OK, thanks.
That reading and your examples cleared things up. I never declare
functions dynamically like these examples (they're always methods
defined on a class), and I definitely never nest function creation.
One thing I do often do (for instance in a "createChildren" function
is create a local variable (to be used as a child object), add some
event listener, and then add it to the parent. Is code like this ok?
class foo extends HBox
{
function createChildren():void
{
var oBtn:Button = new Button();
oBtn.addEventListener("click",onBtnClick);
this.addChild(oBtn);
// now you're saying I should null my locals...?
oBtn=null;
}
function onBtnClick(event:MouseEvent):void
{
// do whatever
}
} // end class foo
I know for ActionScript 3 there were some changes to do with adding
event listeners, and I've never had any problems with the scope of my
functions; they always seem to have the scope of the object they're
defined in.
thanks,
Thunder
--- In [email protected], "JesterXL" <[EMAIL PROTECTED]> wrote:
>
> Negative, local variables are good, and optimized in Flash Player 7.
Use
> them. This discussion is getting more boilerplate code than it
should, but
> if you want to know the details, I can elaborate.
>
> Back in Flash Player 6, MovieClips got the option to have event
handlers
> attached to them. That is also back when functions were executed in
the
> scope they were defined when called that way. Thus:
>
> function myOnPress()
> {
> }
>
> my_mc.onPress = myOnPress;
>
> the myOnPress function would run scoped to my_mc, not in relation to
the
> class myOnPress was defined. This was more pronounced in data
classes like
> XML:
>
> function init()
> {
> my_xml = new XML();
> my_xml.onLoad = myOnLoad;
> my_xml.load("some.xml");
> }
>
> The myOnLoad function would run in the scope of XML, not in the
scope of the
> class. Various tricks were used to steer the scope back to the class.
> http://www.gskinner.com/blog/archives/000069.html
>
> Again, I am not suggesting to not use local variables; quite the
opposite to
> use them. I highly suggest you do not do what the above URL suggests.
>
> As for delete; don't know.
>
> ----- Original Message -----
> From: "thunderstumpgesatwork" <[EMAIL PROTECTED]>
> To: <[email protected]>
> Sent: Monday, February 20, 2006 1:50 PM
> Subject: [flexcoders] Re: Object cleanup and memory usage "Best
Practices"
> (2.0b1)
>
>
> Let me get this straight... did you suggest not to use local variables?
>
> "My suggestion; don't use it. And when you do (meaning you create
> local variables)"
>
> What do you suggest instead? I'm not making every variable a member
> variable...
>
> Thanks for the info on the Activation object. I will null out my local
> variables at the end of the function, but it sure seems weird to
> suggest not to use them at all!
>
> Also, seems like a pretty bad shortcoming not to have a deconstructor
> or finalizer or anything. One last question, does calling delete on an
> object release any Activation objects created for it?
>
> thanks,
> Thunder
>
> --- In [email protected], "JesterXL" <jesterxl@> wrote:
> >
> > Nope. Some people used onUnload for MovieClips, but I wouldn't
> touch that
> > method with a 10ft-pole.
> >
> > From the MM docs:
> >
> > "The Activation object. (A temporary object that is automatically
> created
> > when a function is called that holds the local variables called in the
> > function.)"
> >
> > The Activation Object can actually live on long after the function has
> > finished being removed from the stack. This is an ethereal plane
> that is
> > useful for getting around scope challengs people had in the early
> days of
> > ActionScript 2 development.
> >
> > My suggestion; don't use it. And when you do (meaning you create
local
> > variables), set them to null at the end of the function.
> >
> > function cow()
> > {
> > var a:String = "moo";
> > a = null;
> > }
> >
> > ----- Original Message -----
> > From: "thunderstumpgesatwork" <thunder.stumpges@>
> > To: <[email protected]>
> > Sent: Monday, February 20, 2006 12:56 PM
> > Subject: [flexcoders] Re: Object cleanup and memory usage "Best
> Practices"
> > (2.0b1)
> >
> >
> > Thanks for the tips. I a couple questions about your comments.
> >
> > - question regarding number 3,5... is there a deconstructor in
> > ActionScript that I can place cleanup code?
> >
> > - number 6 what do you mean by activation object? Do you mean
> > RemoteObject? if so, could you please explain how to clean it up
> > properly, as I need to use it, and there was no documentation on how
> > to clean it up.
