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I’ve been working on a project recently that involves a desktop AIR application running (mostly) offline with a local SQLite database. Occasionally the app will synch collected data remotely with a central server that will have an administrative and reporting web front end. Various parts of the AIR application involve filling out a series of multi-choice questions. Considering that the data will be used by two different systems, and anticipating that questions and answers may want to be updated from the admin portal, it seems a good choice to make things as dynamic as possible based on data from the db. It’s not a difficult problem to solve, and I’ve done it a time or two before, but since it’s fresh in my head and the code is in front of me, I’m going to use a couple blog posts to document the strategy.  The SQL presented is pseudo code and will not actually execute.

Part 1 is getting the database structure in place.

[SWF]http://www.pathf.com/sites/pfd/flash/player.swf, 520, 330, file=http://media1.www.pathfinder-development.com/assets/AirDat/3DFlex2.mov&image=http://www.pathf.com/sites/pfd/img/cases/3dflexview.png[/SWF]

As part of our ongoing development in the air traffic logistics and weather forecasting space, we developed a three-dimensional prototype for tracking flight path data and meteorological readings using Flex, Papervision 3D and PureMVC.

The framework is configured for using multiple APIs for mapping services from Yahoo and Google, as well as receiving live data streams from different sources. A number of custom controls were developed and integrated into the application, including altitude and rotation controls. The application can be re-used for any three dimensional map-based visualization such as weather patterns, demographic, political or economic data.

Time and again the same scenario arises. An app is being built and it’s all going fine until the very end when performance issues start to appear.

Optimizing Flash performance is certainly the most boring part of Flash Platform development but it’s a cornerstone without which you, the Flex developer, can not do without.

An app is worth nothing unless you provide that effortless flow of interaction at all times.

There is not too much information on this topic as it is not the most interesting one but here are some simple guidelines that have helped me tremendously over the time, as well as a few great papers.

So far, of all the AMF frameworks I have been a proponent of AMFPHP and RailsAMF. I still don’t know RoR very well (working on it), but I’ve been using PHP for a long time and have grown to love it so AMFPHP was always my natural choice.

Now we have a new player in Flash Remoting arena – ZendAMF. Why should anybody care when AMFPHP was just fine?

A few reasons.

Here is some follow up information from the Flex Camp Chicago ’09 Community Showcase presentation.

If you read one or more of the Pathfinder blogs in our web interface, you may have noticed some tweaks to our navigation and top-level categories. Our goal in making these changes was to help different audiences drill down to the specific content that interests them. Instead of just a few top-level categories, we now boast around 20, though many posts appear in multiple categories. To subscribe via RSS to any specific category – or to our entire feed – just visit our Feeds page.

Recently I’ve been working on a Flex prototype using the PureMVC framework. I will talk at length another time about just how much PureMVC successfully solves a lot of problems that we encounter in interface development and especially about how much this framework is important for all those complex interactions that we expect out of our RIA interfaces.

Starting out with PureMVC is not a particularly easy task. It is a good thing that there are decent documentation and examples, at least for AS3. At first when I read the documentation, it made sense only on a high level, but translating that high level understanding to code right away was out of the question. I solved this initial sticking point by looking at a couple of AS3 examples like CafeTownsend and EmployeeAdmin, where you can see how the framework works on the right size demo app, not too big and not too small.

At Pathfinder we do a fair amount of desktop style development — iPhone/Cocoa, WebForms, Swing — and web application development — Grails, Rails, JSP, ASP.NET, etc., etc.. In the last two years we, like a lot of other software development shops, have experienced a convergence in our efforts. The web is coming to the desktop in the form of Air and the Desktop is coming to the web in the form of RIA’s. Now web MVC, which used to be a pretty benign pattern mostly concerned with app flow and validation, is starting to resemble desktop MVC, which has to deal with document-centric models and long lived views and all of the plumbing that requires.

So we recently had a powwow between all the different parties to talk about MVC and this convergence. With the exception of the insufferable Mac and iPhone developers and their disgustingly mature Cocoa framework, we all agreed it would be nice to have an application level MVC framework for each platform. We also agreed that Swing is a great example of what happens when the vendor doesn’t provide such a thing — spaghetti code that relies on component level MVC and hard wiring at the application level. There are a few MVC frameworks for Swing, such as TikeSwing and Spring Rich Client (soon to be superseded by Spring Desktop), but for every Swing app that has this sort of design, there are hundreds that are just a mess.

The purpose of this demonstration is to use Yahoo Map and Papervision3D as a base for creating/importing 3D Objects with reference to actual locations on planet Earth using the Adobe Flex framework.

In this post I will be covering how to integrate Yahoo Maps AS3 API as an Interactive Material in PV3D 2.0 and solutions to the following problems:

- Security sandbox violation when using Yahoo Map as MovieMaterial (i.e. BitmapData.draw problem)
- Mapping Longitude and Latitude values to X and Y coordinates of a PV3D material
- Dragging Yahoo Map in PV3D (avoiding the map panning collision with PV3D)
- Simple gauge component from the ground up using basic trigonometry
- Simple tilt component again using basic trigonometry
- Making a visual component using Degrafa

Demonstrations of these solutions are packed in this air application for which you can also see and download fully functioning source code.

I haven’t tried to hide my ambivalence about Adobe’s move into the RIA market. That’s why I feel duty-bound to share my positive experience with a newish AIR application: Tumblweed, a desktop client for the Tumblr micro-blogging service.

Currently in beta release, with new iterations coming quickly, Tumblweed lets you post photos, quotes, links, audio and full blog posts – any of Tumblr’s supported content types – without hitting your browser. None of this would be possible, of course, without Tumblr’s http-based API. But props to Tumblweed creator David Merino for building an application that’s minimalist yet user-centric.

Tumblweed currently supports a subset of the functionality you can access on-site. You can create posts, though editing or deleting them appears to be wonky (at least on my machine, a MacBook Pro running OS X Tiger). You can drag-and-drop photos instead of using a clunky, web-based upload mechanism. You can even copy images directly from the clipboard.

It would be nice if Tumbleweed provided better visual feedback about the image currently being uploaded. I expect such usability issues to improve in subsequent releases. In the meantime, thoughtful touches abound. For instance, the Snapshot dialog lets me take a photo using my Mac’s built-in camera and upload it to Tumblr just like any other photo.

As a blogging client, Tumblweed already delivers value. As a showcase for AIR, it overcame my cautious cynicism about Adobe. The melding of webapp and desktop capabilities proves as compelling in practice as it did in theory at last year’s Adobe MAX conference. It pains me to admit it, but I find myself eager to build an AIR app of my own.