On 13 Jan 2012, at 10:28, João Fernandes wrote:
Hi, I know that the code is not available yet but something that
bugs me
currently in the compiler is what is generated for getters and setters
Currently a public variable x will be generated as:
[Bindable(event="propertyChange")]
public function get x():int
{
return this._105x;
}
public function set x(value:int):void
{
var oldValue:Object=this._105x;
if (oldValue !== value)
{
this._105x=value;
if (this.hasEventListener("propertyChange"))
this
.dispatchEvent(mx.events.PropertyChangeEvent.createUpdateEvent(this,
"x", oldValue, value));
}
}
the problem with this approach is that each time 1 property in that
class
is changed and dispatches the propertyChangeEvent which forces all
getters
to be re-evaluated.
I can't comment on Alex's suggestions for the future, but I don't
think thats what happens in the current SDK?
If you create a getter/setter it only dispatches the
PropertyChangeEvent if you have marked it as being [Bindable], or if
you have marked the class as being [Bindable]. Omit these and it will
never dispatch a PropertyChangeEvent.
You can also very easy override this default binding functionality by
specifying a custom event in your
[Bindable(event="myCustomEventType")]. This means it is then up to you
to dispatch the event and it isolates this property from being mixed
in with other properties as they can all dispatch different events.
This is also more explicit as you can look in the code and see the
event you should listen for, iwhich if your adding the event listener
yourself is very useful (you should also use the [Event] metadata to
specify all the events that you class will dispatch for code hinting).
If you don't specify a custom event (which IMO is lazy), it still
shouldn't run all the getters, as when the PropertyChangeEvent is
caught, the value of 'event.property' is checked. If the string
matches the name of the property that the code it interested in, the
getter is invoked, if not, nothing happens (i.e. it doesn't force all
the getters to be re-evaluated).
Tink
