . . . . . 28 Chapter 2: Writing and Editing ActionScript 2.0 . . . . . . . . . . . . . 31 About ActionScript and events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Organizing ActionScript code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Using the Actions panel and Script window . . . . . . . . . . . . . . . . . . . . . . 35 About the Actions panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 About the Script window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 About coding in the Actions panel and Script window. . . . . . . . . . . . . 38 About Actions panel features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 About behaviors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 About ActionScript publish settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Chapter 3: About ActionScript . . . . . . . . . . . . . . . . . . . . . . . . . . . .67 What is ActionScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 About choosing between ActionScript 1.0 and ActionScript 2.0 . . . 69 Understanding ActionScript and Flash Player . . . . . . . . . . . . . . . . . . . .70 Chapter 4: Data and Data Types. . . . . . . . . . . . . . . . . . . . . . . . . . . 71 About data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 About data types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72 About variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Organizing data in objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108 About casting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 3 Chapter 5: Syntax and Language Fundamentals . . . . . . . . . . . . 113 About syntax, statements, and expressions . . . . . . . . . . . . . . . . . . . . . .114 About dot syntax and target paths. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 About language punctuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 About constants and keywords . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 About statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141 About arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 About operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 Chapter 6: Functions and Methods . . . . . . . . . . . . . . . . . . . . . . . 201 About functions and methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 Understanding methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .222 Chapter 7: Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 About object-oriented programming and Flash . . . . . . . . . . . . . . . . . .226 Writing custom class files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .235 About working with custom classes in an application . . . . . . . . . . . . .238 Example: Writing custom classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .263 Example: Using custom class files in Flash . . . . . . . . . . . . . . . . . . . . . . 276 Assigning a class to symbols in Flash . . . . . . . . . . . . . . . . . . . . . . . . . . .279 Compiling and exporting classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 Understanding classes and scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .283 About top-level and built-in classes . . . . . . . . . . . . . . . . . . . . . . . . . . . .286 About working with built-in classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . .296 Chapter 8: Inheritance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 About inheritance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 About writing subclasses in Flash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 Using polymorphism in an application . . . . . . . . . . . . . . . . . . . . . . . . . 308 Chapter 9: Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 About interfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 Creating interfaces as data types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318 Understanding inheritance and interfaces . . . . . . . . . . . . . . . . . . . . . . 320 Example: Using interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321 Example: Creating a complex interface . . . . . . . . . . . . . . . . . . . . . . . . .323 4 Contents Chapter 10: Handling Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329 Using event handler methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330 Using event listeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332 Using event listeners with components . . . . . . . . . . . . . . . . . . . . . . . . . 335 Using button and movie clip event handlers . . . . . . . . . . . . . . . . . . . . . 337 Broadcasting events from component instances . . . . . . . . . . . . . . . . 342 Creating movie clips with button states . . . . . . . . . . . . . . . . . . . . . . . . . 342 Event handler scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343 Scope of the this keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 Using the Delegate class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 Chapter 11: Working with Movie Clips. . . . . . . . . . . . . . . . . . . . . . 351 About controlling movie clips with ActionScript . . . . . . . . . . . . . . . . . 352 Calling multiple methods on a single movie clip . . . . . . . . . . . . . . . . . 354 Loading and unloading SWF files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355 Changing movie clip position and appearance . . . . . . . . . . . . . . . . . . 357 Dragging movie clips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359 Creating movie clips at runtime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 Adding parameters to dynamically created movie clips. . . . . . . . . . . 364 Managing movie clip depths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366 About caching and scrolling movie clips with ActionScript . . . . . . . 