Hello,
someone might remember an older post on Beautify Code which has shown how to successfully create an AIR application certificate, publish the project and then package it to an .air file, which can be installed and run. Now here's the 2010 update, working with AIR2 and FDT4 (using an ANT-Build) and some major changes.

Table of Content:

1. Introduction
2. Required Downloads
3. Creating an AIR2 Project in FDT4
4. Application Descriptor
5. A powerful ANT-Build
6. Digitally Signing / Certificates
7. Most Common Errors
8. Summary & Sample-Project

Introduction:

Creating an AIR-Application requires different tasks. First of all we need to publish an SWF which represents our content. Secondly we need to create a certificate and at last we have to package the application into an .air file. By going through these three steps you will get known to an Application Descriptor, a very handy ANT-Build file, creating a certificate and what most of these really cryptic error messages mean. In the end you are able to release an AIR application with FDT 4 which can be quickly compiled as an Android-App or a Webdeploy as well by just changing the Descriptor.

Required Downloads:

Okay, firstly everybody get FDT4. Seriously, you cannot find anything better out there. :) The only thing what bothered me most at FDT4 was the still remaining bad workflow concerning AIR-Applications. Now I know better and as you can imagine - after writing this article I can't even complain anymore.

Secondly, you need a Flex SDK which supports AIR 2. I am currently working with 4.1.0.16076. Download it on Adobe Open Source and unpack it somewhere you like to. I prefer sticking my SDKs together so I've taken FDT's plugins/ folder which already contains the shipped ones.

Besides we need an iconpackage containing different sizes so we can use them as tray- and applicationicon. Download AIRTest_assets.zip and unpack the assets folder to your project's root directory. There is already set up a settings folder within, which later will be used for our certificate - so just keep it.

Creating an AIR2 Project in FDT4:

Thankfully FDT4 implemented Project Templates which easily allows us to create an AIR Project. Well, sounds good. Unfortunately the current build (maybe they'll change it till release) uses the Flex 4.0 SDK which does not support AIR 2. That means we have to change the SDK but luckily again this has been simplified a lot as well in FDT4. The following screenshots demonstrate how to add a new SDK and then chose it for the new project.

Create a new project with the desktop AIR Application template using Flex 4. Give it a name, specify your project location and continue by pressing "Next". On the following screen you see the already installed SDKs which have been shipped with FDT4. By clicking on "Add" you can install a new one - in our case Flex 4.1.











Specify the SDK directory, which will make FDT to initialize the containing swc files. As it's finished, give your SDK a name and confirm with "Okay". Close the "Installed SDKs" window and you are back at the project settings where you can chose your new SDK in the pulldown. If everything went fine you now should see that this SDK is supporting AIR 2.0.2.

Finally there has been a new AIR project created on our workspace and we're ready to set up a class to be compiled. So as we all know: Rightclick on your src folder, create new AS3 class and so on. Here's mine:

So this is it. This is the file we're going to compile to our AIR-Application!

The Application Descriptor:

To publish an .air file we always need writing a description file for our application first - by the way it's common this file is called the Application Descriptor. It always looks pretty similar as it's an XML file with descriptive nodes. Each node specifies an application's property like name, id, the initial window's size, whether it's transparent or not, the taskbar icons and all the like. Every AIR application needs them and therefore you can work with a template and adjust the values. By standard you name this .xml file the same as your project and add an -app to it. So in my case it's named AirTest-app.xml.

Create a new XML file on your project's root directory, name it appropriately like told above, paste in the following code and edit the properties as you want. Don't forget to change the content-property!

➔ See AirTest-app.xml

A powerful ANT-Build:

For the purpose to combine the mentioned tasks (publish / create certificate / package) we need a lot of compiling commands to be executed after another. The easiest way to do so is working with an ANT Build as it uses JAVA to run mxmlc and adt, which is both necessary for compiling an AIR file. Using ANT is really simple in FDT as you only have to open the ANT view (either you have once minimized it, then it's an icon at the most left bar in FDT4 or you have closed it - in that case you can go to Window > Show View > ANT and reposition it to where you like to).

Now we need the ANT file which contains all this magic, don't we?

