CNIC formator in flutter
class NumberTextInputFormatter extends TextInputFormatter {
@override
TextEditingValue formatEditUpdate(
TextEditingValue oldValue, TextEditingValue newValue) {
final int newTextLength = newValue.text.length;
int selectionIndex = newValue.selection.end;
int usedSubstringIndex = 0;
final StringBuffer newText = new StringBuffer();
if (newTextLength >= 6) {
newText.write(newValue.text.substring(0, usedSubstringIndex = 5) + '-');
if (newValue.selection.end >= 5) selectionIndex += 1;
}
if (newTextLength >= 13) {
newText.write(newValue.text.substring(5, usedSubstringIndex = 12) + '-');
if (newValue.selection.end >= 12) selectionIndex += 1;
}
// Dump the rest.
if (newTextLength >= usedSubstringIndex)
newText.write(newValue.text.substring(usedSubstringIndex));
return new TextEditingValue(
text: newText.toString(),
selection: new TextSelection.collapsed(offset: selectionIndex),
);
}
}