369 Using movie clips as masks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376 Handling movie clip events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 Assigning a class to a movie clip symbol. . . . . . . . . . . . . . . . . . . . . . . . 378 Initializing class properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 Chapter 12: Working with Text and Strings . . . . . . . . . . . . . . . . . 381 About text fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 About loading text and variables into text fields . . . . . . . . . . . . . . . . . 392 Using fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398 About font rendering and anti-alias text . . . . . . . . . . . . . . . . . . . . . . . . 406 About text layout and formatting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .414 Formatting text with Cascading Style Sheet styles . . . . . . . . . . . . . . .421 Using HTML-formatted text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436 Example: Creating scrolling text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449 About strings and the String class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450 Contents 5 Chapter 13: Animation, Filters, and Drawings. . . . . . . . . . . . . . 469 Scripting animation with ActionScript 2.0 . . . . . . . . . . . . . . . . . . . . . .470 About bitmap caching, scrolling, and performance . . . . . . . . . . . . . 480 About the Tween and TransitionManager classes . . . . . . . . . . . . . . . 481 Using filter effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 498 Working with filters using ActionScript . . . . . . . . . . . . . . . . . . . . . . . . 505 Manipulating filter effects with code . . . . . . . . . . . . . . . . . . . . . . . . . . . 530 Creating bitmaps with the BitmapData class . . . . . . . . . . . . . . . . . . . .534 About blending modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537 About operation order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540 Drawing with ActionScript. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540 Understanding scaling and slice guides . . . . . . . . . . . . . . . . . . . . . . . . .556 Chapter 14: Creating Interaction with ActionScript . . . . . . . . . . 561 About events and interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .562 Controlling SWF file playback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .562 Creating interactivity and visual effects . . . . . . . . . . . . . . . . . . . . . . . . .566 Creating runtime data bindings using ActionScript . . . . . . . . . . . . . . .579 Deconstructing a sample script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .588 Chapter 15: Working with Images, Sound, and Video . . . . . . . . 591 About loading and working with external media . . . . . . . . . . . . . . . . 592 Loading external SWF and image files. . . . . . . . . . . . . . . . . . . . . . . . . 593 About loading and using external MP3 files . . . . . . . . . . . . . . . . . . . . .598 Assigning linkage to assets in the library . . . . . . . . . . . . . . . . . . . . . . . 602 About using FLV video . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603 About creating progress animations for media files. . . . . . . . . . . . . . .624 Chapter 16: Working with External Data . . . . . . . . . . . . . . . . . . 633 Sending and loading variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .634 Using HTTP to connect to server-side scripts . . . . . . . . . . . . . . . . . . .638 About file uploading and downloading . . . . . . . . . . . . . . . . . . . . . . . . . 644 About XML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .652 Sending messages to and from Flash Player . . . . . . . . . . . . . . . . . . . .663 About the External API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 667 Chapter 17: Understanding Security. . . . . . . . . . . . . . . . . . . . . . .677 About compatibility with previous Flash Player security models . . . 677 About local file security and Flash Player. . . . . . . . . . . . . . . . . . . . . . . .679 About domains, cross-domain security, and SWF files . . . . . . . . . . 694 Server-side policy files for permitting access to data . . . . . . . . . . . . .702 HTTP to HTTPS protocol access between SWF files . . . . . . . . . . . . 707 6 Contents Chapter 18: Debugging Applications . . . . . . . . . . . . . . . . . . . . . . 711 Debugging your scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711 Using the Output panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 724 Chapter 19: Best Practices and Coding Conventions for ActionScript 2.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 731 Naming conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using comments in your code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ActionScript coding conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ActionScript and Flash Player optimization . . . . . . . . . . . . . . . . . . . . . Formatting ActionScript syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 732 742 745 762 764 Appendix A: Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . .773 Appendix B: Deprecated Flash 4 operators . . . . . . . . . . . . . . . 779 Appendix C: Keyboard Keys and Key Code Values . . . . . . . . . . 781 Appendix D: Writing Scripts for Earlier Versions of Flash Player . . . . . . . . . . . . . . . . . . . . . . . . . . .787 About targeting earlier versions of Flash Player . . . . . . . . . . . . . . . . . 787 Using Flash 8 to create content for Flash Player 4 . . . . . . . . . . . . . . 788 Appendix E: Object-Oriented Programming with ActionScript 1.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791 About ActionScript 1.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792 Creating a custom object in ActionScript 1.0 . . . . . . . . . . . . . . . . . . . . 794 Assigning methods to a custom object in ActionScript 1.0. . . . . . . . 