Programming Flex 3

Using FDB

As part of the Flex SDK, Adobe includes FDB, a free command-line debugger. This debugger is fully featured, although usually you will opt to use the Flex Builder debugger if available. With that said, it is great to have access to a free debugging tool included as part of the SDK. This allows developers who do not want to purchase Flex Builder access to a fully featured debugger. We won’t be covering FDB in depth, but we will discuss the basics and some of the possible benefits it has to offer.

You launch FDB from the command line as you would any other command-line application. Once it is started, you will be prompted with the FDB prompt (fdb). You can type help at the prompt for a list of available commands.

The starting point for a debug session with FDB is to launch an .swf compiled with debugging enabled in the Debug Player and establish a connection with FDB. You do this by first executing the run command at the FDB prompt. Once the command is executed, FDB will confirm that it is waiting for the player to connect. To connect Flash Player to FDB, open a debug-enabled .swf with the Debug Player. When a debug-enabled .swf is opened, the player will attempt to auto-connect to the local debugger, if available. If you open an application without the debugger listening for a connection from the player, the Flash Debug Player will prompt you to select the debugger you want to use. Although typically a user will be running the application and the debugger on the same machine, ...