AS3: Call function from one class to another - actionscript-3

Question

So i have two Class's Class A and Class B.
I have a function that i wish to use on Class A but my flash fla file is linked to Class B
So I have done the following:
Class A - the function
public function Fb_Checks()
{
// constructor code
load_top_bar();
}
Class B - import
import ClassA;
then if i try to call the function in Class A from Class B:
Fb_Checks();
I get the following error:
Call to a possibly undefined method Fb_Checks.
Is there something more i should be doing to get this to work?

Answer 1

You need to get more info about the OOP. How it is working then it will be easier to understand concepts.
For now simple explanation: We have ClassA, ClassB and ClassC:
ClassA
{
var value:ClassB;
public function ClassA ()
{
// each variable needs to initialize unless it is the ClassC, see below
// Only after that you will be able to reach the public properties
// of the class.
value = new ClassB();
value.calculate();
}
}
ClassB
{
var value:Number;
public function ClassB ()
{
}
public function calculate():void
{
// these must be statis
ClassC.sum(150, 450);
}
}
ClassC
{
// if the function is static, then you can call it without initializing
// the class
static public function sum(value1:Number, value2:Number):Number
{
return value1 + value2;
}
}

Answer 2

You'll have to make an instance of ClassA before you can call its public functions.
package
{
import ClassA;
public class ClassB
{
public function ClassB()
{
var instanceOfA:ClassA = new ClassA();
instanceOfA.Fb_Checks();
}
}
}
If you want to make it work like your example you should extend your ClassB with the ClassA. In that case it's public and protected functions are available in ClassB as well.
package
{
import ClassA;
public class ClassB extends ClassA
{
public function ClassB()
{
Fb_Checks();
}
}
}