795 Defining event handler methods in ActionScript 1.0 . . . . . . . . . . . . . 796 Creating inheritance in ActionScript 1.0 . . . . . . . . . . . . . . . . . . . . . . . . 798 Adding getter/setter properties to objects in ActionScript 1.0 . . . . . 800 Using Function object properties in ActionScript 1.0 . . . . . . . . . . . . . .801 Appendix F: Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 811 Contents 7 8 Contents Introduction Macromedia Flash Basic 8 and Macromedia Flash Professional 8 are the professional standard authoring tools for producing high-impact web experiences. ActionScript is the language you use to add interactivity to Flash applications, whether your applications are simple animated SWF files or more complex rich Internet applications. You don't have to use ActionScript to use Flash, but if you want to provide basic or complex user interactivity, work with objects other than those built into Flash (such as buttons and movie clips), or otherwise turn a SWF file into a more robust user experience, you'll probably want to use ActionScript. For more information, see the following topics: Intended audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Updating Flash XML files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 System requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 About the documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Additional resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Intended audience This manual assumes that you have already installed Flash Basic 8 or Flash Professional 8 and know how to use the user interface.You should know how to place objects on the Stage and manipulate them in the Flash authoring environment. If you have used a scripting language before, ActionScript will seem familiar. But if you're new to programming, ActionScript basics are easy to learn. You can start with simple commands and build more complexity as you progress. You can add a lot of interactivity to your files without having to learn (or write) a lot of code. 9 System requirements ActionScript 2.0 does not have any system requirements in addition to Flash 8. This manual assumes that you are using the default publishing settings for your Flash files: Flash Player 8 and ActionScript 2.0. If you change either of these settings, explanations and code samples in the documentation might not work correctly. If you develop applications for earlier versions of Flash Player, see Appendix D, "Writing Scripts for Earlier Versions of Flash Player," on page 787. Updating Flash XML files It is important that you always have the latest Flash XML files installed. Macromedia sometimes introduces features in dot releases (minor releases) of Flash Player. When such a release is available, you should update your version of Flash to get the latest XML files. Otherwise, the Flash 8 compiler might generate errors if you use new properties or methods that were unavailable in the version of Flash Player that came with your Flash installation. For example, Flash Player 7 (7.0.19.0) contained a new method for the System object, System.security.loadPolicyFile. To access this method, you must use the Player Updater installer to update all the Flash players that are installed with Flash. Otherwise, the Flash compiler displays errors. Remember that you can install a Player Updater that is one or more major versions ahead of your version of Flash. By doing this, you will get the XML files that you need but shouldn't have any compiler errors when you publish to older versions of Flash Player. Sometimes new methods or properties are available to older versions, and having the latest XML files minimizes the compiler errors you get when you try to access older methods or properties. About the documentation This manual provides an overview of ActionScript syntax and information on how to use ActionScript when working with different types of objects. For details on the syntax and usage of every language element, see the ActionScript 2.0 Language Reference. For more information, see the following topics: "Learning ActionScript 2.0 book overview" on page 11 "About the sample files" on page 14 "Terms used in this document" on page 13 "Copy and paste code" on page 13 10 Introduction Learning ActionScript 2.0 book overview The following list summarizes the contents of this manual: Chapter 1, "What's New in Flash 8 ActionScript," describes features that are new in ActionScript, changes to the compiler and debugger, and the new programming model for the ActionScript 2.0 language. Chapter 2, "Writing and Editing ActionScript 2.0," describes features of the ActionScript editor within Flash that make it easier to write code. Chapter 3, "About ActionScript," outlines what the ActionScript language is and details how to choose between which version of ActionScript to use. Chapter 4, "Data and Data Types," describes the terminology and basic concepts about data, data types, and variables. You use these concepts throughout the manual. Chapter 5, "Syntax and Language Fundamentals," describes the terminology and basic concepts of the ActionScript language. You use these concepts throughout the manual. Chapter 6, "Functions and Methods," describes how to write different kinds of functions and methods and how to use them in your application. Chapter 7, "Classes," describes how to create custom classes and objects in ActionScript. This chapter also lists the built-in classes in ActionScript and provides a brief overview of how you use them to access powerful features in ActionScript. Chapter 8, "Inheritance," describes inheritance in the ActionScript language and describes how to extend built-in or custom classes. Chapter 9, "Interfaces," describes how to create and work with interfaces in ActionScript. Chapter 10, "Handling Events," describes a few different ways to handle events: