Specifications

CHAPTER 11

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}

]]></mx:Script>

<mx:Label text="{reportVersion()}"/>

<mx:Label text="{reportType()}"/>

</mx:Application>

Other properties of the Capabilities class include hasPrinting, os, and language.

Client-side logging and debugging

Often, you use the trace() method when you debug applications to write a checkpoint message on the client,

which signals that your application reached a specific line of code, or to output the value of a variable.

The debugger version of Flash Player has two primary methods of writing messages that use trace():

• The global trace() method. The global trace() method prints Strings to a specified output log file. For

more information, see

“Using the global trace() method” on page 232.

• Logging API. The logging API provides a layer of functionality on top of the trace() method that you can

use with your custom classes or with the data service APIs. For more information, see

“Using the logging API” on

page 233.

Configuring the debugger version of Flash Player to record trace() output

To record messages on the client, you must use the debugger version of Flash Player. You must also set

TraceOutputFileEnable to 1 in your mm.cfg file. For more information on editing the mm.cfg file, see “Config-

uring the debugger version of Flash Player” on page 229.

The debugger version of Flash Player sends output from the

trace() method to the flashlog.txt file. The location

of this file is determined by the operating system. For more information, see “Log file location” on page 231.

Using the global trace() method

You can use the debugger version of Flash Player to capture output from the global trace() method and write

that output to the client log file. You can use

trace() statements in any ActionScript or MXML file in your appli-

cation. Because it is a global function, you are not required to import any ActionScript classes packages to use the

trace() method.

The following example defines a function that logs the various stages of the Button control’s startup life cycle:

<?xml version="1.0"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">