flex2 devguide

8/14/2019 flex2 devguide

1/1853

Flex2DevelopersGuide

Adobe

F

lex

2


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2006 Adobe Systems Incorporated. All rights reserved.

Flex 2 Developers Guide

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Adobe Systems Incorporated, 345 Park Avenue, San Jose, California 95110, USA

Notice to U.S. government end users. The software and documentation are Commercial Items, as that term is defined at 48C.F.R. 2.101, consisting of Commercial Computer Software and Commercial Computer Software Documentation, as suchterms are used in 48 C.F.R. 12.212 or 48 C.F.R. 227.7202, as applicable. Consistent with 48 C.F.R. 12.212 or 48 C.F.R.227.7202-1 through 227.7202-4, as applicable, the Commercial Computer Software and Commercial Computer SoftwareDocumentation are being licensed to U.S. Government end users (a) only as Commercial items and (b) with only those rights asare granted to all other end users pursuant to the terms and conditions herein. Unpublished-rights reserved under the copyrightlaws of the United States. Adobe Systems Incorporated, 345 Park Avenue, San Jose, CA 95110-2704, USA. For U.S.Government End Users, Adobe agrees to comply with all applicable equal opportunity laws including, if appropriate, theprovisions of Executive Order 11246, as amended, Section 402 of the Vietnam Era Veterans Readjustment Assistance Act of

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Contents

Chapter 1: About Flex Documentation . . . . . . . . . . . . . . . . . . . . . . 15

PART 1: USING FLEX PROGRAMMING LANGUAGES

Chapter 2: Developing Applications in MXML . . . . . . . . . . . . . . . 21

About MXML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Developing applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Chapter 3: MXML Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Basic MXML syntax. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Setting component properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Chapter 4: Using ActionScript . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Using ActionScript in Flex applications. . . . . . . . . . . . . . . . . . . . . . . . . . 55

Working with Flex components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Comparing, including, and importing ActionScript code. . . . . . . . . . . 68

Techniques for separating ActionScript from MXML . . . . . . . . . . . . . .72Creating ActionScript components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75

Performing object introspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Chapter 5: Using Events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83

About events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Using events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87

Manually dispatching events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109

Event propagation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Event priorities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Using event subclasses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

About keyboard events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
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PART 2: BUILDING USER INTERFACES FOR FLEX APPLICA-TIONS

Chapter 6: Using Flex Visual Components . . . . . . . . . . . . . . . . . 133

About visual components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Class hierarchy for visual components . . . . . . . . . . . . . . . . . . . . . . . . . . 134

Using the UIComponent class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

Sizing visual components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141

Handling events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

Using styles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151

Using behaviors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Applying skins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

Changing the appearance of a component at run time . . . . . . . . . . . . 155

Extending components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

Chapter 7: Using Data Providers and Collections. . . . . . . . . . . . 161

About data providers and collections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

Using IList interface methods and properties . . . . . . . . . . . . . . . . . . . . 174

Using ICollectionView interface methods and properties. . . . . . . . . . 176

Using events and update notifications . . . . . . . . . . . . . . . . . . . . . . . . . . 189

Using hierarchical data providers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

Using remote data providers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

Chapter 8: Sizing and Positioning Components . . . . . . . . . . . . . 221

About sizing and positioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

Sizing components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .228Positioning and laying out controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . .248

Using constraint-based layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .255

Chapter 9: Using Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

About controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260

Working with controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .266

Button control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .269

PopUpButton control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

ButtonBar and ToggleButtonBar controls . . . . . . . . . . . . . . . . . . . . . .276

LinkBar control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

TabBar control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .283CheckBox control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .287

RadioButton control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .288

NumericStepper control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294

DateChooser and DateField controls . . . . . . . . . . . . . . . . . . . . . . . . . . .296


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LinkButton control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307

HSlider and VSlider controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .310

SWFLoader control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

Image control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325

VideoDisplay control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335

ColorPicker control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342

Alert control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .351

ProgressBar control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356

HRule and VRule controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .361

ScrollBar control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365

Chapter 10: Using Text Controls . . . . . . . . . . . . . . . . . . . . . . . . . 369

About text controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

Using the text property . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371

Using the htmlText property. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376

Selecting and modifying text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387

Label control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392

TextInput control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393

Text control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395

TextArea control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397

RichTextEditor control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398

Chapter 11: Using Menu-Based Controls . . . . . . . . . . . . . . . . . . 407

About menu-based controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407

Defining menu structure and data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408

Handling menu-based control events . . . . . . . . . . . . . . . . . . . . . . . . . . .415

Menu control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427

MenuBar control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .431

PopUpMenuButton control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433

Chapter 12: Using Data-Driven Controls . . . . . . . . . . . . . . . . . . 439

List control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440

HorizontalList control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450

TileList control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454

ComboBox control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458

DataGrid control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467

Tree control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479

Chapter 13: Introducing Containers . . . . . . . . . . . . . . . . . . . . . . .491

About containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .491

Using containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493


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Using scroll bars. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .507

Using Flex coordinates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510

Creating and managing component instances at run time. . . . . . . . . 516

Chapter 14: Using the Application Container . . . . . . . . . . . . . . 529

Using the Application container . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529

About the Application object. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537

Showing the download progress of an application . . . . . . . . . . . . . . 542

Chapter 15: Using Layout Containers. . . . . . . . . . . . . . . . . . . . . 553

About layout containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554

Canvas layout container. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554

Box, HBox, and VBox layout containers . . . . . . . . . . . . . . . . . . . . . . . 559

ControlBar layout container . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .562

ApplicationControlBar layout container . . . . . . . . . . . . . . . . . . . . . . . . .564DividedBox, HDividedBox, and VDividedBox layout containers . . .567

Form, FormHeading, and FormItem layout containers. . . . . . . . . . . .570

Grid layout container. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594

Panel layout container . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601

Tile layout container . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 606

TitleWindow layout container . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609

Chapter 16: Using Navigator Containers . . . . . . . . . . . . . . . . . . .627

About navigator containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .627

ViewStack navigator container. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .628

TabNavigator container . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .634Accordion navigator container . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .639

