Big thanks Tracy ;-)
I religiously study your notes.
That I still need to master are relations between
MXML entities and AS ones (MXMLcode from/to AS
classes, MXML codes from/to AS scripts, MXML
components from/to AS classes and so on...)
By the way, you"re right, events are much cleaner
but I just wanted to gain time for a presentation draft :(
Thx !
Eric
At 2007-11-13 15:06, you wrote:
Ah, that is the problem. Packages and
namespaces are really compile-time things. You
dont use them in run-time references. Instead,
you want to use the run-time DOM.
There are several ways to reach up the
dom. One is application.application. You use
the id of your instantiated component to
reference its public members. So one way to do what you want is::
Import mx.core.Application;
private var _app:Application
_app = Application.application;
user = _app.loginpanel1.user
below are some additional notes on traversing the DOM.
Tracy
Communicating between Components:
Note: for "loose coupling" use events. But that is another topic.
A non-trivial flex application is "component"
based. While all of the built in controls are
components, the question of communicating
between components really only arises when you
are using a custom component. A custom
component, whether implemented in mxml or
ActionScript, has its own "scope". Within that
component (Application is a component too!), all
sibling child controls share the same scope, so
you can refer to controls by their id. If the
controls(components) have public properties or
methods, you can refernce those members directly through the id:
<mx:TextInput id="textinput1" text="test value" .../>
<mx:Text id="text1" ... text="{textinput1.text}" .../>
Ok, so far, its a "duh" right?
When you use custom components in a Flex app, at
run time they make a document object model
hierarchy (DOM). Each subcomponent has its own
scope and can't *directly* reference the member
properties or methods of its sibling subcomponents.
So again, within a component, you can refernce
siblings directly, as in the example above. But
there are two other cases inherent in a
hierarchy. You might want to reference "up", to
get to public members of the parent, or 'down",
to get to public members of some child.
Accessing members in the parent:
On an ordinary component DOM, you can reference
the parent component using the .parent
property. Say that a control with
id="textinput1" exists in the parent of the
current component. then you could do:
<mx:Text id="text1" ... text="{parent.textinput1.text}" .../>
Accessing members in the main application:
Components can be nested, sometimes very
deeply. If the reference you want is all the
way at the top-level, main application (the one
with the <mx:Application> tag), you could do
{parent.parent.parent.textinput1.text}, but you
would have to count the component levels just
right. Instead, you can use Application.application to get to that scope:
<mx:Text id="text1" ...
text="{Application.application.textinput1.text}" .../>
You can shoretn this style of reference by
importing mx.core.Application, and assigning
Application.application to a variable, like
_app, the doing (_app.textinput1.text)
Accessing members of a child component:
Say that in this case, a child component has the
TextInput control you want to reference. First,
make sure the child component has an id:
<myComp:MyCustomComp id="mycc1" .../>
Then, in the same scope (the same component/file
that contains as the tag above) you can say:
<mx:Text id="text1" ... text="{mycc1.textinput1.text}" .../>
Accessing a nested component:
As mentioned above you can go "up" the hierarchy
using "parent.parent...". You can als go "down"
the hirearchy using id references:
<mx:Text id="text1" ...
text="{mycc1.mycc11.mycc.12.textinput1.text}" .../>
Additional notes:
If you are using SWFLoader to load an entire
Application, you can reference the immediate
parent application using "parentDocument". You
can also use Application.application to reach the main app, as shown above.
Accessing members of an application loaded by
SWFLoader is a bit more complicated. See the example here:
http://www.cflex.net/showFileDetails.cfm?ObjectID=690
----------
From: flexcoders@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of elr
Sent: Monday, November 12, 2007 11:47 PM
To: flexcoders@yahoogroups.com
Subject: RE: [flexcoders] reference a class instance from another mxml
Yes Tracy both of my 2 mxml (A and B) are in
a directory /comps and both have this:
xmlns:comps="comps.*"
namespace reference. Maybe I missed something
but it sounds correct as Flex code hinting lists
me all my components as soon as I type down 'comps'.
LoginPanel was instanciated in a state of Main.mxml (the Application)
Here's Main.mxml:
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml";
xmlns:user="classes.*"
xmlns:comps="comps.*" >
<mx:states>
<mx:State name="connected">
<mx:RemoveChild target="{loginpanel1}"/>
<mx:AddChild position="lastChild">
<comps:UserPanel >
</comps:UserPanel>
</mx:AddChild>
</mx:State>
</mx:states>
<comps:LoginPanel id="loginpanel1">
</comps:LoginPanel>
</mx:Application>
Here's what my mxml B (UserPanel) looks like (
User class is located in /classes dir)
<?xml version="1.0" encoding="utf-8"?>
<mx:Panel xmlns: mx="http://www.adobe.com/2006/mxml";
xmlns:user="classes.*"
xmlns:comps="comps.*"
creationComplete="init()">
<mx:Script>
<![CDATA[
import classes.*;
private var user:User;
private function init():void{
...
user=comps.LoginPanel.user //error 1119 at this line !!!
...
}
...
]]>
</mx:Script>
...
</mx:Panel>
Again ,thank's all for your help ;)
Eric
At 2007-11-12 20:18, you wrote:
Hmm, namespace in this context makes me
nervous. You want to access subcomponents via
their id, when that id is in scope. You do
not use namespaces, unless I am misunderstanding your use of the word.
Show us a bit of code. How are you instanitating LoginPanel?
Tracy
----------
From: flexcoders@yahoogroups.com [
mailto:[EMAIL PROTECTED] On Behalf Of elr
Sent: Monday, November 12, 2007 6:27 PM
To: flexcoders@yahoogroups.com
Subject: RE: [flexcoders] reference a class instance from another mxml
No Gordon. unfortunately my instance was
public. I even defined a getter but no way:I
still get an 1119 error in my second mxml (B) at line:
user=comps.LoginPanel.user;
where of course comps is the namespace targeting my LoginPanel.mxml
Eric
At 2007-11-12 17:05, you wrote:
When your login component created a User
instance, did it store it in a public instance
variable (say, 'user') of the login component?
If so, it should be accessible as myLoginComponent.user.
- Gordon
----------
From: flexcoders@yahoogroups.com [
mailto:[EMAIL PROTECTED] On Behalf Of elr
Sent: Sunday, November 11, 2007 5:03 PM
To: flexcoders@yahoogroups.com
Subject: [flexcoders] reference a class instance from another mxml
HI,
I can't find a way to access from an mxml B to a class C that was
instanciated in a mxml A
In my sample. a login component (mxml A) instanciates a user:User
As soon as login is done, the second component (mxml B) should
retrieve the user instance
I referenced this user instance starting from component that composes
it (mxml A) but I always get a 1119 error:Access of possibly
undefined property user through a reference with static Class...
Thx for your help
Eric
