Action script3 trace in flex builder - actionscript-3

Question

this is the code, i am using flex builder 4.5,
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600">
<fx:Declarations>
<!-- Place non-visual elements (e.g., services, value objects) here -->
</fx:Declarations>
<fx:Script>
<![CDATA[
public var ss:Array = ["a", "b", "c"];
trace(ss[0]);
public var str:String = "Good Luck";
trace(str);
]]>
</fx:Script>
</s:Application>
i get red cross next to trace statment and fault is
"1120:Access of defined property ss"
i have tried the commented line as well but no luck. i have tried with 3.5, 4.1 and 4.5 sdk.
Am i missing something? please guide!!
(i tried googling it but nothing came up )
thanks in advance.
(updated the code)

Answer 1

public var ss:String is a field declaration and trace(ss) is an action in code execution flow. Place trace(ss) in an appropriate scope (in a function aka method) and it will be compiled and executed without any problem.

Answer 2

I think you are getting confused between Class member properties and local variables. Inside a method, you can only declare local variables, for example:
public function debugString() : void {
// declare a local property, only this, 'debugString' function can acess
// or modify this property - it is deleted when this function finishes.
var myString : String = "Hello World";
trace(myString);
}
However, it would appear that you were trying to define Class member properties instead (because you were declaring the visibility of the property (ie: public)).
public class HelloWorld {
// Define a Class member property; all functions in this Class will be
// able to access, and modify it. This property will live for as long as the
// Class is still referenced.
public var myString : String = "Hello World";
public function debugString() : void {
// notice how we did not declare the 'myString' variable inside
// this function.
trace(myString);
}
}
Note that you can only access member properties once a Class has been constructed; so the earliest you can (sensibly) access them is in your Constructor, for example:
class HelloWorld {
public var myString : String = "Hello World";
// This will not work, because you can only access static properties
// outside of a function body. This makes sense because a member property
// belongs to each instance of a given Class, and you have not constructed
// that instance yet.
trace(myString);
// This is the Class Constructor, it will be called automatically when a
// new instance of the HelloWorld class is created.
public function HelloWorld() {
trace(myString);
}
}
What you might be trying to do is make use of a static property; these differ from Class member properties as they are Globally shared amongst all instances of a given class. By convention, static properties are defined in CAPS:
public class HelloWorld {
// Here we define a static property; this is accessible straight away and you
// don't even need to create a new instance of the host class in order to
// access it, for example, you can call HelloWorld.MY_STRING from anywhere in your
// application's codebase - ie: trace(HelloWorld.MY_STRING)
public static var MY_STRING : String = "Hello World";
}