PART 3: CUSTOMIZING THE USER INTERFACE

Chapter 17: Using Behaviors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649

About behaviors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649

Applying behaviors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659

Working with effects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 674

Chapter 18: Using Styles and Themes . . . . . . . . . . . . . . . . . . . . .697

About styles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .697

Using external style sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 726

Using local style definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 727

Using the StyleManager class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .730


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Using the setStyle() and getStyle() methods . . . . . . . . . . . . . . . . . . . . 737

Using inline styles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 742

Loading style sheets at run time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744

Using filters in Flex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 753

About themes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 756

Chapter 19: Using Fonts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763

About fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763

Using device fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766

Using embedded fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 767

Using multiple typefaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 781

About the font managers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786

Setting character ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786

Embedding double-byte fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789

Embedding fonts from SWF files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802

Chapter 20: Using Skins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805

About skinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805

Graphical skinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 807

Using SWF files as skins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .814

Programmatic skinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .816

Creating themes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 849

Chapter 21: Using Item Renderers and Item Editors. . . . . . . . . . 851

About item renderers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 851Creating an item renderer and item editor. . . . . . . . . . . . . . . . . . . . . . . 860

Creating drop-in item renderers and item editors . . . . . . . . . . . . . . . . 870

Creating inline item renderers and editors . . . . . . . . . . . . . . . . . . . . . . 875

Creating item renderers and item editor components . . . . . . . . . . . . 883

Working with item renderers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 892

Chapter 22: Working with Item Editors . . . . . . . . . . . . . . . . . . . 903

The cell editing process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903

Creating an editable cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904

Returning data from an item editor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905

Sizing and positioning an item editor . . . . . . . . . . . . . . . . . . . . . . . . . . . 909Making an item editor that responds to the Enter key . . . . . . . . . . . . . 911

Using the cell editing events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .912

Item editor examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 920

Examples using item editors with the list controls . . . . . . . . . . . . . . . . 934


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Chapter 23: Using ToolTips. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 943

About ToolTips. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 943

Creating ToolTips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 944

Using the ToolTip Manager. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 952

Using error tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .962

Chapter 24: Using the Cursor Manager. . . . . . . . . . . . . . . . . . . .967

About the Cursor Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .967

Using the Cursor Manager. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .968

Creating and removing a cursor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 969

Using a busy cursor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .970

Chapter 25: Localizing Flex Applications . . . . . . . . . . . . . . . . . 975

About localized Flex applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .975

Creating a localized application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .976

PART 4: FLEX PROGRAMMING TOPICS

Chapter 26: Dynamically Repeating Controls and Containers 995

About Repeater components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 995

Using the Repeater component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 996

Considerations when using a Repeater component . . . . . . . . . . . . . 1017

Chapter 27: Using View States. . . . . . . . . . . . . . . . . . . . . . . . . . 1019

About view states . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1019

Defining and applying view states . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1022

Building applications by using view states . . . . . . . . . . . . . . . . . . . . . .1045

Creating your own override classes. . . . . . . . . . . . . . . . . . . . . . . . . . . .1048

Chapter 28: Using Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . 1051

About transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1051

Defining transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1053

Handling events when using transitions . . . . . . . . . . . . . . . . . . . . . . . .1060

Using action effects in a transition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1061

Filtering effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1065

Transition tips and troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1077

Chapter 29: Using the Drag and Drop Manager. . . . . . . . . . . . 1081

About the Drag and Drop Manager. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1081

Using drag-and-drop with list-based controls . . . . . . . . . . . . . . . . . .1082

Manually adding drag-and-drop support . . . . . . . . . . . . . . . . . . . . . . .1090

Programming a drag-and-drop operation . . . . . . . . . . . . . . . . . . . . . . 1098


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Drag-and-drop techniques and considerations. . . . . . . . . . . . . . . . . .1109

Chapter 30: Embedding Assets . . . . . . . . . . . . . . . . . . . . . . . . . .1113

About embedding assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1113Syntax for embedding assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1116

Embedding asset types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1121

Chapter 31: Creating Modular Applications. . . . . . . . . . . . . . . . .1131

Modular applications overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1131

Creating modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1134

Compiling modules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1135

Loading and unloading modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1136

Using ModuleLoader events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1140

Chapter 32: Using the History Manager . . . . . . . . . . . . . . . . . . 1147About history management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1148

Using standard history management . . . . . . . . . . . . . . . . . . . . . . . . . . . 1148

Using custom history management . . . . . . . . . . . . . . . . . . . . . . . . . . . .1150

How the HistoryManager class saves and loads states. . . . . . . . . . . 1156

Using history management in a custom wrapper . . . . . . . . . . . . . . . . 1157

Chapter 33: Printing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1161

About printing by using Flex classes . . . . . . . . . . . . . . . . . . . . . . . . . . . 1162

Using the FlexPrintJob class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1162

Using a print-specific output format . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1167

Printing multipage output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1171

Chapter 34: Communicating with the Wrapper . . . . . . . . . . . . .1181

About exchanging data with Flex applications. . . . . . . . . . . . . . . . . . . 1181

Passing request data to Flex applications. . . . . . . . . . . . . . . . . . . . . . . 1186

Accessing JavaScript functions from Flex . . . . . . . . . . . . . . . . . . . . . . 1192

Accessing Flex from JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1205

About ExternalInterface API security in Flex . . . . . . . . . . . . . . . . . . . . 1211

Chapter 35: Using Shared Objects. . . . . . . . . . . . . . . . . . . . . . . 1213

About shared objects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1213

Creating a shared object. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1215

Destroying shared objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1217

SharedObject example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1217


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Chapter 36: Creating Accessible Applications . . . . . . . . . . . . . 1219

Accessibility overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1219

About screen reader technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1221

Configuring Flex applications for accessibility . . . . . . . . . . . . . . . . . .1223Accessible components and containers. . . . . . . . . . . . . . . . . . . . . . . . 1224

Creating tab order and reading order . . . . . . . . . . . . . . . . . . . . . . . . . . 1227

Creating accessibility with ActionScript . . . . . . . . . . . . . . . . . . . . . . . . 1232

