Programming Flex 3

Formatting Data

The Flex framework provides a group of components that allow you to format values. You can use these formatters to format data for any reason, though they’re most useful for displaying data.

Flex ships with a handful of formatters, such as NumberFormatter and PhoneFormatter, and you can even build custom formatters based on the same framework. Each formatter uses different properties, but all the formatters work in the same basic manner. First you must create the formatter either with MXML or with ActionScript, assigning property values as necessary. Then you can call the format() method of the formatter, passing it the value you want to format. The format() method returns a string. If the formatter can't format a string, it dispatches an error event.

You can create a formatter using MXML with the corresponding MXML tag. For example, the following creates a NumberFormatter instance. This example uses all the default property values, though you could also set the property values in the MXML. Note that you should always assign an id value to formatters because you’ll need to reference them with ActionScript.

<mx:NumberFormatter id="numberFormatter" />

You can optionally create a formatter with ActionScript using the constructor, as shown here:

var numberFormatter:NumberFormatter = new NumberFormatter();

Once you’ve created a formatter object, you must call the format() method to apply the formatting. The format() method requires that you pass it the value you want to format. ...