ADOBE FLEX Action Script Basics. MXML

Language Basics Action Script 3.0

Data Types  Primitive types var i:int = -1; var u:uint = 0;  Boolean, String  References var o:Object; var c:Class = String; var s:String = new c; var x:* = …

Action Script 3.0 Type System  Non-Strict typing vs Strict Typing var o:Object = …; var x:* = …  Classes are Objects (Array is Object) == true (int is Object) == true (Object is Object) == true (Class is Object) == true  Name of class x.className  Class from name var c:Class = getDefinitionByName(“Array”) as Class;

Action Script 3.0 Objects are Dynamic  Dynamic fields var o:Object = {name:"John", lname:"Smith"}; o.age = 23; o[“address”] = “New York”;  Dictionary vs Object as dictionary var d:Dictionary = new Dictionaty; var o:Object = new Object; d[“hello”] = 1; o[“hello”] = 1; d[o] = 2; o[o] = 2;

Action Script 3.0 Other Basic Types  Array var a:Array = new Array; var b:Array = [1,2,3];  concat, filter, for each, map, indexOf, length, pop, push, reverse, slice, sort, splice, shift, unshift  Array Collection  addItem, addItemAt, getItemAt, contains, setItemAt, toArray  Boolean  String

Action Script 3.0 Other Basic Types  String: the way we want it, but confusing sometimes  ==  …  length, indexOf, lastIndexOf, match, replace, slice, split, substr, charAr, charCodeAt, concat, search, toLowerCase, toUpperCase

Action Script 3.0 Basic Statements  if-then-else if ( ) else  for, while  for (var i:int = 0; i  for each (var o:Object in SomeArray)  for each (var t:SomeType in SomeArray)  Switch, break, try-catch, return, etc.

Action Script 3.0 Classes and methods  Classes class MyClass : extends yourClass { public function myMethod (i:int,j:int):int { return 0; } public override function yourFunction ():void {} }  No method overloading  Explicit overriding  super keyword, this keyword  public constructor

Action Script 3.0 Properties class MyClass { private var _myNumber:Number = 0; public function set myNumber (n:Number):void { _myNymber = n; //do something else } public function get myNumber ():Number { //do something else return _myNumber; }  Usage { var my:MyClass = new MyClass; my.myNumber = 5; }

Action Script 3.0 Static Methods class MyClass { private static var count:Number = 0; public static function getCount ():Number { return count++; } //… MyClass.getCount () == MyClass.getCount() + 1

Action Script 3.0 Inheritance  Single inheritance only  Multiple inheritance with Interfaces interface IMyInterface { public function myMethod ():Number; } class myClass extends YourClass implements IMyInterface, IYourInterface { //… }

Action Script 3.0 Tracing & Output  Integrated debugger  trace (…) function  Alert.show (…) method

Action Script 3.0 & XML var xml:XML = Ivan 2 Petyr 2 Stefan 2 Ivan ; trace(xml.student[0].name); trace(xml.student.length());

Execution Applications

Console application Program logic time Synchronous Input

Messages sent from Objects to Objects Events User Event (Button Click) Event Queue Dispatch event Internal Event (Timer) Registered Listener (Window) Handle event

Message Pump Program Logic External Events Internal Events

Frames Per Second Execution Time Limit Flex Application Execution Model time fames Function execution Manual dispatch Hander A Hander B Hander C Events

XML? Action Script? MXML

Motivation  Markup languages are common  Easier Maintenance of the Layout  Designers can work on the UI  Simplified access of language features

MXML What Happens  MyMXLExample.mxml: <mx:TextArea id=“myText” width = “100” height = “100”/>  This code is transformed to Action Script code class MyMXMLExample extends Application { public var myText:TextArea; //… some method { myText = new TextArea; myText.width = 100; myText.height = 100; }

Thank you!