event handler methods, event listeners, and button and movie clip event handlers. Chapter 11, "Working with Movie Clips," describes movie clips and the ActionScript you can use to control them. Chapter 12, "Working with Text and Strings," describes the different ways you can control text and strings in Flash and includes information on text formatting and FlashType (advanced text rendering, such as anti-alias text). Chapter 13, "Animation, Filters, and Drawings," describes how to create code-based animation and images, add filters to objects, and draw using ActionScript. Chapter 14, "Creating Interaction with ActionScript," describes some simple ways in which you can create more interactive applications, including controlling when SWF files play, creating custom pointers, and creating sound controls. About the documentation 11 Chapter 15, "Working with Images, Sound, and Video," describes how to import external media files, such as bitmap images, MP3 files, Flash Video (FLV) files, and other SWF files, in your Flash applications. This chapter also provides an overview of how to work with video in your applications, and how to create progress bar loading animations. Chapter 16, "Working with External Data," describes how to process data from external sources using server- or client-side scripts in your applications. This chapter describes how to integrate data with your applications. Chapter 17, "Understanding Security," explains security in Flash Player, as it pertains to working with SWF files locally on your hard disk. This chapter also explains cross-domain security issues, and how to load data from servers, or across domains. Chapter 18, "Debugging Applications," describes the ActionScript debugger within Flash that makes it easier to write applications. Chapter 19, "Best Practices and Coding Conventions for ActionScript 2.0," explains the best practices for using Flash and writing ActionScript. This chapter also lists standardized coding conventions, such as naming variables, and other conventions. Appendix A, "Error Messages," lists the error messages that the Flash compiler can generate. Appendix B, "Deprecated Flash 4 operators," lists all the deprecated Flash 4 operators and their associativity. Appendix C, "Keyboard Keys and Key Code Values," lists all the keys on a standard keyboard and the corresponding ASCII key code values that are used to identify the keys in ActionScript. Appendix D, "Writing Scripts for Earlier Versions of Flash Player," provides guidelines to help you write scripts that are syntactically correct for the player version you are targeting. Appendix E, "Object-Oriented Programming with ActionScript 1.0," provides information on using the ActionScript 1.0 object model to write scripts. Appendix F, "Terminology," lists commonly used terminology when working with the ActionScript language and provides descriptions for the terms. This manual explains how to use the ActionScript language. For information on the language elements themselves, see the ActionScript 2.0 Language Reference. Typographical conventions This manual uses the following typographical conventions: Code font indicates ActionScript code. 12 Introduction Bold code font, typically within a procedure, indicates code that you need to modify or add to code you have already added to your FLA file. In some case, it might be used to highlight code to look at. Boldface text indicates data you need to type into the user interface, such as a filename or instance name. Italic text indicates a new term defined in the text that follows. In a file path, it might indicate a value that should be replaced (for example, with a directory name on your own hard disk). Terms used in this document The following terms are used in this manual: You refers to the developer who is writing a script or application. The user refers to the person who is running your scripts and applications. Compile time is the time at which you publish, export, test, or debug your document. Runtime is the time at which your script is running in Flash Player. ActionScript terms such as method and object are defined in Appendix F, "Terminology," on page 803. Copy and paste code When you paste ActionScript from the Help panel into your FLA or ActionScript file, you have to be careful about special characters. Special characters include special quotation marks (also called curly quotation marks or smart quotation marks). These characters are not interpreted by the ActionScript editor, so your code throws an error if you try to compile it in Flash. You can determine that your quotation mark characters are special characters if they do not color-code correctly. That is, if all your strings do not change in color in the code editor, you need to replace the special characters with regular straight quotation mark characters. If you type a single or double quotation mark character directly into the ActionScript editor, you always type a straight quotation mark character. The compiler (when you test or publish a SWF file) throws an error and lets you know if there are the wrong kind (special quotation marks or curly quotation marks) of characters in your code. You might also encounter special quotation marks if you paste ActionScript from other locations, such as a web page or a Microsoft Word document. N OT E About the documentation 13 Be cautious of proper line breaks when you copy and paste code. If you paste your code from some locations, the line of code might break in an improper location. Make sure that the color coding of your syntax is correct in the ActionScript editor if you think line breaks might be a problem. You might want to compare your code in the Actions panel to that in the Help panel to see if it matches. Try turning on Word Wrap in the ActionScript editor to help solve surplus line breaks in your code (select View > Word