Accessibility for hearing-impaired users. . . . . . . . . . . . . . . . . . . . . . . . 1233

Testing accessible content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1233

PART 5: FLEX DATA FEATURES

Chapter 37: Representing Data . . . . . . . . . . . . . . . . . . . . . . . . . 1237

About data representation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1237

Chapter 38: Binding Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1245

About data binding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1245

Binding data with curly braces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1247

Binding data with the tag. . . . . . . . . . . . . . . . . . . . . . . . . 1252

About the binding mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1258

Using binding for moving related data . . . . . . . . . . . . . . . . . . . . . . . . . 1266

Chapter 39: Storing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1269

About data models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1269

Defining a data model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1270Specifying an external source for an tag or tag . .1274

Using validators with a data model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1276

Using a data model as a value object . . . . . . . . . . . . . . . . . . . . . . . . . . 1277

Binding data into an XML data model . . . . . . . . . . . . . . . . . . . . . . . . . 1279

Chapter 40: Validating Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1281

Validating data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1281

Using validators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1286

General guidelines for validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1303

Working with validation errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1306Working with validation events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1310

Using standard validators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1313


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Chapter 41: Formatting Data . . . . . . . . . . . . . . . . . . . . . . . . . . . .1327

Using formatters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1327

Writing an error handler function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1329

Using the standard formatters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1331

PART 6: DATA ACCESS AND INTERCONNECTIVITY

Chapter 42: Accessing Server-Side Data . . . . . . . . . . . . . . . . 1345

About Flex data access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1345

About RPC services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1346

About the Data Management Service . . . . . . . . . . . . . . . . . . . . . . . . . 1348

About messaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1349

Using Flex Data Services with Flex Builder . . . . . . . . . . . . . . . . . . . . 1349

Chapter 43: Configuring Data Services . . . . . . . . . . . . . . . . . . . 1351

About service configuration files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1352

Configuring message channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1360

Serializing data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1366

Securing destinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1379

Configuring server-side service logging . . . . . . . . . . . . . . . . . . . . . . . 1384

Working with session data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1387

Using software clustering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1388

Managing services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1390

Using custom error handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1392

About Data Services class loading. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1394

Using the factory mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1396

Chapter 44: Understanding RPC Components. . . . . . . . . . . . 1399

About RPC components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1399

Comparing the Flex RPC services feature to other technologies . 1403

Chapter 45: Using RPC Components. . . . . . . . . . . . . . . . . . . . .1407

Declaring an RPC component. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1407

Configuring a destination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1411

Calling a service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1413

Setting properties for RemoteObject methods or WebService opera-tions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1424

Handling service results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1428

Using a service with binding, validation, and event listeners . . . . . 1438

Handling asynchronous calls to services . . . . . . . . . . . . . . . . . . . . . . 1439


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Using features specific to RemoteObject components . . . . . . . . . .1442

Using features specific to WebService components . . . . . . . . . . . .1444

Chapter 46: Configuring RPC Services. . . . . . . . . . . . . . . . . . . 1451

Understanding destination configuration. . . . . . . . . . . . . . . . . . . . . . . 1451

Configuring destination properties . . . . . . . . . . . . . . . . . . . . . . . . . . . .1454

Configuring the Proxy Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1457

Chapter 47: Understanding Flex Messaging. . . . . . . . . . . . . . .1459

About messaging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1459

Understanding the Flex messaging architecture . . . . . . . . . . . . . . . . 1461

Chapter 48: Using Flex Messaging . . . . . . . . . . . . . . . . . . . . . .1465

Using messaging in a Flex application . . . . . . . . . . . . . . . . . . . . . . . . .1465

Working with Producer components . . . . . . . . . . . . . . . . . . . . . . . . . .1466Working with Consumer components . . . . . . . . . . . . . . . . . . . . . . . . . 1472

Using subtopics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1476

Using a pair of Producer and Consumer components in an application .1480

Chapter 49: Configuring the Message Service. . . . . . . . . . . . . 1483

Understanding Message Service configuration . . . . . . . . . . . . . . . . . 1483

Configuring Message Service destinations . . . . . . . . . . . . . . . . . . . . . 1486

Creating a custom Message Service adapter . . . . . . . . . . . . . . . . . . .1494

Chapter 50: Understanding the Flex Data Management Service. .1497

About the Data Management Service feature. . . . . . . . . . . . . . . . . . . 1497

Chapter 51: Distributing Data in Flex Applications. . . . . . . . . . 1501

Creating a distributed data application . . . . . . . . . . . . . . . . . . . . . . . . . 1501

Mapping client-side objects to Java objects . . . . . . . . . . . . . . . . . . . . 1510

Handling data synchronization conflicts. . . . . . . . . . . . . . . . . . . . . . . . 1514

Chapter 52: Configuring the Data Management Service . . . . 1517

About Data Management Service configuration . . . . . . . . . . . . . . . . 1518

Configuring Data Management Service destinations . . . . . . . . . . . .1520

Working with data adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1525

Managing hierarchical collections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1556

Pushing data changes from the server to clients . . . . . . . . . . . . . . . .1569


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PART 7: CHARTING COMPONENTS

Chapter 53: Introduction to Charts. . . . . . . . . . . . . . . . . . . . . . .1573

About charting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1573Using the charting controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1575

About the axes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1583

About charting events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1584

Creating charts in ActionScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1585

Defining chart data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1592

Chapter 54: Chart Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1623

Using area charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1624

Using bar charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1627

Using bubble charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1629

Using candlestick charts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1631Using column charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1635

Using HighLowOpenClose charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1642

Using line charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1646

Using pie charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1657

Using plot charts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1667

Using multiple data series. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1671

Using multiple axes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1673

Chapter 55: Formatting Charts. . . . . . . . . . . . . . . . . . . . . . . . . . 1681

Applying chart styles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1682

Adding ChartElement objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1690Setting padding properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1693

Working with axes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1698

Using strokes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1728

Using fills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1735

Using filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1747

Adding grid lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1753

Using DataTips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1761

Skinning ChartItem objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1773

Using Legend controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1781

Stacking charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1793

Chapter 56: Using Events and Effects in Charts. . . . . . . . . . . . 1801

Handling user interactions with charts. . . . . . . . . . . . . . . . . . . . . . . . . . 1801

Using effects with charts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1819


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Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i


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1CHAPTER 1

About Flex Documentation

Flex 2 Developers Guideprovides the tools for you to develop Internet applications by using

Adobe Flex 2. This book is intended for application developers who are learning Flex or

want to extended their Flex programming knowledge. It provides a solid grounding in the

tools that Flex provides to develop applications.

