Macromedia flex 2 Manual

Using ActionScript

29

You call the 

super()

 method within your constructor to invoke the superclass’s constructor to 

initialize the inherited items from the superclass. The 

super()

 method should be the first 

statement in your constructor; otherwise, the inherited parts of the superclass might not be 
properly constructed. In some cases, you might want to initialize your class first, and then call 

super()

. 

In the following example, you define a constructor that uses 

super()

 to call the superclass’s 

constructor: 

package myComponents
{

// Import necessary classes
import mx.core.Container;
import mx.controls.Button;
// Import all classes in the mx.events package
import mx.events.*;

// Class definition goes here.
public class MyButton extends Button {

// Define properties and methods.

}

}

NO

T

E

If you do not define a constructor, the compiler inserts one for you and adds a call to 

super()

. However, it is considered a best practice to write a constructor and to explicitly 

call 

super()

, unless the class contains nothing but static members. If you define the 

constructor, but omit the call to 

super()

, Flex automatically calls 

super()

 at the beginning 

of your constructor. 

NO

TE

You cannot define a constructor for an MXML component. For more information, see