[Flashcoders] Synchronous code?
Hi,
More of a strange encounter that I would like to share / get some
input on than something I need to fix this one...
I have recently encountered an issue where I am getting null for the
stage property of a Sprite subclass in it's event handler for
ADDED_TO_STAGE. I have managed to work-around the problem, but have not
addressed the core issue I think.
My app has states for operation and uses an XML socket to communicate.
States are: NORMAL, ADMIN and ERROR. ERROR means the XML socket has
disconnected, the other two states just have different levels of access
control. Each state has a corresponding AppScreen subclass, some
containing lots of the above Sprites.
I can go into my ADMIN state from the ERROR state, but when the
Admin screen was added to the stage it tried to send something via the
XML socket class which sent an Error event to the App and resulted in
the application switchin back to the ERROR state. The Admin screen
contained lots of the Sprite subclasses with the ADDED_TO_STAGE handler,
but it seems that stage property of the Sprite subclass was actually
null'd between the calling of the event and the accessing of the stage
property and I end up with an exception in my Sprite subclass, e.g.
protected function _addedToStageHandler(e:Event):void {
//This would throw an exception because the stage is null at
this point?
///... some setup code, then:
stage.addEventListener(MouseEvent.MOUSE_UP,
_stageMouseUpHandler, false, 0, true);
}
So any ideas why this would happen? Is it because I am calling send on
the socket which is an OS level thing and outside the normal Flash
Player thread of execution, or am I fantasizing here? I have worked
around the problem which does flag an error when commands are sent to
the disconnected socket (I still catch the exception, but listen for the
error in a different place).
Thanks for any insights.
Glen
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Re: [Flashcoders] Synchronous code?
Hi, Glen,
Sounds pretty wacky to me.
I'm going to ask a dumb question just to be sure...
In the code snippet, the event handler is inside the Sprite subclass itself?
In other words, I wanted to make sure that your reference to stage is
indeed the property of the event source, i.e. would this be functionally
equivalent:
Sprite(e.target).stage.addEventListener(MouseEvent.MOUSE_UP,
_stageMouseUpHandler, false, 0, true);
Just trying to cover all the bases.
-jonathan
On Tue, Mar 9, 2010 at 6:39 AM, Glen Pike g...@engineeredarts.co.uk wrote:
Hi,
More of a strange encounter that I would like to share / get some input on
than something I need to fix this one...
I have recently encountered an issue where I am getting null for the
stage property of a Sprite subclass in it's event handler for
ADDED_TO_STAGE. I have managed to work-around the problem, but have not
addressed the core issue I think.
My app has states for operation and uses an XML socket to communicate.
States are: NORMAL, ADMIN and ERROR. ERROR means the XML socket has
disconnected, the other two states just have different levels of access
control. Each state has a corresponding AppScreen subclass, some containing
lots of the above Sprites.
I can go into my ADMIN state from the ERROR state, but when the Admin
screen was added to the stage it tried to send something via the XML socket
class which sent an Error event to the App and resulted in the application
switchin back to the ERROR state. The Admin screen contained lots of the
Sprite subclasses with the ADDED_TO_STAGE handler, but it seems that stage
property of the Sprite subclass was actually null'd between the calling of
the event and the accessing of the stage property and I end up with an
exception in my Sprite subclass, e.g.
protected function _addedToStageHandler(e:Event):void {
//This would throw an exception because the stage is null at this
point?
///... some setup code, then:
stage.addEventListener(MouseEvent.MOUSE_UP, _stageMouseUpHandler,
false, 0, true);
}
So any ideas why this would happen? Is it because I am calling send on
the socket which is an OS level thing and outside the normal Flash Player
thread of execution, or am I fantasizing here? I have worked around the
problem which does flag an error when commands are sent to the disconnected
socket (I still catch the exception, but listen for the error in a different
place).
Thanks for any insights.
Glen
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--
-jonathan howe
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Re: [Flashcoders] Synchronous code?
Hi,
The added to stage handler is inside the Sprite subclass:
public function GenericButton(attrs:* = null){
this.attrs = attrs;
addEventListener(Event.ADDED_TO_STAGE, _addedToStageHandler,
false, 0, true);
addEventListener(Event.REMOVED_FROM_STAGE,
_removedFromStageHandler, false, 0, true);
}
jonathan howe wrote:
Hi, Glen,
Sounds pretty wacky to me.
I'm going to ask a dumb question just to be sure...
In the code snippet, the event handler is inside the Sprite subclass itself?
In other words, I wanted to make sure that your reference to stage is
indeed the property of the event source, i.e. would this be functionally
equivalent:
Sprite(e.target).stage.addEventListener(MouseEvent.MOUSE_UP,
_stageMouseUpHandler, false, 0, true);
Just trying to cover all the bases.
-jonathan
On Tue, Mar 9, 2010 at 6:39 AM, Glen Pike g...@engineeredarts.co.uk wrote:
Hi,
More of a strange encounter that I would like to share / get some input on
than something I need to fix this one...
I have recently encountered an issue where I am getting null for the
stage property of a Sprite subclass in it's event handler for
ADDED_TO_STAGE. I have managed to work-around the problem, but have not
addressed the core issue I think.
My app has states for operation and uses an XML socket to communicate.
States are: NORMAL, ADMIN and ERROR. ERROR means the XML socket has
disconnected, the other two states just have different levels of access
control. Each state has a corresponding AppScreen subclass, some containing
lots of the above Sprites.
I can go into my ADMIN state from the ERROR state, but when the Admin
screen was added to the stage it tried to send something via the XML socket
class which sent an Error event to the App and resulted in the application
switchin back to the ERROR state. The Admin screen contained lots of the
Sprite subclasses with the ADDED_TO_STAGE handler, but it seems that stage
property of the Sprite subclass was actually null'd between the calling of
the event and the accessing of the stage property and I end up with an
exception in my Sprite subclass, e.g.
protected function _addedToStageHandler(e:Event):void {
//This would throw an exception because the stage is null at this
point?
///... some setup code, then:
stage.addEventListener(MouseEvent.MOUSE_UP, _stageMouseUpHandler,
false, 0, true);
}
So any ideas why this would happen? Is it because I am calling send on
the socket which is an OS level thing and outside the normal Flash Player
thread of execution, or am I fantasizing here? I have worked around the
problem which does flag an error when commands are sent to the disconnected
socket (I still catch the exception, but listen for the error in a different
place).
Thanks for any insights.
Glen
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