Contents

Using this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Accessing the Flex documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Using this manualThis manual can help anyone who is developing Flex applications. However, this manual is

most useful if you have basic experience using Flex, or have read Getting Started with Flex 2.

Getting Started with Flex 2provides an introduction to Flex and helps you develop the basic

knowledge that makes using this manual easier.Flex 2 Developers Guideis divided into the following parts:

Part Description

Part 1, Using Flex Programming

Languages

Describes how to use MXML and ActionScript.

Part 2, Building User Interfaces

for Flex Applications

Describes how to use Flex components to build the user

interface to your application.

Part 3, Customizing the User

Interface

Describes how to improve the user experience by adding

additional functionality to your application.

Part 4, Flex ProgrammingTopics

Describes some advanced programming techniques thatyou can use to make your applications more interactive

and expressive.


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16 About Flex Documentation

Accessing the Flex documentationThe Flex documentation is designed to provide support for the complete spectrum of

participants.

Documentation set

The Flex documentation set includes the following titles:

Part 5, Flex Data Features Describes how to use Flex data representation and data

features.

Part 6, Data Access and

Interconnectivity

Describes the Flex features that let you work with

external data. IncludesAdobe Flex Data Servicesfeatures.

Part 7, Charting Components Describes how to use charting components.

Book Description

Flex 2 Developers Guide Describes how to develop your dynamic web

applications.

Getting Started with Flex 2 Contains an overview of Flex features and application

development procedures.

Building and Deploying Flex 2

Applications

Describes how to build and deploy Flex applications.

Creating and Extending Flex 2

Components

Describes how to create and extend Flex components.

Migrating Applications to Flex 2 Provides an overview of the migration process, as well as

detailed descriptions of changes in Flex and

ActionScript.

Using Flex Builder 2 Contains comprehensive information about all Adobe

Flex Builder 2 features, for every level of Flex Builder

users.

Adobe Flex 2 Language Reference Provides descriptions, syntax, usage, and code

examples for the Flex API.

Part Description


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Typographical conventions 17

Viewing online documentation

All Flex documentation is available online in HTML and Adobe Portable Document Format

(PDF) files from theAdobewebsite. It is also available from the Adobe Flex Builder Help

menu.

Typographical conventionsThe following typographical conventions are used in this book:

Italic fontindicates a value that should be replaced (for example, in a folder path).

Code fontindicates code.

Code font italic indicates a parameter.

Boldface font indicates a verbatim entry.
http://www.adobe.com/go/flex_documentationhttp://www.adobe.com/go/flex_documentation


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18 About Flex Documentation


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19

1PART 1

Using Flex ProgrammingLanguages

This part describes how to use MXML and ActionScript, the Adobe Flex 2

programming languages.

The following topics are included:

Chapter 2: Developing Applications in MXML . . . . . . . . . . . . . . . . 21

Chapter 3: MXML Syntax. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Chapter 4: Using ActionScript. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Chapter 5: Using Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83


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21

2CHAPTER 2

Developing Applicationsin MXML

MXML is an XML language that you use to lay out user-interface components for Adobe Flex

applications. You also use MXML to declaratively define nonvisual aspects of an application,

such as access to server-side data sources and data bindings between user-interface

components and server-side data sources. This topic describes MXML and how you use

MXML to develop Flex applications.For information on MXML syntax, see Chapter 3, MXML Syntax, on page 41.

Contents

About MXML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Developing applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

About MXMLYou use two languages to write Flex applications: MXML and ActionScript. MXML is an

XML markup language that you use to lay out user-interface components. You also useMXML to declaratively define nonvisual aspects of an application, such as access to data

sources on the server and data bindings between user-interface components and data sources

on the server.

Like HTML, MXML provides tags that define user interfaces. MXML will seem very familiar

if you have worked with HTML. However, MXML is more structured than HTML, and it

provides a much richer tag set. For example, MXML includes tags for visual components such

as data grids, trees, tab navigators, accordions, and menus, as well as nonvisual components

that provide web service connections, data binding, and animation effects. You can also

extend MXML with custom components that you reference as MXML tags.

One of the biggest differences between MXML and HTML is that MXML-definedapplications are compiled into SWF files and rendered by Adobe Flash Player, which

provides a richer and more dynamic user interface than page-based HTML applications

provide.


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22 Developing Applications in MXML

You can write an MXML application in a single file or in multiple files. MXML also supports

custom components written in MXML and ActionScript files.

Writing a simple applicationBecause MXML files are ordinary XML files, you have a wide choice of development

environments. You can write MXML code in a simple text editor, a dedicated XML editor, or

an integrated development environment (IDE) that supports text editing. Flex supplies a

dedicated IDE, called Adobe Flex Builder, that you can use to develop your applications.

The following example shows a simple Hello World application that contains just an

tag and two child tags, the tag and the tag. The

tag defines theApplication container that is always the root tag of a Flex

application. The tag defines a Panel container that includes a title bar, a title, a

status message, a border, and a content area for its children. The tag represents aLabel control, a very simple user interface component that displays text.

Save this code to a file named hello.mxml. MXML filenames must end in a lowercase .mxml

file extension.

The following image shows the Hello World application rendered in a web browser

window:


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About MXML 23

About XML encoding

The first line of the document specifies an optional declaration of the XML version. It is good

practice to include encoding information that specifies how the MXML file is encoded. Many

editors let you select from a range of file encoding options. On North American operatingsystems, ISO-8859-1 is the dominant encoding format, and most programs use that format

by default. You can use the UTF-8 encoding format to ensure maximum platform

compatibility. UTF-8 provides a unique number for every character in a file, and it is

platform-, program-, and language-independent. If you specify an encoding format, it must

match the file encoding you use. The following example shows an XML declaration tag that

specifies the UTF-8 encoding format:

About the tag

In addition to being the root tag of a Flex application, the tag representsanApplication container. Acontaineris a user-interface component that contains other

components and has built-in layout rules for positioning its child components. By default, an

Application container lays out its children vertically from top to bottom. You can nest other

types of containers inside an Application container, such as the Panel container shown above,

to position user-interface components according to other rules. For more information, see

Chapter 6, Using Flex Visual Components, on page 133.