> >
> > Thanks!
> >
> > --- In [email protected], "JesterXL" <jesterxl@> wrote:
> > >
> > > 6 rules of thumb:
> > >
> > > 1. never trust an alpha for benchmarking
> > >
> > > 2. never trust a beta for benchmarking
> > >
> > > 3. if it's a member variable, delete it:
> > >
> > > delete myVar;
> > >
> > > 4. if it's a local variable, null it at the end of the function:
> > >
> > > function cow()
> > > {
> > > var a:String = "";
> > > a += "one";
> > > a += "two";
> > > a = null;
> > > }
> > >
> > > 5. remove your event listeners before destroying the objects you
> > registered
> > > with
> > >
> > > 6. do not use the activation object unless you know how to clear it
> > later
> > > (most people I've seen in AS2 never do, so try not to use it
period).
> > > Example is xml.onLoad where the xml is created as a local variable
> in a
> > > function. It'll live on even though it's a local variable.
> > >
> > > ----- Original Message -----
> > > From: "thunderstumpgesatwork" <thunder.stumpges@>
> > > To: <[email protected]>
> > > Sent: Saturday, February 18, 2006 7:02 PM
> > > Subject: [flexcoders] Object cleanup and memory usage "Best
Practices"
> > > (2.0b1)
> > >
> > >
> > > Hi all,
> > >
> > > I've been coding in Flex now for a few months (basically since
the 2.0
> > > Alpha came out) and I've been having a heck of a problem with memory
> > > leaks.
> > >
> > > I was curious if there's any kind of rules or best practices to use
> > > for cleaning up AS objects (destructors? finalize()? or other?) This
> > > is especially pertinent because I am using lists/hash's, charts, and
> > > RPC Services.
> > >
> > > I couldn't really find any documentation regarding clean-up and
memory
> > > leaks. Does anyone out there have any experiences/knowledge to
share?
> > >
> > > Below, I'll outline my architecture, and note that I have no
> > > cleanup/de-construction code right now at all, other than setting
> > > variable references to new objects or null. Sorry it's pretty
long, so
> > > if you want to stop reading here and provide any ideas you have,
feel
> > > free =)
> > >
> > > thanks,
> > > Thunder
> > > _____________
> > >
> > >
> > > Basically I am running dynamic DB queries through a singleton
> > > RemoteObject called by a "ChartResults" class that holds the results
> > > (e4x XML) of the query and metadata info related to it. I have
> > > employed the "Asynchronous Completion Token" documented approach to
> > > allow the ChartResults classes to pick out only their calls from the
> > > singleton R.O.
> > > Is this detrimental to performance if there are anywhere from
4-10 SQL
> > > calls possibly going through the one RemoteObject? (note - that's an
> > > upper limit during initial startup only)
> > >
> > > The ChartResults class caches information as it is retrieved
from the
> > > results (often after performing filtering/sorting, etc).
> > >
> > > When a new query result comes in, the I clear all the cache
> > > items by setting the hash objects or Array to null or new
Object/Array
> > > respectively.
> > >
> > > 1 - Does setting a property referencing a Collection to null also
> > > release the source Array held in it?
> > >
> > > 2 - Do I also need to set each item in the Array to null?
> > >
> > > 3 - If a hash Object had many different XMLList properties cached,
> > > do I need to iterate and null all these properties using
> introspection?
> > >
> > > Also, on the Chart side, I have been deleting the series array and
> > > creating a new one when re-populating the chart (if it is showing
> > > entirely new/different data).
> > >
> > > 4 - Do I need to do any cleanup of the series items maybe?
> > >
> > > 5 - Are the Series getting cleaned up and releasing their
dataProvider
> > > objects?
> > >
> > > Somewhere I am leaking memory badly as the number of chart queries
> > > goes up and up...
> > >
> > > Thanks again!
> > > Thunder
> > >
> > >
> > >
> > >
> > >
> > >
> > > --
> > > Flexcoders Mailing List
> > > FAQ:
http://groups.yahoo.com/group/flexcoders/files/flexcodersFAQ.txt
> > > Search Archives:
> > http://www.mail-archive.com/flexcoders%40yahoogroups.com
> > > Yahoo! Groups Links
> > >
> >
> >
> >
> >
> >
> >
> > --
> > Flexcoders Mailing List
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> > Search Archives:
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> >
>
>
>
>
>
>
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