ActionScript Reference Guide
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Acknowledgments
Director: Erick Vera
Project Management: Stephanie Gowin, Barbara Nelson
Writing: Jody Bleyle, Mary Burger, Kim Diezel, Stephanie Gowin, Dan Harris, Barbara Herbert, Barbara Nelson, Shirley Ong,
Tim Statler
Managing Editor: Rosana Francescato
Editing: Linda Adler, Mary Ferguson, Mary Kraemer, Noreen Maher, Antonio Padial, Lisa Stanziano, Anne Szabla
Production Management: Patrice O’Neill
Media Design and Production: Adam Barnett, Christopher Basmajian, Aaron Begley, John Francis, Jeff Harmon
First Edition: Septermber 2003
Macromedia, Inc.
600 Townsend St.
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3
CONTENTS
INTRODUCTION: Getting Started with ActionScript . . . . . . . . . . . . . . . . . . . . . . . 9
Intended audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
System requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Using the documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Typographical conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Terms used in this document. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Additional resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
PART I: Welcome to ActionScript
CHAPTER 1: What’s New in Flash MX 2004 ActionScript. . . . . . . . . . . . . . . . . . 13
New and changed language elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
New security model and legacy SWF files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Porting existing scripts to Flash Player 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
ActionScript editor changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Debugging changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
New object-oriented programming model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
CHAPTER 2: ActionScript Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Differences between ActionScript and JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . 25
Unicode support for ActionScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
About data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Assigning data types to elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
About variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Using operators to manipulate values in expressions . . . . . . . . . . . . . . . . . . . . . . . 45
Specifying an object’s path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Using built-in functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Creating functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4 Contents
CHAPTER 3: Writing and Debugging Scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Controlling when ActionScript runs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Using the Actions panel and Script window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Using the ActionScript editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Debugging your scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Using the Output panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Updating Flash Player for testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
PART II: Handling Events and Creating Interaction
CHAPTER 4: Handling Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Using event handler methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Using event listeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Using button and movie clip event handlers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Creating movie clips with button states . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Event handler scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Scope of the “this” keyword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
CHAPTER 5: Creating Interaction with ActionScript . . . . . . . . . . . . . . . . . . . . . . 91
About events and interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Controlling SWF file playback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Creating interactivity and visual effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Deconstructing a sample script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
PART III: Working with Objects and Classes
CHAPTER 6: Using the Built-In Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
About classes and instances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Overview of built-in classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
CHAPTER 7: Working with Movie Clips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
About controlling movie clips with ActionScript . . . . . . . . . . . . . . . . . . . . . . . . . 121
Calling multiple methods on a single movie clip . . . . . . . . . . . . . . . . . . . . . . . . . 122
Loading and unloading additional SWF files. . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Specifying a root Timeline for loaded SWF files . . . . . . . . . . . . . . . . . . . . . . . . . 123
Loading JPEG files into movie clips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Changing movie clip position and appearance. . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Dragging movie clips. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Creating movie clips at runtime. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Adding parameters to dynamically created movie clips . . . . . . . . . . . . . . . . . . . . 128
Managing movie clip depths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Drawing shapes with ActionScript. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Using movie clips as masks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Contents 5
Handling movie clip events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Assigning a class to a movie clip symbol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Initializing class properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
CHAPTER 8: Working with Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Using the TextField class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Creating text fields at runtime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Using the TextFormat class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Formatting text with Cascading Style Sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Using HTML-formatted text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Creating scrolling text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
CHAPTER 9: Creating Classes with ActionScript 2.0 . . . . . . . . . . . . . . . . . . . . 155
Principles of object-oriented programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Using classes: a simple example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Creating and using classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Instance and class members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
Creating and using interfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
Understanding the classpath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Using packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Importing classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Implicit get/set methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
Creating dynamic classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
How classes are compiled and exported . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
PART IV: Working with External Data and Media
CHAPTER 10: Working with External Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
Sending and loading variables to and from a remote source. . . . . . . . . . . . . . . . . 177
Sending messages to and from Flash Player . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Flash Player security features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
CHAPTER 11: Working with External Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Overview of loading external media. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Loading external SWF and JPEG files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Loading external MP3 files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Reading ID3 tags in MP3 files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
Playing back external FLV files dynamically . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Preloading external media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