About MXML tag properties

The properties of an MXML tag, such as the text, fontWeight, and fontSize properties of

the tag, let you declaratively configure the initial state of the component. You

can use ActionScript code in an tag to change the state of a component at run

time. For more information, see Chapter 4, Using ActionScript, on page 55.

Compiling MXML to SWF Files

You can deploy your application as a compiled SWF file or, if you have Adobe Flex Data

Services, you can deploy your application as a set of MXML and AS files.

If you are using Flex Builder, you compile and run the compiled SWF file from within Flex

Builder. After your application executes correctly, you deploy it by copying it to a directory on

your web server or application server. Users then access the deployed SWF file by making anHTTP request in the form:

http://hostname/path/filename.swf


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24 Developing Applications inMXML

The Flex also provides a command-line MXML compiler, mxmlc, that lets you compile

MXML files. You can use mxmlc to compile hello.mxml from a command line, as the

following example shows:

cd flexInstallDir/binmxmlc --show-actionscript-warnings=true --strict=true

c:/appDir/hello.mxml

In this example,flexInstallDiris the Flex installation directory, and appDiris the directory

containing hello.mxml. The resultant SWF file, hello.swf, is written to the same directory as

hello.mxml.

For more information about mxmlc, see Chapter 9, Using the Flex Compilers, in Building

and Deploying Flex 2 Applications. For more information about the debugger version of Flash

Player, see Chapter 11, Logging, in Building and Deploying Flex 2 Applications.

The relationship of MXML tags to ActionScriptclasses

Adobe implemented Flex as an ActionScript class library. That class library contains

components (containers and controls), manager classes, data-service classes, and classes for all

other features. You develop applications by using the MXML and ActionScript languages with

the class library.

MXML tags correspond to ActionScript classes or properties of classes. Flex parses MXML

tags and compiles a SWF file that contains the corresponding ActionScript objects. For

example, Flex provides the ActionScript Button class that defines the Flex Button control. In

MXML, you create a Button control by using the following MXML statement:

When you declare a control using an MXML tag, you create an instance object of that class.

This MXML statement creates a Button object, and initializes the label property of the

Button object to the string Submit.

An MXML tag that corresponds to an ActionScript class uses the same naming conventions as

the ActionScript class. Class names begin with an uppercase letter, and uppercase letters

separate the words in class names. Every MXML tag attribute corresponds to a property of the

ActionScript object, a style applied to the object, or an event listener for the object. For a

complete description of the Flex class library and MXML tag syntax, see theAdobe Flex 2

Language Reference.
http://../buildapps/compilers.pdfhttp://../buildapps/logging.pdfhttp://../buildapps/logging.pdfhttp://../buildapps/compilers.pdf


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Developing applications 25

Understanding a Flex application structure

You can write an MXML application in a single file or in multiple files. You typically define a

main file that contains the tag. From within your main file, you can then

reference additional files written in MXML, ActionScript, or a combination of the two

languages.

A common coding practice is to divide your Flex application into functional units, or

modules, where watch module performs a discrete task. In Flex, you can divide your

application into separate MXML files and ActionScript files, where each file corresponds to a

different module. By dividing your application into modules you provide many benefits,

including the following:

Ease of development Different developers or development groups can develop and debug

modules independently of each other.

Reusability You can reuse modules in different application so that you do not have toduplicate your work.

Maintainability You can isolate and debug errors faster than you could if you application

was developed in a single file.

In Flex, a module corresponds to a custom component implement either in MXML or in

ActionScript. These custom components can reference other custom components. There is no

restriction on the level of nesting of component references in Flex. You define your

components as required by your application.

Developing applicationsMXML development is based on the same iterative process used for other types of webapplication files such as HTML, JavaServer Pages (JSP), Active Server Pages (ASP), and

ColdFusion Markup Language (CFML). Developing a useful Flex application is as easy as

opening your favorite text editor, typing some XML tags, saving the file, requesting the files

URL in a web browser, and then repeating the same process.

Flex also provides tools for code debugging; for more information, see Chapter 12, Using the

Command-Line Debugger, in Building and Deploying Flex 2 Applications.
http://../buildapps/debugging.pdfhttp://../buildapps/debugging.pdfhttp://../buildapps/debugging.pdfhttp://../buildapps/debugging.pdf


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Laying out a user interface using containers

In the Flex model-view design pattern, user interface components represent the view. The

MXML language supports two types of user interface components: controls and containers.

Controls are form elements, such as buttons, text fields, and list boxes. Containers are

rectangular regions of the screen that contain controls and other containers.

You use container components for laying out a user interface, and for controlling user

navigation through the application. Examples of layout containers include the HBox

container for laying out child components horizontally, the VBox container for laying out

child components vertically, and the Grid container for laying out child components in rows

and columns. Examples of navigator containers include the TabNavigator container for

creating tabbed panels, the Accordion navigator container for creating collapsible panels, and

the ViewStacknavigator container for laying out panels on top of each other.

The Container class is the base class of all Flex container classes. Containers that extend the

Container class add their own functionality for laying out child components. Typical

properties of a container tag include id, width, and height. For more information about the

standard Flex containers, see Chapter 13, Introducing Containers, on page 491.

The following image shows an example Flex application that contains a List control on the left

side of the user interface and a TabNavigator container on the right side. Both controls are

enclosed in a Panel container:

Use the following code to implement this application:

List control TabNavigator container

Panel container


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Item 1Item 2Item 3

The List control and TabNavigator container are laid out side by side because they are in an

HBox container. The controls in the TabNavigator container are laid out from top to bottom

because they are in a VBox container.

For more information about laying out user-interface components, see Chapter 6, Using Flex

Visual Components, on page 133.

