Tricks for tween on mobile devices with Flash Platform

In this quick post I’d like to share with you my experience about Tween on Flash Platform projects delivered on a mobile devices.
I started work on mobile since Flash Lite 1.1 so I grew up with mobile, I lived all the Flash mobile evolution and now, on tablet and smartphone, I had some good tricks to share with you, I really hope that those tips could help you during your developer life.
OK, let’s start:

  • Use quality property of stage
    This is a really good technique to use when you have to improve performance of your project, when you need to make a fluid tween before launch it, set stage quality to low and when tween will finish set stage quality to high or best.
    Avoid to use this technique when you have vectors (textfield for example) on the stage because you could have a worst result.
  • Use cacheAsBitmap and cacheAsBitmapMatrix
    If you have vector object that you’d like to animate in your project remember to cache them and then animate; remember also to set your application with GPU acceleration and you can see a really good performance with this technique.
    Avoid to cache objects that you need to remove from display list, it will be so expensive for your memory.
  • System.gc() works!
    I tried in few sample to use it on Android and I saw a good result, so the “old” tip to call System.gc() twice in a try/catch statement works on mobile device too (only on AIR apps)
  • Take care with multiple animations on iPad and iPhone
    On iOS devices we don’t have AIR runtime so LLVM translate our AIR project for us in Native Binary so it could help if you move few objects per time in particular if you have big objects to move like a background or something like that
  • Greensocks tweens are the best
    I tried tweener and other tween libraries for AS3, but the best one for me are the Greensock tween library, in particular on iOS devices.
  • Last but not least, remember to test your animation on the device because you could see “funny” results
    Sometimes happen that on your computer everything works well but when you port your content on a tablet or smartphone everything works not so well.
    Before hurt your head, remember to test a lots of times your mobile content on the device, it could save your projects!
Finally I suggest to take a look at dev center mobile development zone of Adobe site because you can find many tutorials and helpful tips on mobile development.
That’s all folks for now, I hope you enjoy those tips.

Presentation Model design pattern: multiple screen solution – part 1

Today I’d like to talk about Presentation Model design pattern because it’ll be so useful for anyone that is working on multiple screen project with Flash or Flex.
In latest months we lived in phrenetic mobile world where we have tons of new and powerful devices on the market with different screen sizes, different hardware and so on, on the other hand we have clients that are looking for new business opportunities and they are seeking a way to spend less but earn more.
So, one way to solve those problems could be find a way to deploy with the same technology in different devices (tablets, smartphones, computers…) saving time with great results!
That’s not a dream, it could be made with knowledge, architecture and a good developer or a team!

Our goal

For a developer find a way to have a good project architecture to maintain it’s so important, usually when you start a project you try to define the parts that could be re-usable in different part of the same project or in different project too.
So our aim is find a way to write less code but it will cover the project needs and that could be portable in different screens / operating systems easily.

What is Presentation Model design pattern?

My mentor Martin Fowler describes it with those words: “Represent the state and behavior of the presentation independently of the GUI controls used in the interface”  (here the full article of Martin Fowler).
In fact with this pattern we divide UI (components, movieclips, sprites…) from their behaviors; each view will have one and only that one presentation model and only the presentation model will interact with the whole architecture (like with model or proxy…).
Probably with this image you can easily understand better this concept (from Martin Fowler website):

Like you can see we have 3 class, AlbumTitle that is a view with a textfield, AlbumPresentationModel that is the presentation model of AlbumTitle and it has the copy of the view but storing datas inside and finally the main model Album where we have the data that could be used for the whole application.
There aren’t any connection trough the views and the application model because only the presentation model has access to the whole project, so the view is only a bunch of components and custom graphics, this it means that if you have to change UI on a mobile project for a different device, changing the views and anything else, you will have done your job.
In fact with this easy technique you perfectly solve our problem and you should create the same content for different devices changing only the views.
Probably your application in different devices will have the same functionalities but with a different UI dedicated for the OS is running on.
With this sample design pattern you’ll have a solid infrastructure that will solve the big problem to port the same application in different screen sizes.
So in next paragraph we can take a look on how to organize our files project.

Manage a project for different screen sizes

Another important thing before starts the project is understand how to organize the project for different OS, in fact if you work with Adobe AIR on Android you’ll have only the XML descriptor with Android permissions described in this file, on Playbook you’ll have another XML file dedicated to this platform and so on.
So, my suggestion is to organize the project in different projects that work together.
In this image you can see how I organize it for our final scope, I’ve a common project (Runtime Shared Libraries in this case but you can use also an Actionscript or AIR project if you work with Flash for example) where I’ll put all classes that are common for different target, so in my case all the presentation models, main models, utils classes, my notification bus and views that are common for different projects like components for example.

