Flex: Variable accessible for all .mxml files

Im using Oracle, BlazeDS, Java & Flex. I have an ArrayCollection containing data from a small database table. This table won't be the subject of much change. I w开发者_JAVA百科ant to use this ArrayCollection accross different mxml files to fill e.g. ComboBoxes etc.

The reason for asking, is that doing a database call for each time a fill a ComboBox etc is slow and seems unnecessary. I tried doing this once in the "main" .mxml file, but then the variable wasn't accessible where i needed it.

What is the best approach for accomplishing this task? What is the best way of making a variable accesible across .mxml files? :)

[Bindable] public static var yourArrayCollection:ArrayCollection

That should make it visible anywhere but using static variables is normally not a good idea.

You could also implement a singleton instance to persist a variable if you do not want to make it static and need to reference other functions etc - but I think the static variable should do fine.

If this is a larger application, I'd recommend looking at Parsley: http://www.spicefactory.org/parsley/. With Parsley, you could add the array collection to the context and simply inject it whenever you need to reference it. The array collection should be populated during application startup and can be updated as needed.

There basically are two ways. The singleton way, and the static class way. A singleton is a class that is only instanciated once, through a mechanism described here, for instance. A static class is a bit different from a regular class : you will not instanciate it, first of all.

For more information about how implement a singleton in ActionScript 3 : here.

For more information about static classes and variables : here.

You can just make it public member of some class and import that class in all MXML-based classes:

public class DBWrapper {
    [Bindable]
    public var ItemList:ArrayCollection;
}

I usually make it a static member of a Globals class

public class Globals {
    [Bindable] public var iCollection:ArrayCollection;
}

It can be accessed from anywhere in the program (provided you have assigned a valid ArrayCollection to it first)

combobox.dataProvider=Globals.iCollection;