I ported a very nice component originally written for B4J by Erel:
xRegexField
It checks the input from the user by a regex pattern and shows with a colored border invalid data; it should even "lock" the user to that specific field if invalid data is detected.
Code:
^([0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]$
could be a pattern for HH:MM time