Adding user interface controls

Flex includes a large selection of user interface components, such as Button, TextInput, and

ComboBox controls. After you define the layout and navigation of your application by using

container components, you add the user interface controls.

The following example contains an HBox (horizontal box) container with two child controls,

a TextInput control and a Button control. An HBox container lays out its children

horizontally.


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Typical properties of a control tag include id, width, height, fontSize, color, event

listeners for events such as click and change, and effect triggers such as showEffect androllOverEffect. For information about the standard Flex controls, see Chapter 9, Using

Controls, on page 259.

Using the id property with MXML tags

With a few exceptions (see MXML tag rules on page 54), an MXML tag has an optional id

property, which must be unique within the MXML file. If a tag has an id property, you can

reference the corresponding object in ActionScript.

In the following example, results from a web service request are traced in the writeToLog

function:

...

trace(myText.text);}

]]>

This code causes the MXML compiler to autogenerate a public variable named myText that

contains a reference to that TextInput instance. This autogenerated variable lets you access the

component instance in ActionScript. You can explicitly refer to the TextInput controls

instance with its id instance reference in any ActionScript class or script block. By referring to

a components instance, you can modify its properties and call its methods.

Because each id value in an MXML file is unique, all objects in a file are part of the same flat

namespace. You do not qualify an object by referencing its parent with dot notation, as in

myVBox.myText.text.For more information, see Referring to Flex components on page 60.


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Using XML namespaces

In an XML document, tags are associated with a namespace. XML namespaces let you refer to

more than one set of XML tags in the same XML document. The xmlns property in an

MXML tag specifies an XML namespace. To use the default namespace, specify no prefix. To

use additional tags, specify a tag prefix and a namespace. For example, the xmlns property in

the following tag indicates that tags in the MXML namespace use the

prefix mx:. The Universal Resource Identifier (URI) for the MXML namespace is http://

www.adobe.com/2006/mxml.

XML namespaces give you the ability to use custom tags that are not in the MXML

namespace. The following example shows an application that contains a custom tag called

CustomBox. The namespace value containers.boxes.* indicates that an MXML

component called CustomBox is in the containers/boxes directory.

The containers/boxes directory can be a subdirectory of the directory that contains the

application file, or it can be a subdirectory of one of the ActionScript source path directoriesassigned in the flex-config.xml file. If copies of the same file exist in both places, Flex uses the

file in the application file directory. The prefix name is arbitrary, but it must be used as

declared.

When using a component contained in a SWC file, the package name and the namespace

must match, even though the SWC file is in the same directory as the MXML file that uses it.

A SWC file is an archive file for Flex components. SWC files make it easy to exchange

components among Flex developers. You need only exchange a single file, rather than the

MXML or ActionScript files and images and other resource files. Also, the SWF file inside a

SWC file is compiled, which means that the code is obfuscated from casual view. For more

information on SWC files, see Chapter 9, Using the Flex Compilers, in Building andDeploying Flex 2 Applications.
http://../buildapps/compilers.pdfhttp://../buildapps/compilers.pdf


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Using MXML to trigger run-time code

Flex applications are driven by run-time events, such as when a user selects a Button control.

You can specifyevent listeners, which consist of code for handling run-time events, in the event

properties of MXML tags. For example, the tag has a click event property in

which you can specify ActionScript code that executes when the Button control is clicked at

run time. You can specify simple event listener code directly in event properties. To use more

complex code, you can specify the name of an ActionScript function defined in an

tag.

The following example shows an application that contains a Button control and a TextArea

control. The click property of the Button control contains a simple event listener that sets

the value of the TextArea controls text property to the text Hello World.

The following image shows the application rendered in a web browser window:

The following example shows the code for a version of the application in which the event

listener is contained in an ActionScript function in an tag:

private function hello():void {textarea1.text="Hello World";}

]]>


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For more information about using ActionScript with MXML, see Chapter 4, Using

ActionScript, on page 55.

Binding data between components

Flex provides simple syntax for binding the properties of components to each other. In the

following example, the value inside the curly braces ({ }) binds the text property of a

TextArea control to the text property of a TextInput control. When the applicationinitializes, both controls display the text Hello. When the user clicks the Button control, both

controls display the text Goodbye.

The following image shows the application rendered in a web browser window after the user

clicks the Submit button:

As an alternative to the curly braces ({ }) syntax, you can use the tag, in which

you specify the source and destination of a binding. For more information about data

binding, see Chapter 39, Storing Data, on page 1269.


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Using RPC services

Remote-procedure-call (RPC) services let your application interact with remote servers to

provide data to your applications, or for your application to send data to a server.

Flex is designed to interact with several types of RPC services that provide access to local and

remote server-side logic. For example, a Flex application can connect to a web service that uses

the Simple Object Access Protocol (SOAP), a Java object residing on the same application

server as Flex using AMF, or an HTTP URL that returns XML. AMF is the protocol used in

Flash Remoting MX.

The MXML components that provide data access are called RPC components. MXML

includes the following types of RPC components:

WebService provides access to SOAP-based web services

HTTPService provides access to HTTP URLs that return data

RemoteObject provides access to Java objects using the AMF protocol (Flex Data Servicesonly)

The following example shows an application that calls a web service that provides weather

information, and displays the current temperature for a given ZIP code. The application

binds the ZIP code that a user enters in a TextInput control to a web service input parameter.

It binds the current temperature value contained in the web service result to a TextArea

control.

{zip.text}


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For more information about using RPC services, see Chapter 44, Understanding RPCComponents, on page 1399.

Storing data in a data model

You can use a data model to store application-specific data. Adata modelis an ActionScript

object that provides properties for storing data, and optionally contains methods for

additional functionality. Data models provide a way to store data in the Flex application

before it is sent to the server, or to store data sent from the server before using it in the

application.


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You can declare a simple data model that does not require methods in an ,

, or tag. The following example shows an application that contains

TextInput controls for entering personal contact information and a data model, represented

by the tag, for storing the contact information:

{homePhoneInput.text}{cellPhoneInput.text}{emailInput.text}

Validating dataYou can use validator components to validate data stored in a data model, or in a Flex user-

interface component. Flex includes a set of standard validator components. You can also

create your own.

