filterPattern property
final
A Pattern to match or replace in incoming TextEditingValues.
The behavior of the pattern depends on the allow property. If it is true, then this is an allow list, specifying a pattern that characters must match to be accepted. Otherwise, it is a deny list, specifying a pattern that characters must not match to be accepted.
Typically the pattern is a regular expression, as in:
link
FilteringTextInputFormatter onlyDigits = FilteringTextInputFormatter.allow(RegExp(r'[0-9]'));
Implementation
final Pattern filterPattern;