For my work I’ve been working with Adobe Flex. If you’re doing Flex development you (probably) work with Flex Builder. It has features a development tool should provide; code completion, design view, good integrated building/running of projects, debugging etc.
At work I’m tied to my Windows XP laptop, at home I work with Ubuntu Linux. Whenever I do Flex development in private time, I always use the Windows machine… but what if you’d like to develop Flex on Linux?
Google quickly pointed to Flex Builder Linux. ‘Yey! A Linux Flex builder!’ The release notes shows some (minor) inconveniences:
Unsupported Flex Builder Features
- Design view
- States view
- Refactoring
- Data Wizards
- Cold Fusion – Data Services Wizard
- Web Services introspection
- Profiler
And some known issues:
- Organize Imports removes necessary imports
- The default version of Java installed in Ubuntu systems is GCJ. This is not supported by the Flex Builder Linux installer and the installation may fail on Ubuntu Systems. Please ensure you have an installed Sun JRE before installing Flex Builder Linux.
- Getting a transparent window for AIR App depends on your Linux distro capabilities. You may need to turn-on some settings (ex: Desktop effects on Ubuntu 7.10) or install some special packages (example: compiz-fusion, beryl for installing compositing manager) to get this working (if its not working by default)
I left out anything not related to Ubuntu or Flex Builder in general. Besides the ‘design view’ most issues are minor issues. Usually the ‘design view’ is used for some initial drag and drop interface building or for containers with and ‘absolute’ layout (i.e. Canvas). The ‘design view’ then limits the build/run/change cycles.
Installing Flex Builder on Ubuntu 9.04
The prerequisites mentioned by Adobe are
- Eclipse 3.3.x (32-bit)
- Sun JRE 1.5.x or newer (32-bit)
- Firefox 1.0, 1.5, or 2.0 (32-bit)
At the moment of writing, the version of Eclipse provided with Ubuntu is 3.2.x. So you’ll have to get a newer Eclipse version from Eclipse.org. I tried the latest version available, which is 3.4.2 (which later turned out to be a bad idea, use a 3.3.x version). Installation of Eclipse is as easy as unpacking to the desired location, so I’m not describing that any further. Make sure you have the Sun JRE 1.5.x or newer installed. I installed ‘sun-java6-jdk’ via the package manager, the JDK includes the JRE. Configure Eclipse to use that.

JRE settings Eclipse
Download the Flex Builder Plugin for Linux.
Installing Flex Builder Linux
To install Flex Builder Linux:
- Prior to installing, remove any previous versions of Flex Builder Linux. Refer to the section ‘Uninstalling Flex Builder Linux’ below for instructions.
- Run the installer either marking it as executable (chmod +x) or by using a shell to execute it (sh FlexBuilder_Linux_Plugin.bin).
- Accept the license agreement and follow the prompts.
- When prompted, specify whether to install Flash Player 9 (note that this is an updated version of Flash Player 9 and that Flex Builder Linux will work with earlier versions of Flash Player 9 for Linux). This is the debug version of Flash Player 9, which is required for debugging support and exception display.
- Follow the prompts to complete the installation.
- Start Eclipse.
Note: You must create a new workspace before beginning. Select File > Switch Workspace from the menu bar and enter a new folder name. If the folder doesn’t exist, Eclipse creates it.

Install Folder
When choosing the ‘install folder’ you can leave that to default, the Eclipse folder will be defined in the next window.

Eclipse Folder
As described select the Eclipse folder, it must contain a subfolder named ‘configuration’. Continue the installation untill the installer displays that you’re done.
Start Eclipse and open the Flex perspective. If you get the following error while opening a MXML file:
Could not open the editor: Assertion failed: org.eclipse.jface.util.Assert$AssertionFailedException: Assertion failed
Make sure you have the correct Eclipse version, I used 3.3.2 on Ubuntu 9.04.

Flex Builder in Linux with code completion
It seems Flex Builder accepts Flex 3 license keys, which is then ignored as it still displays “Flex Builder Linux will expire in xxx days.” If you use charting you can enter your license to remove the trial message.
You already choose to use the trail period and didn’t enter your license key? Open ‘license.properties’ in ‘home/username/.adobe/Flex’. And add:
flexbuilder3=yourlicensekey
Or change:
flexbuilder3.displayedFirstLaunchMessage=true
to:
flexbuilder3.displayedFirstLaunchMessage=false
Restart Flex Builder and enter your license key in the launch message.