The following example uses validator components for validating that the expected type of data

is entered in the TextInput fields. Validation is triggered automatically when the users edits a

TextInput control. If validation fails, the user receives immediate visual feedback.


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{homePhoneInput.text}{cellPhoneInput.text}{emailInput.text}


For more information about using data models, see Chapter 39, Storing Data, on

page 1269. For more information on validators, see Chapter 40, Validating Data, on

page 1281.

Formatting data

Formatter components are ActionScript components that perform a one-way conversion of

raw data to a formatted string. They are triggered just before data is displayed in a text field.

Flex includes a set of standard formatters. You can also create your own formatters. Thefollowing example shows an application that uses the standard ZipCodeFormatter component

to format the value of a variable:


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]]>


For more information about formatter components, see Chapter 41, Formatting Data, on

page 1327.

Using Cascading Style Sheets (CSS)

You can use style sheets based on the Cascading Style Sheets (CSS) standard to declare stylesto Flex components. The MXML tag contains inline style definitions or a

reference to an external file that contains style definitions.

The tag must be an immediate child of the root tag of the MXML file. You can

apply styles to an individual component using a class selector, or to all components of a

certain type using a type selector.

The following example defines a class selector and a type selector in the tag. Both

the class selector and the type selector are applied to the Button control:

.myClass { color: Red } /* class selector */Button { font-size: 18pt} /* type selector */


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A class selector in a style definition, defined as a label preceded by a period, defines a new

named style, such as myClass in the preceding example. After you define it, you can apply the

style to any component using the styleName property. In the preceding example, you apply

the style to the Button control to set the font color to red.

A type selector applies a style to all instances of a particular component type. In the preceding

example, you set the font size for all Button controls to 18 points.


For more information about using Cascading Style Sheets, see Chapter 18, Using Styles and

Themes, on page 697.

Using skins

Skinningis the process of changing the appearance of a component by modifying or replacing

its graphical elements. These graphical elements can be made up of images or the output of

drawing API methods. They are known as symbols. You can reskin Flex components without

changing their functionality. A file that contains new skins for use in your Flex applications is

known as a theme.

There are two types of skins in Flex: graphical and programmatic. Graphical skinsare Adobe

Flash symbols that you can change directly in the Macromedia Flash Professional 8 from

Adobe authoring environment. You drawprogrammatic skinsby using ActionScript

statements and define these skins in class files. Sometimes it is more advantageous to reskin a

component graphically, and in some cases it makes more sense to reskin a component

programmatically. You cannot combine graphical and programmatic skins in a single theme

file.

For more information about using skins, see Chapter 20, Using Skins, on page 805.


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Using effects

An effectis a change to a component that occurs over a brief period of time. Examples of

effects are fading, resizing, and moving a component. An effect is combined with a trigger,

such as a mouse click on a component, a component getting focus, or a component becoming

visible, to form a behavior. In MXML, you apply effects as properties of a control or container.

Flex provides a set of built-in effects with default properties.

The following example shows an application that contains a Button control with its

rollOverEffect property set to use theWipeLeft effect when the user moves the mouse over

it:

For more information about effects, see Chapter 17, Using Behaviors, on page 649.

Defining custom MXML components

Custom MXML components are MXML files that you create and use as custom MXML tags

in other MXML files. They encapsulate and extend the functionality of existing Flex

components. Just like MXML application files, MXML component files can contain a mix of

MXML tags and ActionScript code. The name of the MXML file becomes the class name

with which you refer to the component in another MXML file.

The following example shows a custom ComboBox control that is prepopulated with list

items:

NOTE

You cannot access custom MXML component URLs directly in a web browser.


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DogsCatsMice

The following example shows an application that uses the MyComboBox component as a

custom tag. The value * assigns the localnamespace to the current directory.


For more information about MXML components, see Chapter 7, Creating Simple MXML

Components, in Creating and Extending Flex 2 Components.

You can also define custom Flex components in ActionScript. For more information, see

Chapter 9, Creating Simple Visual Components in ActionScript, in Creating and Extending

Flex 2 Components.
http://../createcomps/mxmlcomponents.pdfhttp://../createcomps/mxmlcomponents.pdfhttp://../createcomps/ascomponents.pdfhttp://../createcomps/mxmlcomponents.pdfhttp://../createcomps/mxmlcomponents.pdfhttp://../createcomps/ascomponents.pdf


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41

3CHAPTER 3

MXML Syntax

MXML is an XML language that you use to lay out user-interface components for Adobe Flex

applications. This topic describes basic MXML syntax.

Contents

Basic MXML syntax. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Setting component properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Basic MXML syntaxMost MXML tags correspond to ActionScript 3.0 classes or properties of classes. Flex parses

MXML tags and compiles a SWF file that contains the corresponding ActionScript objects.

ActionScript 3.0 uses syntax based on the ECMAScript edition 4 draft language specification.

ActionScript 3.0 includes the following features:

Formal class definition syntax

Formal packages structure

Typing of variables, parameters, and return values (compile-time only)

Implicit getters and setters that use the get and set keywords

Inheritance

Public and private members

Static members

Cast operator

For more information about ActionScript 3.0, see Chapter 7, Using ActionScript, on

page 91.
http://../getstarted/usingas.pdfhttp://../getstarted/usingas.pdfhttp://../getstarted/usingas.pdfhttp://../getstarted/usingas.pdf


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42 MXML Syntax

Naming MXML files

MXML filenames must adhere to the following naming conventions:

Filenames must be valid ActionScript identifiers, which means they must start with aletter or underscore character (_), and they can only contain letters and numbers and

underscore characters after that.

Filenames must not be the same as ActionScript class names, component id values, or the

word application. Do not use filenames that match the names of MXML tags that are in

the mx namespace.

Filenames must end with a lowercase .mxml file extension.

Using tags that represent ActionScript classes

An MXML tag that corresponds to an ActionScript class uses the same naming conventions as

the ActionScript class. Class names begin with a capital letter, and capital letters separate the

words in class names. For example, when a tag corresponds to an ActionScript class, its

properties correspond to the properties and events of that class.