Wrap in the Script window, or Word Wrap from the Actions panel pop-up menu.) Additional resources In addition to this manual about ActionScript, there are manuals on other Flash topics, such as components and Macromedia Flash Lite. You can access each manual in the Help panel (Help > Flash Help), by viewing the default Table of Contents. Click the Clear button to see each manual that's available; for more information, see "Where to find documentation on other subjects" on page 17. For more information about other available resources, see the following topics: "About the sample files" on page 14 "Where to find PDF files or printed documentation" on page 15 "About LiveDocs" on page 15 "Additional online resources" on page 16 "Where to find documentation on other subjects" on page 17 About the sample files There are numerous ActionScript-based sample files available that install with Flash. These sample files show you how code works in a FLA file; this is often a useful learning tool. The chapters in this manual often reference these files, but we recommend that you also check out the sample files folder on your hard disk. The sample files include application FLA files that use common Flash functionality installed with Flash. These applications were designed to introduce new Flash developers to the capabilities of Flash applications, as well as show advanced developers how Flash features work in context. 14 Introduction You can find the ActionScript-focused sample source files in the Samples folder on your hard disk. In Windows, browse to boot drive\Program Files\Macromedia\Flash 8\ Samples and Tutorials\Samples\ActionScript\. On the Macintosh, browse to Macintosh HD/Applications/Macromedia Flash 8/ Samples and Tutorials/Samples/ActionScript/. You might find the following components-focused sample files useful, because they contain a lot of ActionScript code. They're also in the Samples folder on your hard disk: In Windows, browse to boot drive\Program Files\Macromedia\Flash 8\ Samples and Tutorials\Samples\Components\. On the Macintosh, browse to Macintosh HD/Applications/Macromedia Flash 8/ Samples and Tutorials/Samples/Components/. You can also find additional sample files for download on the Internet. The following web page contains links and descriptions of additional sample files: www.macromedia.com/go/ flash_samples/. Where to find PDF files or printed documentation If you prefer to read documentation in printed format, the PDF versions of each Help manual are available for downloading. Go to www.macromedia.com/support/documentation/ and select the product you're interested in. You can view or download the PDF or link to the LiveDocs version of the manual. Often, you can also purchase printed documentation. For updated information, go to the Documentation support site and select Flash Basic 8 or Flash Professional 8. About LiveDocs You can access documentation at the LiveDocs website, in addition to accessing it from the Help panel. The LiveDocs website contains all of the Flash Help pages and might contain comments that clarify, update, or correct parts of the documentation. Click View Comments on LiveDocs at the bottom of a page in the Help panel to display the equivalent page on the LiveDocs website. Go to http://livedocs.macromedia.com to see a list of all of the available documentation in the LiveDocs format. Additional resources 15 Technical writers monitor the LiveDocs website. One of the advantages of LiveDocs is seeing comments that clarify the documentation or correct any errata or issues that arise after a software release. LiveDocs is not the place to make help requests, such as asking questions about your code that doesn't work, comment on problems with software or installation, or ask how to create something with Flash. It is the correct place to provide feedback about the documentation (for example, you notice a sentence or paragraph that could be clarified). When you click the button to add a comment on LiveDocs, there are several points about the kinds of comments that are acceptable on the system. Please read these guidelines closely, or your comment might be removed from the website. If you have a question about Flash, please ask it on the Macromedia web forums: www.macromedia.com/support/forums/. The web forums are the best place to ask questions, because there are many Macromedia employees, Team Macromedia volunteers, Macromedia user group managers and members, and even technical writers who monitor these forums. Engineers do not monitor the LiveDocs system but do monitor the Flash wish list. If you think you have found a bug in the software, or you would like to request an enhancement to Flash, please fill out the wishform at www.macromedia.com/go/wish. If you report your bug or enhancement request on LiveDocs, it will not be officially added to the bug database. You must use the wishform instead, if you want an engineer to see your bug or request. Remember to be careful about special characters and line breaks when you paste from the web, including LiveDocs. Macromedia has made every effort to remove all special characters from code samples, but if you have problems pasting code, see "Copy and paste code" on page 13. Additional online resources There are several resources online that offer a wealth of instruction, help, and guidance to help you learn Macromedia Flash 8. Check the following websites often for updates: The Macromedia Developer Center website (www.macromedia.com/devnet) is updated regularly with the latest information on Flash, plus advice from expert users, advanced topics, examples, tips, tutorials (including multipart tutorials), and other updates. Check the website often for the latest news on Flash and how to get the most out of the program. The Macromedia Flash Support Center (www.macromedia.com/support/flash) provides TechNotes, documentation updates, and links to additional resources in the Flash community. The Macromedia Weblogs website (http://weblogs.macromedia.com) provides a list of both Macromedia employee and community weblogs (also known as blogs). 