Text field formatters

Formatters are used with JFormattedTextField components to convert textual input into other types of objects, including numbers. When you build your UIs programmatically the easiest way to install formatters is to supply them to JFormattedTextField’s constructor as arguments:

from javax.swing import JFormattedTextField
from java.text import DecimalFormat

someNumericField = JFormattedTextField(DecimalFormat('0.00'))

However, when you build your UI declaratively, like with UI designer tools such as JFormDesigner, you cannot change the way the fields are instantiated. This module lets you easily install formats in formatted text fields afterwards.

This example installs a date format in a formatted text field using installFormat():

from java.text import SimpleDateFormat
from swingutils.format import installFormat

installFormat(startDateField, SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ"))

Numeric formatters

When formatting numbers, you often want to specify the minimum and maximum number of digits before and after the decimal point. For this reason, the formatting module offers the installNumberFormat() function:

from java.lang import Double
from swingutils.format import installNumberFormat

installNumberFormat(someNumericField, Double, maximumFractionDigits=2)

If you give a Python numeric type as the type parameter, it will pick the corresponding Java numeric type as the output type according to the following table:

Python type	Java type
int	Long
long	BigInteger
float	Double
decimal	BigDecimal