The Space For App Developers

Hooray! My Adobe LCDS Samples application was successfully reviewed and accepted in BlackBerry App World! If you have your PlayBook you can install it directly from here.

My experience of publishing to the App World was really straightforward although it took about 8 working days to have my app reviewed and accepted. In advance of that I had to register as a RIM vendor, which took an additional two working days (the good thing is that this registration is free of charge at least for now).

So if you are planning to publish anything to App World be prepared for at least 10 working days for the whole process. I guess this can be a bit annoying for developers, especially those who are used to Android Market instant publishing. I guess with App World the process is more human-centric, so hopefully the end customers receive only high quality and secure apps. With Android Market that may not always be true.

Recently I was looking for an example on how to create a skin that would work with the SkinnableContainer component class in a Flex mobile application. It turned out I couldn’t find any examples available in the wild so I had to dig it out myself. So below is the approach I took, which can also work for others.

The first thing I found out is that there is a SkinnableContainerSkin class in the spark.skins.mobile package that extends MobileSkin class. This is a basic implementation that works out-of-the-box when you use SkinnableContainer in mobile projects. Its only behavior is setting a contentGroup property with a new instance of the Group class and drawing a background rectangle filled with color based on the backgroundColor style.

Now my goal, instead of drawing the background with AS3, was to use a custom FXG file with some rounded corners, simple stroke and gradient. The screenshot below demonstrates what I was looking for:

In order to achieve the example above I extended SkinnableContainerSkin as in the following snippet:

package
{
	import spark.core.SpriteVisualElement;
	import spark.skins.mobile.SkinnableContainerSkin;
 
	public class MySkinnableContainerSkin extends SkinnableContainerSkin
	{
		protected var backgroundClass:Class;
 
		protected var background:SpriteVisualElement;
 
		public function MySkinnableContainerSkin()
		{
			super();
 
			// Here could be a DPI dependent logic, for demo purposes it is not necessary
			backgroundClass = MySkinnableContainerBackground;
		}
 
		override protected function createChildren():void
		{
			// Adding container background
			background = new backgroundClass;
			addChild(background);
 
			// Creating content group instance
			super.createChildren();
		}
 
		override protected function layoutContents(unscaledWidth:Number, unscaledHeight:Number):void
		{
			super.layoutContents(unscaledWidth, unscaledHeight);
 
			// Setting size of background container
			setElementSize(background, unscaledWidth, unscaledHeight);
		}
 
		override protected function drawBackground(unscaledWidth:Number, unscaledHeight:Number):void
		{
			// By default SkinnableContainerSkin draws Rect with backgroundColor but this is not
			// required in this case since background is constructed of MySkinnableContainerBackground fxg
		}
	}
}

My FXG file content looked like this:

<?xml version='1.0' encoding='UTF-8'?>
<Graphic xmlns:fc="http://ns.adobe.com/flashcatalyst/2009" xmlns:d="http://ns.adobe.com/fxg/2008/dt" 
		 xmlns="http://ns.adobe.com/fxg/2008" version="2.0"
		 scaleGridLeft="10" scaleGridTop="10" scaleGridRight="90" scaleGridBottom="90">
 
	<Rect radiusX="10" width="100" height="100">
		<fill>
			<LinearGradient rotation="90">
				<GradientEntry alpha="1.0" color="#CCCCCC" ratio="0"/>
				<GradientEntry alpha="1.0" color="#666666" ratio="1"/>
			</LinearGradient>
		</fill>
		<stroke>
			<SolidColorStroke color="#FF0000" weight="2"/>
		</stroke>
	</Rect>
 
</Graphic>

And the way I can use it now in my Flex mobile projects is as follows:

<s:SkinnableContainer left="10" top="10" right="10" bottom="10" skinClass="MySkinnableContainerSkin">
	<s:Label left="10" top="10" right="10" bottom="10">
		<s:text>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam eget arcu et nibh vehicula pulvinar sit amet sit amet ligula. Duis a orci at nisi faucibus luctus. Quisque congue vulputate porttitor. Curabitur ac turpis nulla, a malesuada diam. Sed ullamcorper massa ac libero tincidunt vel ultrices odio cursus. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Fusce pharetra varius tortor id rutrum. Duis tempor, nisl sit amet scelerisque dignissim, lorem nisl vehicula leo, in auctor dolor turpis at nisl. Quisque bibendum faucibus turpis vitae pulvinar. Sed mollis risus eget turpis molestie laoreet. Aenean metus nulla, vestibulum at egestas quis, aliquet tempus lectus.</s:text>
	</s:Label>
</s:SkinnableContainer>

During this year’s MAX I will be doing a presentation about things that are very useful but for some reason little known and rarely used in everyday Flex and AS3 development. The name of my session is “Discover the Unknown Flex 4.5”. This session is for you if you wants to learn new Flex/AS3 tips & tricks, check if you really know everything about Flex, and/or share your knowledge with others.

One of my goals is also to let anyone share their own tips & tricks so I’m expecting to initiate a free form discussion during the session. If you will not be attending this year’s MAX, I encourage to send me your input in advance. I will include most interesting proposals in my presentation, of course giving attribution to their authors

You can use this contact form or use comments below to send me your input.

