B.Sc. Multimedia ComputingMultimedia Authoring Introduction to ActionScript 3.0.
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Transcript of B.Sc. Multimedia ComputingMultimedia Authoring Introduction to ActionScript 3.0.
Agenda
Simple Types Variables Assignment Boolean Comparisons Control Structures Branching and Looping Introduction to Arrays
B.Sc. Multimedia ComputingMultimedia Authoring
Why Learn ActionScript ?
More control over movie clips and their properties Animate elements independently of the timeline Import and export data dynamically Dynamic control of sound and video Create objects that have physics-driven behaviors Personalize the user’s experience
B.Sc. Multimedia ComputingMultimedia Authoring
Structure and Syntax
Semicolons ; Curly Braces {} Code Blocks Dot Syntax ( for functions “methods”) Parenthesis Style
Script Spacing and Layout Comments
B.Sc. Multimedia ComputingMultimedia Authoring
ActionScript 3.0 Typing
Strict data typing aVariable = 5; // no type given, compiler error aVariable:Number = 5 // declare as being a number type
Case sensitive myValue not the same as myvalue
Class structures for custom objects
B.Sc. Multimedia ComputingMultimedia Authoring
Comments // this is a comment on one line
/* these are comments spanning more than one line*/
/* a script to calculate the area of a circle*/var area : Number; // holds the value of the areavar PI : Number = 3.142: // sets the value of PIvar radius :Number = 5 ; // sets the value of PIarea = PI * radius * radius // calculates the area and assigns it to the variable
B.Sc. Multimedia ComputingMultimedia Authoring
Semicolons ; and Braces {}
Semicolons separate statementsstatementOne;statementTwo;statementThree;
Curly braces define code blocks{statementOne;stateMentTwostatementThree}
B.Sc. Multimedia ComputingMultimedia Authoring
Operators
Binary + - * / Logical AND &&
(5 < 2) && (3 > 1) is False Logical OR ||
(5<2) || (3>1) is True Equalty <, >, <=, >= Assignment
a = 5
B.Sc. Multimedia ComputingMultimedia Authoring
Equality ==
a = ‘5’
x = 5
if (a == x) is True
a = 5
x = ‘6’
if (a == x) is False
B.Sc. Multimedia ComputingMultimedia Authoring
if statements
if(condition) {
statement(s);}e.g.var firstNumber:int = 25;var secondNumber:int = 39;
if(firstNumber==secondNumber){
trace("Snap!");}
B.Sc. Multimedia ComputingMultimedia Authoring
if..else
B.Sc. Multimedia ComputingMultimedia Authoring
var firstNumber:int = 25;var secondNumber:int = 39;
if(firstNumber==secondNumber){
trace("Snap!");}
else { trace("Not a match");}
switch
B.Sc. Multimedia ComputingMultimedia Authoring
var thisMonth:int = new Date().getMonth(); switch (thisMonth) {
case 0 : trace( "January"); break; case 1 : trace("February"); break; case 2 : trace( "March"); break; default: trace(“Some other month”);} // endSwitch
Looping: while
index = 4;while (index > 0){
// do something hereindex = index -1;// shorthand index --
}
B.Sc. Multimedia ComputingMultimedia Authoring
Looping: do while
int:index = 4;do {// do something here
index = index -1;// shorthand index --
} while (index > 0);
B.Sc. Multimedia ComputingMultimedia Authoring
How to Store Five NumbersUse individual variables for each number stored:
var numberOne:numbervar numberTwo:numbervar numberThree:numbervar numberFour:numbervar numberFive:number
messy - have to process as individual items ratherthan as a collection of grouped items. Solution - use an Array - contiguous data storage
B.Sc. Multimedia ComputingMultimedia Authoring
Arrays and Data Storage
B.Sc. Multimedia ComputingMultimedia Authoring
15
95
14
70
23
Elements
Size of the array is 5
The value stored at array element number 2 is 14
Array element numbering starts at 0
0
3
2
4
1
Arrays and Data Storage
B.Sc. Multimedia ComputingMultimedia Authoring
15
23
14
70
5
Array of numbers (integers)
Gibson
Fender
Punk
Martin
Array of strings
Les Paul
Declaring Arrays in Flash
B.Sc. Multimedia ComputingMultimedia Authoring
// create a new array
var numberArray:Array = new Array();
// store the numbers into the array// 15 95 14 70 23
numberArray[0] = 15;numberArray[1] = 95;numberArray[2] = 14;numberArray[3] = 70;numberArray[4] = 23;
Looping through an Array
B.Sc. Multimedia ComputingMultimedia Authoring
// total the numbers stored in the number array
var index:Number;var sum:Number;sum = 0;
for (index = 0; index <= 4; index = index + 1){sum = sum + numberArray[index]
}trace("The sum of the numbers in the array is " + sum)
Looping through an Array 2
B.Sc. Multimedia ComputingMultimedia Authoring
// total the numbers stored in the number array using array length method
var index:Number;var sum:Number;sum = 0;
for (index = 0; index < numberArray.length; index++){sum = sum + numberArray[index]
}trace("The sum of the numbers in the array is " + sum)