In the target device projects I add only what I need for that device, in this case only a couple of views and assets but in big projects could be more stuff that those one:

When you have a specific behavior only for a target device, you can easily extends the common presentation model and add new functionalities or create a side class that you’ll add in the specific view.
So with this infrastructure you can solve bugs and change stuff directly on the common project and all the platforms will be ready to package the project and upload to their store. That’s cool, isn’t it?

Summary

So in this post I hope to give you some ideas on how to solve the big problem to create a common base code that could be useful for different purpose.
In next post I’ll show you how to implement it in practice, for now if you have any feedback or suggestions for the second part of this article please add a comment to this post.

New AT&T Research Reveals Clues to Smarter App Development

This time I’d like to publish a post written by Doug Sillars member of the AT&T Developer Program team, he asked me to publish it on my blog so here we are, great job Doug!

Nothing chases away users (or invites bad reviews!) like an app that is slow or drains battery life too quickly. New research from AT&T and University of Michigan offers insight into how applications can be modified to prevent these issues from occurring. Historically, wireless optimization best practices have focused on how to optimize content for smaller screens and slower processors. In this article, the researchers describe how mobile wireless networks are different than wired networks, and how simple changes to your app can work WITH the network to improve your application’s efficiency.

What is truly fascinating about this study is that developers are given a peek at network architecture and lower-level protocols that are usually hidden from them. The researchers describe in detail the connection latencies and state machines that exist in wireless networks, and how much longer these timeframes are than in traditional networks. The main takeaway for developers is that all connections open and close on the order of seconds (as compared to milliseconds in the wired web). These latencies make content downloads appear slow, and can drain the battery quickly.
The researchers point out that it is more efficient to utilize fewer connections to send more data per connection. For example: 5 connections of 1 KB each utilize 90 seconds of radio, while one 5 KB transfer uses 19 seconds (a 79% decrease in battery usage for the same amount of data!).

Each network connection causes a power drain to the battery, and can make your application appear slow to the end user. By sending more data per connection (and using fewer total connections), you can drastically improve your application’s performance. The researchers provide the example of a news application that downloads data on demand (e.g., images are downloaded when the user scrolls to them). They found that prefetching images (sending many files in anticipation of future use) can reduce power consumption by 15-18%. Since the images are downloaded in advance, they are available for display immediately, and your application appears faster. However, the researchers are quick to point out that prefetching data is a delicate balance, as downloading content that is never used also wastes the battery (and can cause your users to exceed their monthly data caps).

In the case of a popular music streaming service, periodic audience measurements were draining battery life, causing the app to use more than 40% of its power to transmit just 0.2% of its data. By lengthening the time between these measurements, it is possible to greatly reduce the battery drain, and allow users to listen to more music (and at the same time view more revenue-producing advertisements)!
AT&T has begun working with developers of popular applications (like Pandora and Facebook) to enthusiastic responses. The biggest response has been that the solutions to optimize wireless applications are straightforward and benefit both the developer and the end user!

Flash Camp Milan review

Yesterday in Milan we had the Flash Camp about Mobile topics and then we had the Flash Camp Party at NH Hotel… really wonderful time.
Like you know, in Italy it’s not so easy to organize those kind of events because usually people don’t move to another city like other foreign countries but Flash Camp had a great success.
This camp was organized in the same place of WhyMCA the mobile revolution, an italian conference focused on mobile topics.
We had 50/60 people per session and I’m glad to say that my session had 80 people so I’m happy about this little success.
All the sessions surfed in deep about CG, design patterns, video optimization for mobile, flex on mobile and so on, so I was really excited to take part in this event.
My session was about Design Pattern for Mobile, I talked about 3 design patterns: Singleton, Observer and Presentation Model.
With a couple of samples (that you can download from this link) and few slides I made an application that run with the same base code on tablet and smartphone; this is an hot topic now on mobile world in particular on Flash Platform side.


In next few weeks I’ll make a post about Presentation Model to share my thoughts about this argument and how to use it in your project , but if you want to start with this topic, take a look at this great post on RIArockstars.

Finally I’d like to thanks the Flash Mind, Adobe Flash Platform User Group Italy, to give me this opportunity, WhyMCA staff for the amazing organization, other speakers of Flash Camp for great time spent together and people that came to talk with us during the Flash Camp and to the beer party too.
I leave also a link to some photos took during Flash Camp in Milan.

Flash Camp in Milan

I’m glad to announce an interesting Flash Camp that will take place in Milan this month at 20 and 21.

All the topics of the Flash Camp will be focused on mobile side, so Flex for mobile device, iOS, Android and Playbook development, code technique for mobile applications, optimizing video content for mobile, design pattern and architecture for mobile project.
Flash camp will be hosted by the whymca the mobile developer conference, that for the second year will show the mobile opportunities not only with Flash Platform but with any technology could be use for mobile purpose.
The event will be in Milan in Milanofiori (Assago), you can find more information on whymca web site.