So see you at MAX 2011…

Very recently I was looking for a simple and affordable solution to host Java-based services for the mobile version of my LCDS Samples application. Unfortunately, with the Java development, life is not as easy as with PHP where you can get affordable hosting that is managed and secured by your hosting provider. The reality is that with Java you usually end up having a VPS or an instance of a dedicated Linux server (of course Windows would work also). This is certainly a very good solution that gives you a lot of flexibility but you have to remember that the tasks of administering and securing your box are usually on your shoulders. Although I have some knowledge of Unix-type systems, to be honest I wouldn’t feel comfortable doing the whole administration on my own.

So after some research and trying out different options I ended up with an AWS Elastic Beanstalk service provided by Amazon (you can see it in action running here). I’m really excited about this service because it provides an instance of Tomcat (both 6.x and 7.x versions are available) hosted and managed on Amazon’s cloud infrastructure. On top of that and out-of-the-box, it provides a load balancer that will automatically launch additional instances if your application encounters the increased load. Also you have full access to your Tomcat logs and you can receive email notifications with the status and health of your running services.  Another important thing is that it is extremely easy to use, especially when you install the AWS Eclipse plugin that can also work well with Eclipse/Flash Builder.

The good thing is that the cost of all this is not really high, the entry level service is just about $35.27 a month, more details about pricing are available here.

Getting started

Follow these steps to get up and running:

1. Get an account (if  you don’t already have one) with AWS (Amazon Web Services). Once you get an account you can sign up for Elastic Beanstalk via the “Manage Your Account” section.
2. Configure your IDE environment. By default Flash Builder comes with a standard version of Eclipse that has only the JDT available. I suggest downloading the Eclipse IDE for Java EE Developers and to configure FB with this environment. It will give you additional tools to handle Tomcat instances and Java Web Projects, which you can use when developing for Elastic Beanstalk. Configuring FB with a custom installation of Eclipse is really straightforward. Once you download Eclipse from here and you extract it somewhere to your hard drive, you can go to the folder where you have FB installed and find the Adobe Flash Builder 4.5 Plug-in Utility application located in the utilities folder. In my case it is here “/Applications/Adobe Flash Builder 4.5/utilities/Adobe Flash Builder 4.5 Plug-in Utility.app” but it all depends where you have your FB installation and also on what OS you are on. Run this application and it will guide you with a few simple steps through the whole Flash Builder – Eclipse integration process.
3. Install the AWS Eclipse plugin. This can be done directly from Eclipse. Just go to the Help -> Install New Software menu and enter the following update site URL: http://aws.amazon.com/eclipse
   
4. Create a new AWS Java Web Project. After a successful install of the AWS plugin you will have an option to create new AWS projects. Use the wizard available from the top bar of Eclipse (with an AWS icon on it) to create a New AWS Java Web Project. First you will need to enter a project name, and credentials like Access Key ID and Secret Access Key. These values are generated when you sign up for an AWS account and you can copy them from the Security Credentials section of your AWS account.
   You can select the Basic Java Web Application option (see the screenshot above), this will be enough for the LCDS/BlazeDS scenario. More info about other options is available through this site, with an in-depth video tutorial.
5. Configure the LCDS/BlazeDS  environment. In order to do that you need to, copy all necessary jars into the WebContent/WEB-INF/lib folder of the newly created project. In my case I used a turnkey installation of LCDS and I just copied jars from the lcds-samples application and also jars from tomcat/lib/activemq4.1.1, tomcat/lib/jotm2.0.10 and tomcat/lib/lcds (this wouldn’t be necessary for BlazeDS but for LCDS it was required to make the DataServices and Messaging work properly). Next you will also need to copy all configuration files from the WEB-INF/flex folder and the web.xml that has all necessary LCDS/BlazeDS servlets/listeners configured. The important thing to note here is that by default the AWS Elastic Beanstalk service enables only port 80 and HTTP channels; in order to enable other ports that could be required for RTMP channels you can modify the AWS EC2 Security group settings (but that is a topic for another blog post and I will not cover it here). Another solution you have is to stick to the default settings and to configure LCDS services to use only HTTP channels; this is actually what I did for my lcds.riaspace.comservice.    One last thing I had to do to make the LCDS function properly was to create a WebContent/META-INF/context.xml file in which I defined the transaction configuration as in the following snippet:

   <?xml version="1.0" encoding="UTF-8"?>
   <Context reloadable="true">
     <Transaction factory="org.objectweb.jotm.UserTransactionFactory" jotm.timeout="60"/>
   </Context>

6. Deploy your application to the cloud. Once you have the configuration completed and all the services built you can deploy your application directly from Eclipse. Just right-click on the project and select the Amazon Web Services -> Deploy to AWS Elastic Beanstalk… option. Another wizard will pop up that will ask you to specify names for your application and environment.Next you will need to select the server type, which would be AWS Elastic Beanstalk for Tomcat 6 (you also have the option to deploy to Tomcat 7 instances).
   At last you will be able to specify the CNAME of your server (you can assign your own domain name in the DNS configuration, that is actually what I used to get the default lcds-samples.elasticbeanstalk.com configured as lcds.riaspace.com). Another valuable option here is to enter your email address, which will receive notifications of any changes to the service’s state and health.

   

   Now you are ready to click the Finish button and it will start uploading and configuring your application in the cloud. Be aware that this process may take several minutes the first time. Once it is done you will be able to access your services via the following URL: http://yourcname.elasticbeanstalk.com. To redeploy any changes made to your services you just need to follow this last step all over again.