16 Introduction The Macromedia web forums (http://webforums.macromedia.com) provides numerous forums for asking specific questions about Flash, your applications, or the ActionScript language. The forums are monitored by Team Macromedia volunteers and often visited by Macromedia employees as well. If you're not sure where to go, or how to solve a problem, a Flash forum is a good place to start. The Macromedia Community website (www.macromedia.com/community) regularly hosts Macrochats, a series of live presentations on a variety of topics by Macromedia employees or community members. Check the website often for updates and to register for Macrochats. Where to find documentation on other subjects The following manuals offer additional information on subjects commonly associated with ActionScript 2.0: For information about the elements that compose the ActionScript language, see the ActionScript 2.0 Language Reference. For information about working in the Flash authoring environment, see How to Use Help. For information about working with components, see Using Components. Additional resources 17 18 Introduction CHAPTER 1 What's New in Flash 8 ActionScript Macromedia Flash Basic 8 and Macromedia Flash Professional 8 provide several enhancements that make it easy for you to write robust scripts using the ActionScript (AS) language. The new features, which are discussed in this chapter, include new language elements (see "Additions to the ActionScript language" on page 22), improved editing tools (see "ActionScript editing changes" on page 27), changes to the security model, and other ActionScript-related improvements to the authoring tool. For more information, see the following topics: New in ActionScript 2.0 and Flash 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Changes to security model for locally installed SWF files. . . . . . . . . . . . . . . . . . . . . . 28 1 New in ActionScript 2.0 and Flash 8 The ActionScript language has grown and developed since its introduction several years ago. With each new release of Flash, additional keywords, objects, methods, and other language elements were added to ActionScript. There are also ActionScript-related improvements to the Flash 8 authoring environments. Flash Basic 8 and Flash Professional 8 introduce several new language elements for expressive features, such as filters and blending modes, and application development, such as JavaScript integration (ExternalInterface) and file input and output (FileReference and FileReferenceList). This section provides an overview of the ActionScript language elements and classes that are new or changed in Flash 8 and ActionScript-related improvements to the authoring tool. For a list of specific additions to ActionScript 2.0, see "Additions to the ActionScript language" on page 22. To use any of the new language elements in your scripts, you must target Flash Player 8 (the default) when you publish your documents. 19 The following features were added to both Flash Basic 8 and Flash Professional 8 (unless noted otherwise): ActionScript editor enhancements let you show hidden characters in your scripts. For more information, see "Showing hidden characters" on page 53. Debug options are now available in the Script window, as well as the Actions panel, for ActionScript files. The Configuration directory that includes XML files and Class files is reorganized. See "Configuration files that install with Flash 8" on page 65 for details. You can set a preference to reload modified script files when working on an application, which helps you avoid working with older versions of script files, and overwriting newer script files. For more information, see "About ActionScript preferences" on page 42. The Script window feature is available in Flash Basic 8 and Flash Professional 8. That means you can now create an ActionScript file in either program. Script Assist (similar to Normal Mode in earlier editions of Flash) helps you code without needing to understand syntax. For more information on Script Assist, see "About Script Assist" on page 58. You can load new kinds of image files at runtime, which include progressive JPEG images, and non-animated GIF and PNG files. If you load an animated file, the first frame of the animation appears. You can assign linkage identifiers to bitmap and sound files stored in the Library, which means that you can attach images to the Stage or work with these assets in shared libraries. Bitmap caching lets you improve the performance of your applications at runtime by caching a bitmap representation of your instances. You can use ActionScript code to access this property. For more information, see "About bitmap caching, scrolling, and performance" on page 480. 9-slice scaling lets you scale movie clip instances without widening the strokes that outline the movie clip. You can use ActionScript code to access this feature in Flash Basic 8 and Flash Professional 8, or in the Flash 8 authoring tool. For more information, see "Working with 9-slice scaling in ActionScript" on page 558. For information about accessing 9-slice scaling in the authoring tool, see "About 9-slice scaling and movie clip symbols" on page 79 in Using Flash. You can now add metadata information to your FLA files in the Publish Settings dialog box. You can add a name and description to your FLA file using the dialog box to help increase online search visibility. The Strings panel is improved to include multiline support in the String field and a language XML file. For more information, see "About the Strings panel" on page 452. 20 What's New in Flash 8 ActionScript