Back on the Flash Camp side, speakers will be:

Mihai will talk about Flex on mobile devices and how to deploy a content on multiple devices, in the afternoon he has a live coding session where show how to create a mobile application with Actionscript 3.
My good friend Fabio will talk about video encoding optimization for mobile devices, Andrea will show how to create a game cross-platform with Flash Platform and Piergiorgio will give us great suggestions on how to optimize our code and improve the performance of mobile solutions.
Finally me, I’ll talk on how to organize a multiple screen development with Design Pattern and Architecture to re-use code and have great performance on mobile solutions.
For a limit number of people we are organizing a post event for the evening so try to come from the beginning of the Flash Camp and you’ll receive more information about it or keep update reading this blog.
See you there Flashers!!!

Playbook development with Flash Platform

First of all a big THANKS to Mihai Corlan, Adobe Evangelist, that is helping me during this “journey”.
Everything start last year during MAX when I saw for the first time the new BlackBerry tablet: the Playbook 😀
It looked so nice, I thought that it was really amazing.
So after few months I decide to try… and now, I finally can announce that with Mihai we are working on a book on Playbook application development with Flash Platform!

It’ll be an hard job but I want to do it, I hope to receive useful suggestions and questions about this topic and believe me that I’ll be free to talk with you about that.
It will be a book made by developers for developers so I hope that you’ll enjoy it when will be released this september (more or less).
This book will cover following topics:

  • Build, port and optimize apps for the BlackBerry PlayBook tablet device
  • Work with the PlayBook OS APIs, ActionScript, Flex, AIR and other Flash tools/APIs for PlayBook
  • Build a simple app and consuming data
  • Create multimedia and gaming apps for the BlackBerry PlayBook
  • Debug and optimize your PlayBook app

For any news about this book and about Flash Platform development follow this blog and my twitter or facebook account.

Adobe CookBooks Reader for Android

Hi everyone,

I’ve just released on Android market the CookBooks Reader application where you can read all new recipes about Flash Platform technologies.
It’s FREE and it’s based on Flex 4 and Adobe AIR so remember to download it before download CookBooks Reader.

If you try it, feel free to leave here comments with new features or suggestions…  I’m looking for you! Let’s go Flash Platform geeks! 😛

Flex on mobile: first impressions…

Like you know I love work with mobile and embedded stuff, in particular I love working with Flash Platform on mobile devices.
In latest months I worked on Android and iOS with Flash Professional but in latest weeks I started to work with Flex HERO sdk.
I love so much work with Flex but on mobile I’ve never tried yet.
First impression is that work with Flex on mobile stuff is quite fast respect Flash because it adds a lots of usual features that a mobile application needs.

Splash page

Any mobile application that is called like that, needs a splash page to introduce the real application.
In Flex you can set it very easily directly in main MXML file.
The executable MXML file on mobile project is called ViewNavigatorApplication instead of WindowedApplication like every AIR application, this new class allow you to set splashScreenImage, splashScreenScaleMode and splashScreenMinimumDisplayTime.
Those properties allow you to choose an image file for the splash screen, set its minimum duration and finally how it works in each screen’s dimensions where application runs.

Views

I mention ViewNavigatorApplication, this is a new concept of Flex mobile applications, in fact each application is composed by different View components.
Views are so interesting because they have a lots of things pre-builted like ActionBar, activation and deactivation events, View title, caching data and so on.
Every view is managed by a navigator, with the navigator you can push or pop views (like an array) to change them.
You can also choose how they will be animated, by default you can see a simple slide left or right (depends if you are adding or removing a view).
ActionBar is a new interesting component composed by 3 elements:

  • navigationContent
  • titleContent
  • actionContent

Usually actionBar could be used like a context menu of the view, remember that on mobile development is necessary to go back in the previous mask and also remember that your user doesn’t work on an application like uses a desktop application so shortcuts are so important.

Mobile Components

The new Flex framework “Hero” added optimized components for mobile purpose.
Until now I worked with textinputs, labels and lists that works very well, I tried in 3 different Android phones and performance are quite good.
Another new component added is IconItemRenderer that is an optimized item renderer for list component for example.
This component could be customized with: title, message field, icon and a decorator class that allow you to add for example another image. This is an IconItemRenderer sample where I added also filters (a drop shadow in this case)

Device Interaction & Flex Performance

Another cool thing that allow you to save time is that back button on the smartphone is managed by the application and it automatically goes to the previous view when a user click on hit.
In my few samples I tried to work without using cacheAsBitmap and cacheAsBitmapMatrix to have better performance and believe me that you remain astonished by the performance.
In fact performance are so good, it is so optimized for mobile purpose and everything works well, I tried to add custom effects and filters but performance were amazing too.

