Maya TextField

mayaTextField.py

import maya.cmds as cmds
import re
import functools

def validateTextFieldUserInput(widget, pattern, fallback, callback, input):
    if re.match(pattern, input):
        callback(input)
    else:
        fallback(widget)

def textFieldFloatDefaultFallback(widget, default="0.0"):
    cmds.textField(widget, e=True, text=default)

def myCallback(value):
    print "Gimme Love Baby!", value

window = cmds.window()
cmds.columnLayout()
myField = cmds.textField()
cmds.textField(myField, e=True, changeCommand=functools.partial(validateTextFieldUserInput,
                                                                myField,
                                                                r"[-+]?\d*\.?\d+([eE][-+]?\d+)?",
                                                                textFieldFloatDefaultFallback,
                                                                myCallback))

cmds.showWindow( window )