Setting component propertiesIn MXML, a component property uses the same naming conventions as the corresponding

ActionScript property. A property names begins with a lowercase letter, and capital letters

separate words in the property names.

You can set most component properties as tag attributes, in the form:

You can set all component properties as child tags, in the form:

5025Hello World

You often use child tags when setting the value of a property to a complex Object because it is

not possible to specify a complex Object as the value of tag attribute. In the following

example, you use child tags to set the data provider of a ComboBox control of an

ArrayCollection object:

AK


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Setting component properties 43

ALAR

The one restriction on setting properties that use child tags is that the namespace prefix of a

child tag, mx: in the previous example, must match the namespace prefix of the component

tag.

Each of a components properties is one of the following types:

Scalar properties, such as a number or string

Array of scalar values, such as an array of numbers or strings

ActionScript object

Array of ActionScript objects

ActionScript properties XML data

Adobe recommends that you assign scalar values using tag attributes, and that you assign

complex types, such as ActionScript objects, by using child tags.

Setting scalar properties

You usually specify the value of a scalar property as a property of a component tag, as the

following example shows:

Setting properties using constants

The valid values of many component properties are defined by static constants, where these

static constants are defined in an ActionScript class. In MXML, you can either use the static

constant to set the property value, or use the value of the static constant, as the following

example shows:

...

...


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44 MXML Syntax

The HBox container defines a property named horizontalScrollPolicy which defines the

operation of the containers horizontal scroll bar. In this example, you explicitly set the

horizontalScrollPolicy property to disable the horizontal scroll bar.

In the first example, you set the horizontalScrollPolicy property using a static constantnamed OFF, which is defined in the ScrollPolicy class. In MXML, you must use data binding

syntax when setting a property value to a static constant. The advantage of using the static

constant is that the Flex compiler recognizes incorrect property values, and issues an error

message at compile time.

Alternatively, you can set the value of the horizontalScrollPolicy property to the value of

the static constant. The value of the OFF static constant is "off". When you use the value of

the static constant to set the property value, the Flex compiler cannot determine if you used

an unsupported value. If you incorrectly set the property, you will not know until you get a

run-time error.

In ActionScript, you should always use static constants to set property values, as the followingexample shows:

var myHBox:HBox = new HBox();myHBox.horizontalScrollPolicy=ScrollPolicy.OFF;

Setting the default property

Many Flex components define a single default property. The default propertyis the MXML tag

property that is implicit for content inside of the MXML tag if you do not explicitly specify a

property. For example, consider the following MXML tag definition:

anything here

If this tag defines a default property named default_property, the preceding tag definition

is equivalent to the following code:

anything here

It is also equivalent to the following code:


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The default property provides a shorthand mechanism for setting a single property. For a

ComboBox, the default property is the dataProvider property. Therefore the two

ComboBox definitions in the following code are equivalent:

AKALAR

AKALAR

Not all Flex components define a default property. SeeAdobe Flex 2 Language Referencefor

each component to determine its default property.

You can also define a default property when you create a custom component. For moreinformation, see Chapter 5, Using Metadata Tags in Custom Components, in Creating and

Extending Flex 2 Components.

Escaping characters using the backslash character

When setting a property value in MXML, you can escape a reserved character by prefixing it

with the backslash character, \, as the following example shows:
http://../createcomps/metadata.pdfhttp://../createcomps/metadata.pdf


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46 MXML Syntax

In this example, you want to use literal curly brace characters ({ }) in a text string. But Flex

uses curly braces to indicate a data binding operation. Therefore, you prefix each curly brace

with the backslash character to cause the MXML compiler to interpret them as literal

characters.

Setting String properties using the backslashcharacter

The MXML compiler automatically escapes the backslash character in MXML when the

character is part of the value specified to a property of type String. Therefore, it always

converts "\" to "\\".

This is necessary because the ActionScript compiler recognizes "\\" as the character sequence

for a literal "\" character, and strips out the leading backslash when it initializes the property

value.

Including a newline character in a String value

For properties of type String, you can insert a newline character in the String in two ways:

By inserting the code in your String value in MXML

By inserting "\n" in an ActionScript String variable used to initialize the MXML property

To use the code to insert a newline character, include that code in the property value inMXML, as the following example shows:

To use an ActionScript String variable to insert a newline character, create an ActionScript

variable, and then use data binding to set the property in MXML, as the following example

shows:

[Bindable]public var myText:String = "Display" + "\n" + "Content";

]]>

In this example, you set the text property of the TextArea control to a value that includes a

newline character.

NOTE

Do not use the backslash character (\) as a separator in the path to an application asset.

You should always use a forward slash character (/) as the separator.


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Notice that this example includes the [Bindable] metadata tag before the property

definition. This metadata tag specifies that the myText property can be used as the source of a

data binding expression. Data binding automatically copies the value of a source property of

one object to the destination property of another object at run time when the sourceproperty changes.

If you omit this metadata tag, the compiler issues a warning message specifying that the

property cannot be used as the source for data binding. For more information, see Chapter

38, Binding Data, on page 1245.

Setting Arrays of scalar values

When a class has a property that takes an Array as its value, you can represent the property in

MXML using child tags. The component in the following example has a dataProvider

property that contains an Array of numbers:

940621485053402

The and tags around the Array elements are optional. Therefore,

you can also write this example as the following example shows:

940621485053402

In this example, since the data type of the dataProvider property is defined as Array, Flex

automatically converts the three number definitions into a three-element array.

Component developers may have specified additional information within the component

definition that defines the data type of the Array elements. For example, if the developer

specified that the dataProvider property only supports String elements, then this examplewould cause a compiler error because you specified numbers to it. TheAdobe Flex 2 Language

Referencedocuments the Array properties that define a required data type for the Array

elements.


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48 MXML Syntax

Setting Object properties

When a component has a property that takes an object as its value, you can represent the

property in MXML using a child tag with tag attributes, as the following example shows:

The following example shows an ActionScript class that defines an Address object. This object

is used as a property of the PurchaseOrder component in the next example.

class Address{

public var name:String;public var street:String;

public var city:String;public var state:String;public var zip:Number;

}

The following example shows an ActionScript class that defines a Purcha

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