Macromedia flex 2-migrating applications to flex 2 Manual De Usuario

52

Flex Classes

Enumerated values are now constants

In many cases, properties that took a predefined list of values (such as the Button control’s 

labelPlacement

 property taking 

right

, 

left

, 

bottom

, and 

top

) now take class constants as 

well. For example, the 

labelPlacement

 property can now take one of the following 

constants:

■

ButtonLabelPlacement.RIGHT

■

ButtonLabelPlacement.LEFT

■

ButtonLabelPlacement.BOTTOM

■

ButtonLabelPlacement.TOP

Other properties that now use constants include the Box control’s 

direction

 property; the 

Container control’s 

creationPolicy

, 

hScrollPolicy

, and 

vScrollPolicy

 properties, and 

the ProgressBar control’s 

direction

, 

labelPlacement

, and 

mode

 properties.

This change applies to ActionScript code. In general, the MXML usage has not changed.

life-cycle methods

The 

createChildren()

, 

childrenCreated()

, 

commitProperties()

, 

measure()

, and 

updateDisplayList()

 methods of UIComponent are now protected rather than public. 

These are component life-cycle methods that the framework calls, and which component 
developers must override, but they should not be called directly.

Flex 1.x:

override public function measure():void {

...

}

Flex 2:

override protected function measure():void {

...

}

mx.core.UIObject

The UIObject base class has been merged with the UIComponent class. UIComponent is 
now the lowest-level base class for nonskins. For information about changes to the combined 
object, see