package
{
	import flash.desktop.NativeApplication;
	import flash.desktop.SystemIdleMode;
	import flash.display.Sprite;
	import flash.display.StageAlign;
	import flash.display.StageScaleMode;
	import flash.events.*;
	import flash.system.Capabilities;	
	
	[SWF(width="1024", height="600", backgroundColor="#f1f1f1", frameRate="24")]
	public class Main extends Sprite
	{
		private static const FRAME_RATE_DEFAULT:Number	= 24;
		private static const FRAME_RATE_STANDBY:Number	= 4

		public function Main()
		{
			stage.align = StageAlign.TOP_LEFT;
			stage.scaleMode = StageScaleMode.NO_SCALE;
			stage.addEventListener(Event.ACTIVATE, onActivateHandler, false, 0, true );
			stage.addEventListener(Event.DEACTIVATE, onDeactivateHandler, false, 0, true );
			addEventListener(Event.ADDED_TO_STAGE, init, false, 0, true );	

			NativeApplication.nativeApplication.addEventListener(Event.EXITING, onExitHandler, false, 0, true ); 
			
			checkEnvironment()
		}
		
		private function checkEnvironment():void
		{
			if (Capabilities.manufacturer.indexOf('VMware') == -1) {
			    //It is a BlackBerry PlayBook Tablet.
			} else {
			    //It is a BlackBerry PlayBook Simulator.
			}		
		}

		private function init( e:Event ):void
		{
			//Self Destruct Handler
			e.currentTarget.removeEventListener(e.type, arguments.callee );
		}

		private function onExitHandler( e:Event ):void
		{
			NativeApplication.nativeApplication.exit(0);
		}

		private function onActivateHandler( e:Event ):void
		{
			//trace( "Main::onActivateHandler:" );
			stage.frameRate = FRAME_RATE_DEFAULT;
			NativeApplication.nativeApplication.systemIdleMode = SystemIdleMode.KEEP_AWAKE;
		}

		private function onDeactivateHandler( e:Event ):void
		{
			stage.frameRate = FRAME_RATE_STANDBY;
			NativeApplication.nativeApplication.systemIdleMode = SystemIdleMode.NORMAL;
		}		
	}
}

package
{
	import flash.desktop.NativeApplication;
	import flash.desktop.SystemIdleMode;
	import flash.display.Sprite;
	import flash.display.StageAlign;
	import flash.display.StageScaleMode;
	
	import flash.events.*;
	
	[SWF(width="1024", height="600", backgroundColor="#f1f1f1", frameRate="24")]
	public class Main extends Sprite
	{
		private static const FRAME_RATE_DEFAULT:Number	= 24;
		private static const FRAME_RATE_STANDBY:Number	= 4

		public function Main()
		{
			stage.align = StageAlign.TOP_LEFT;
			stage.scaleMode = StageScaleMode.NO_SCALE;
			stage.addEventListener(Event.ACTIVATE, onActivateHandler, false, 0, true );
			stage.addEventListener(Event.DEACTIVATE, onDeactivateHandler, false, 0, true );
			addEventListener(Event.ADDED_TO_STAGE, init, false, 0, true );	

			NativeApplication.nativeApplication.addEventListener(Event.EXITING, onExitHandler, false, 0, true ); 
			NativeApplication.nativeApplication.systemIdleMode = SystemIdleMode.KEEP_AWAKE;
		}

		private function init( e:Event ):void
		{
			//Self Destruct Handler
			e.currentTarget.removeEventListener(e.type, arguments.callee );
		}

		private function onExitHandler( e:Event ):void
		{
			NativeApplication.nativeApplication.exit(0);
		}

		private function onActivateHandler( e:Event ):void
		{
			//trace( "Main::onActivateHandler:" );
			stage.frameRate = FRAME_RATE_DEFAULT;
		}

		private function onDeactivateHandler( e:Event ):void
		{
			stage.frameRate = FRAME_RATE_STANDBY;
		}		
	}
}

package
{
	import flash.desktop.NativeApplication;
	import flash.desktop.SystemIdleMode;
	import flash.display.Sprite;
	import flash.display.StageAlign;
	import flash.display.StageScaleMode;
	
	import flash.events.*;
	
	[SWF(width="1024", height="600", backgroundColor="#f1f1f1", frameRate="24")]
	public class Main extends Sprite
	{
		private static const FRAME_RATE_DEFAULT:Number	= 24;
		private static const FRAME_RATE_STANDBY:Number	= 4

		public function Main()
		{
			stage.align = StageAlign.TOP_LEFT;
			stage.scaleMode = StageScaleMode.NO_SCALE;
			stage.addEventListener(Event.ACTIVATE, onActivateHandler, false, 0, true );
			stage.addEventListener(Event.DEACTIVATE, onDeactivateHandler, false, 0, true );

			NativeApplication.nativeApplication.addEventListener(Event.EXITING, onExitHandler, false, 0, true ); 
			NativeApplication.nativeApplication.systemIdleMode = SystemIdleMode.KEEP_AWAKE;
		}

		private function onExitHandler( e:Event ):void
		{
			NativeApplication.nativeApplication.exit(0);
		}

		private function onActivateHandler( e:Event ):void
		{
			//trace( "Main::onActivateHandler:" );
			stage.frameRate = FRAME_RATE_DEFAULT;
		}

		private function onDeactivateHandler( e:Event ):void
		{
			stage.frameRate = FRAME_RATE_STANDBY;
		}		
	}
}

It seems that every time I work on a Blackberry app, by default I use some boilerplate code like this.  The idea is simply to handle the background events whenever a user flips to another application.

AS3: Blackberry Playbook Boilerplate

ActionScript 3