Mobile project Architecture

This is my favorite topic, when I started to work on mobile stuff with Actionscript 3 I thought on how to have great performances but with a good architecture that allow me to maintain my application during own life.

So I investigated on how new mobile technologies work and I found that Nokia QT works on mobile with a MVVM architecture, usually instead of controllers you can use delegates but depends of the application.
Working with MVVM architecture and a good design pattern like observer you can solve any problem in a mobile project, performances are perfect and you can optimize your code in the best way you like.
There are other tests that I want to try, the first one will be using Signals instead of Observer, I’d like to know performances in a mobile project (stay tuned :P).

Final Conclusion

The new Flex framework is an interesting step to the future, with this framework I’m sure you can create cool application in few days focusing on details and not on the application skeleton.

I suggest to take a look at Adobe TV, Adobe labs and Adobe Opensource to start work with Flex HERO!

UPDATE

take a look here to the Flex mobile performance

Working with Adobe AIR FileSystem API on iPad

Recently I made some test on iPad to test how to update contents of my mobile applications.
I tried some new AIR 2 API like open default program with PDF or XLS files but I get error #3000 (privileges error).
My idea is to create a routine where I’ll be able to update all contents on my application without passing trough Apple store.
So I tried with URLStream and AIR filesystem API, everything works well.
Code is so easy, take a look here:

//RETRIEVING IMAGE FROM ANY WEBSERVER
var urlS:URLStream = new URLStream();
urlS.addEventListener(Event.COMPLETE, downloadComplete);
urlS.addEventListener(ProgressEvent.PROGRESS, showPerc);
urlS.load(new URLRequest("http://192.168.1.9:8888/oliviaWilde.jpg"))

//DOWNLOADED IMAGE BYTEARRAY AND LOADING IN LOADER
function downloadComplete(e:Event):void {

  perc_txt.text = "";
  fileData = new ByteArray();
  urlS.readBytes(fileData,0,urlS.bytesAvailable);
  bytes = urlS.bytesAvailable;
  l.loadBytes(fileData);
  l.addEventListener(MouseEvent.CLICK, saveIt);

}
//SAVE IMAGE INTO APPLICATIONSTORAGEDIRECTORY
function saveIt(e:MouseEvent):void{

  f = File.applicationStorageDirectory.resolvePath("a.jpg");
  var fs:FileStream = new FileStream();
  fs.open(f, FileMode.WRITE)
  fs.writeBytes(fileData);
  fs.close();

}

//LOAD IMAGE FROM APPLICATIONSTORAGEDIRECTORY 
function loadLocalImg(e:MouseEvent):void{

  var finalBA:ByteArray = new ByteArray();
  var fs:FileStream = new FileStream();
  fs.open(f, FileMode.READ);
  fs.readBytes(finalBA, 0, bytes);
  fs.close();
  l.loadBytes(finalBA);

}

Using applicationStorageDirectory, you can save data into your application and retrieve it with AIR API.
In the video below, you can see a little demo where I load an image from a server, I save it, I unload click on the black right button and finally I load again but from ApplicationStorageDirectory, with the black left one, instead of loading from webserver.

Review: HTML5 Mobile Web Development

A couple of weeks ago I became blogger reviewer for O’really, so I take this opportunity to open my mind and learn new stuff about new technologies, programmation languages, etc.

So this is my first review and I start with an HTML5 video course.
Why am I talking about HTML5 in this blog? Because I think it’s important to know and learn if it could be useful in some projects or not.

Starting with this idea I’ve decided to watch this video course about HTML5 on mobile development.
Video courses aren’t my favorite media to learn new stuff because I love to sign my books, add some notes…you know what I mean… but this time I was really impressed about how O’Reilly organized it.
Seems you are in a real classroom with teacher in front of you that show code examples, tips & tricks using HTML5, CSS3 on iPad or iPhone.
Course is focused on mobile development, Jake Carter, the author, shows also Android world, how to configure your computer to work with emulator and simulator for Android, iPhone and so on.

I really love the way that he works in the classroom because first of all he explains the powerful of a particular feature, then show how to implement it and finally a little part of Q&A from internet people (I suppose).
During this video course you can learn useful stuff, take a look at table of contents in O’reilly website.
It was my first time with HTML5 and I think is an interesting technology, in particular, during this course I learn how to work with geolocation,  with JS and Canvas, with audio and video API and again how to save data directly on the device in a database.
I appreciate a lot al meta and css dedicated to iPhone and iPad, very useful.
Finally if you are interesting to learn a new way to develop on mobile, I suggest to take a look at this reference.
It’s useful, easy and I think is a fast method to learn.