TextField that accepts only positive numbers - JavaFX - javafx

Question

I'm trying to create a TextField in JavaFX (using Scene Builder) that accepts only positive numbers.
I'm trying actually to make a TextField for a 'Credit Card Number' which accepts 13 - 16 numeric values, not including the minus sign at the beginning, and which can accept 0 at the beginning of the text.
Also, since it's a 'Credit Card Number' TextField, I'm looking for a way where I can insert automatic space after each 4 letters/numbers inserted to it.
Note: I know how to create a TextField that accepts only numbers but it also accepts minus sign at the beginning and doesn't accept the 0 as the first input.

Answer 1

Here is what I have been using so my TextField only accepts digits and it works like a charm as below,
public static void digitsTxtFld(TextField field) {
field.setTextFormatter(new TextFormatter<Integer>(change -> {
String newText = change.getControlNewText();
if (newText.matches("\\d*")) {
return change;
}
return null;
}));
}
And to set a character limit I use this,
public static void setTextLimit(TextArea textArea, int length) {
textArea.setTextFormatter(new TextFormatter<>(change -> {
String string = change.getControlNewText();
if (string.length() > length) {
textArea.positionCaret(string.length());
return change;
} else {
return null;
}
}));
}
Edit:
Apparently one cannot have both text formatters as the second one you call will replace the first and your field will only run with one at a time. So I made a joint formatter as follows:
public static void setTextLimitToDigitFld(TextField field, int length) {
field.setTextFormatter(new TextFormatter<Integer>(change -> {
String newText = change.getControlNewText();
if (newText.matches("\\d*") && newText.length() > length) {
return change;
}
return null;
}));
}