➔ Download buildAIR2_ant.zip and extract it to your project's root directory. This file is most essential in this project so I will talk about it a bit in detail. But first of all let's simply drag & drop the buildAIR2.xml into the ANT window:

As you can see there are now different tasks you can execute by just doubleclick on them. But before doing we have a bit to set it up regarding to your project. Open the buildAIR2.xml in FDT so we can edit the file itself. Don't be scared - although the file is pretty long you do not have to change more than one or two lines. Let's have a look at them (18-29) and on what to change there:

Most important is the path to your Flex SDK. Please make double-sure it is correct. Then very essential to change as well is your Application Name - as this has exactly to be the same as your Main-Class! Last but not least you obviously have to change "adl.exe" to "adl" as a Mac user. The following lines depend on the certificate. We will have a look on that later - for now the set values are okay. Now let's see some action and see what each task does in real.

1. Cleanup Directories

This is the default task. It removes old compiles / publishes / settings from previous packagings. So at the moment it simply does nothing.

2. Build New Directories

This task is always called before any compile (either SWF or AIR) saves the file. Because otherwise JAVA would just throw an error when trying to access a non-existing directory. When doubleclicking it the following pops out of your console:

And when refreshing your filebrowser you notice these new three folders. Isn't that cool? I could doubleclick this task the whole day over and over again, but well.. Maybe after finishing this article. However, I think the foldernames are pretty self-explaining.

3. Compile SWF

By executing this task you finally create a SWF based on your AS3 Class file. It will be stored in the /publish directory. If you have set up everything correctly this is the first step where you can see if everything works so far. The best indication for that is this console output:

Refresh your filebrowser and check if there is a new .swf file in your /publish folder.

4. Compile SWF (Debug)

Same thing but published with debug-capability to /debug directory.

5. Test Application

Yea - this is the first time AIR comes into play. When doubleclicking this task a debuggable SWF file is compiled and opened with the Adobe AIR Launcher. As we all know it directly works and any traces are executed and shown in the FDT console. Cool, he?

6. Package Application

Now here comes all the important stuff together. A non-debuggable SWF file will be compiled and then the ADT - AIR Development Tool - is launched with many, many options. These options are equal to the values you've declared in your Application Descriptor and the ANT build's certificate settings. When starting it without having a certificate created first it will throw errors like:

7. Create New Certificate

This task does what it's called like. The options (like password / encryption / name / where to save / ...) can be changed in the ANT Build itself (see above). The certificate file will then be stored in the assets/settings directory.

➔ See buildAIR2.xml

Digitally Signing / Certificates:

Using a certificate is required when publishing an AIR application as it contains every identity's, owner's and location's information. In our case setting this up doesn't take too long. In our buildAIR2.xml there are two paragraphs for these settings. One for using an existing certificate by authorizing with it's name & password and one for writing a new one, with a name, password and the required data. The ANT Build is appropriately commented on this:

As you can see the AIR file even works with any information. After we've created a new one with the 7th build task the same certificate is used (see name and password) to be packaged with the AIR file. Make sure to create a new certificate for every AIR application.

Publisher unknown / Application unverified

If you're just getting started with Adobe AIR and don't want to shell out money, you can always sign your application with an untrusted certificate to allow the AIR runtime to install your application as UNVERIFIED publisher to get you through your testing cycle.

That means if you're going to be a verified publisher you have to buy an AIR development certificate (priced around 300$ a year). So for everyone interested in trustfully signing his applications, here's a comprehensive article on How to get a certificate? by Adobe.

Most Common Errors:

While packaging:

Solution: This is by far the most happening error. Okay, there are two things you have to check. First: Did you really link the new SDK in your ANT build? Second: Is this SDK Flex 4.1?

Solution: Your SDK path is not correct.


While creating a certificate:

Solution: Create a settings folder in your assets directory.


While starting the .air file:

Solution: Okay, I've heared of that and even seen that once. What I did then was changing the JRE and package it again.

Summary & Sample-Project:

Okay, we're done. After executing the 7th and then the 6th task there should appear the following output in your console:

An .air file is stored in the publish/ directory. Doubleclick it and an installer pops up - there we go :) Hopefully I could lead you to the same result I've got. If not feel free to ask any questions. You can take my project-files if you like to but keep in mind to change the mentioned values.

➔ Download AirTest_project.zip




Chek the follow-up articles as well:
➔ Use SWC files within your ANT Build (known as Linked Resource)
➔ Use source folders within your ANT Build (known as Linked Resource)
➔ Chromeless Designs - A Designer's Look