Making buttons link - Adobe flex - Blackberry Playbook

Question

Maybe a simple question but I'm having alot of trouble making a button change the view of a Flex blackberry playbook app. I am coding it entirely in actionscript, no MXML.

myButton.addEventListener(MouseEvent.CLICK, doSomethingOnClick);

private function doSomethingOnClick(e:MouseEvent):void {
    navigator.pushView(view.Login, "testdata");
}

When I try this I get:

1120: Access of undefined property navigator.

Which is weird as it works in a MXML file. How do I change views in actionscript?

Thanks Phil

EDIT: Cheer J_A_X, but now i have:

navigator = new ViewNavigator();
navigator.pushView(net.airpoint.assessments.view.Login, " ");

TypeError: Error #1009: Cannot access a property or method of a null object reference.

Apologies, as I realise this is really simple stuff but it just isnt clicking!

Update 2 *Assessments.as*

package
{
    import flash.display.Sprite;
    import flash.events.Event;

    import net.airpoint.assessments.view.*;

    import qnx.ui.core.Container;
    import qnx.ui.core.ContainerAlign;
    import qnx.ui.core.ContainerFlow;
    import qnx.ui.core.Containment;
    import qnx.ui.text.Label;

    import spark.components.ViewNavigator;

    [SWF(height="600", width="1024", frameRate="30", backgroundColor="#FFFFFF")]

    /* Main Layout */

    public class Assessments extends Sprite
    {
        //containers 
        private var main:Container;
        private var menu:Container
        private var firstLabel:Label;
        private var navigator:ViewNavigator;


        public function Assessments()
        {
            initializeUI();
        }

        private function initializeUI():void
        {
            main = new Container();
            main.padding = Vector.<Number>([20,20,20,20]);
            main.flow = ContainerFlow.HORIZONTAL;
            main.debugColor = 0xFFCC00;

            firstLabel = new Label();
            firstLabel.text = "First label";
            firstLabel.size=35;

            main.addChild(firstLabel);

            addChild(main);

            navigator = new ViewNavigator();
            navigator.pushView(Login, " ");

        }
    }
}

Login.as

package net.airpoint.assessments.view
{
    import flash.display.Sprite;
    import flash.events.MouseEvent;

    import qnx.ui.buttons.Button;
    import qnx.ui.core.Container;
    import qnx.ui.text.Label;
    import qnx.ui.text.TextInput;

    import spark.components.View;

    public class Login extends View
    {

        private var usernameLabel:Label;
        public function Login()
        {
            initializeUI();
        }

        public function initializeUI():void
        {
            usernameLabel.text = "test";

            this.addChild(usernameLabel);
        }               
    }
}

Answer 1

Something isn't right. If it's a Flex Mobile Project, you need an Application at the top level (you know, like how Flash Builder created the project with an mxml file). Either you create an actionscript file that extends Application as mentioned here or you just use an mxml file for the root component.

However, your argument to 'not use mxml' is redundant if you're using Flex components. If you're using Flex components, you're using mxml no matter what, so there's no performance increase. If anything, RIM is recommending to use AS only because their SDK is AS only (which is idiotic anyways). You could always add their UI component through AS in mxml files.

So really, the point is moot and you should just use mxml anyways since it's better than straight AS for UI layout and skinning. Either that or go Pure AS with no Flex components.