tutorial 8 programming with actionscript 3.0. xp objectives review the basics of actionscript...

Tutorial 8

Programming with ActionScript 3.0

XPXPObjectives• Review the basics of ActionScript programming• Compare ActionScript 2.0 and ActionScript 3.0• Learn ActionScript 3.0 syntax• Write ActionScript 3.0 code to create functions

and handle events

New Perspectives on Adobe Flash CS3 2

XPXPObjectives• Create links to external Web sites• Create and test a Flash preloader• Create input and dynamic text fields• Create an input form


XPXPProgramming with ActionScript• ActionScript: programming language in Flash• ActionScript is used to make a document interactive– Examples: make buttons operational, process user input

• ActionScript may also be used to write applications• Tutorial tasks involving the use of ActionScript– Control multimedia elements to access Web pages– Process data entered into input forms


XPXPWorking with Objects and Properties• ActionScript is used to control and modify objects• Object: Flash element with modifiable properties– Examples: buttons, movie clips, and text blocks

• Properties are identified by underscore; e.g., _alpha• ActionScript examines and modifies many properties– Objects to be manipulated often require a name assignment

• Dot notation: links object to properties and methods– Example: circle_mc._alpha = 30 // mc stands for movie clip


XPXPUsing Actions, Methods, and Functions• Action: statement passing instruction to SWF file • Functions– Statement blocks that process data when called– Return a value or perform some action – Parameters or arguments: values passed to a function

• Methods are functions specific to a particular object– Use dot notation to bind a method to an object – Example: circle_mc.gotoAndPlay(10)


XPXPWriting ActionScript Code• Syntax: set of rules specifying valid code constructs• ActionScript statements follow a specific syntax – Example: parentheses are required to group arguments

• Use Actions toolbox to limit syntax errors• Some places where scripts are added:– Frame: script triggered when playhead reaches frame– Button: script activated when button clicked and released– Movie clip: script performed as part of a movie clip


XPXPWriting ActionScript Code

• Syntax: rules you must follow• Variable: container that holds data while SWF

plays• Keyword: word or phrase reserved for

ActionScript– Examples: else, if, while, this

• Event object: represents an actual event• Operators manipulate values in expressions


XPXPActionScript Syntax


XPXPAdding Events and Event Handling• Event source: object to which the event will

happen• Response: steps that are performed when the

event occurs• Event listener: method that the Flash Player

executes in response to specific events


XPXPAdding Comments• Comments are notes within the ActionScript

code that explain what is happening– Do not cause any actions to be performed


XPXPCreating Links to Web Sites• Objective: add links to a Resources page• URLRequest(): loads a document into a browser

window• Format: URLRequest(url)– URL (uniform resource locator): address of the Web

site

• Button clicks cause URLRequest () to load document


XPXPURLRequest() Class


XPXPUsing a Flash Preloader• SWF files are often downloaded to a client computer • Factors affecting the download time of SWF files– Size of the file measured in kilobytes– Type of Internet connection; e.g., broadband or dial-up

• Large SWF file may require a long time to download• Ways to overcome excessive download wait time:– Stream the content: play frames as content arrives– Add a preloader animation to advise user of status


XPXPExamples of Preloaders


XPXPCreating the Preloader• Adding a preloader requires ActionScript code• Pseudocode for the preloader logic– Get the total number of bytes– Get the number of bytes loaded– If the number of bytes loaded equals the total

number of bytes:• Play the rest of the SWF file

– Otherwise:• Continue playing the preloader animation


XPXPRectangle for Preloader Animation


XPXPCreating a Preloader for the Jackson’s Youth Sports Web Site• Objective: create a preloader on main page• Specifications for preloader– Add preloader to revised version of Main.fla file– Preloader will start Frame 1 of its own layer– ActionScript is added to second frame of Actions

layer


XPXPActionScript for Preloader


XPXPCreating an Input Form• How an input form works – User enters data into input fields– Input data processed by current page or Web server – Results of process are displayed

• One scenario involving an input form:– Visitor enters number and type of items to be

purchased– Other fields display total price based on entry

• Input forms must include dynamic text and input text


XPXPUsing Dynamic and Input Text• Static text: cannot be changed after document plays• Dynamic text: defined to display variable contents– Variable can be manipulated to change value displayed

• Use the Text tool to create a dynamic text block– Select Dynamic Text type in the Property inspector

• Input text: allows user to enter text into text block• Use Text tool to create an input text box– Select Input Text type in the Property inspector


XPXPInput Text Block Properties


XPXPUsing Dynamic and Input Text• Expression: statement assigning a value to a variable • Two types of data:– String data: series of characters within quotation

marks– Numeric data: numbers not enclosed with quotation

marks• Types of operators:– Assignment operator (=): assigns value to variable – Arithmetic operators: + , -, *, and /


XPXPCreating the Team Jersey Calculator Page• Objective: calculate costs for team jerseys• Calculator requirements:– Four input text boxes to gather type, quantity, add-ons– Calculate button with ActionScript to process input data – Dynamic text block to display the total cost– Explanatory text for input text and calculate button

• Pseudocode: programming logic in English syntax• Use pseudocode to design the script


XPXPComplete ActionScript Code


XPXPCreating the Team Jersey Calculator Page


XPXPAdding Numeric Feedback to the Preloader• Value in scaleX property of the rectangle can be

displayed as a percentage in a dynamic text block


tutorial 8 programming with actionscript 3.0. xp objectives review the basics of actionscript...

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