Control keyboard input into javafx TextField

Question

I want to control the input into a Javafx TextField so that I can allow only Numeric input, and so that if the max characters are exceeded, then no change will be made to th

Answer 1

Here is my aproach, two event filters, could be one, in my case i used them in diferent situations, thats why there are two.

Here is the maxValueFilter (in spanglish xD), this one is a class:

public class FilterMaxValue implements EventHandler {

        private int maxVal;

        public FilterMaxValue (int i) {
            this.maxVal= i;
        }

        public void handle(KeyEvent arg0) {

            TextField tx = (TextField) arg0.getSource();
            String chara = arg0.getCharacter();
            if (tx.getText().equals(""))
                return;

            Double valor;
            if (chara.equals(".")) {
                valor = Double.parseDouble(tx.getText() + chara + "0");
            } else {
                try {
                    valor = Double.parseDouble(tx.getText() + chara);
                } catch (NumberFormatException e) {
                    //The other filter will prevent this from hapening
                    return;
                }
            }
            if (valor > maxVal) {
                arg0.consume();
            }

        }
    }

And the other event filter (filters the chars), this one is a method:

public static EventHandler numFilter() {

        EventHandler aux = new EventHandler() {
            public void handle(KeyEvent keyEvent) {
                if (!"0123456789".contains(keyEvent.getCharacter())) {
                    keyEvent.consume();

                }
            }
        };
        return aux;
    }

the use in your case would be:

field.addEventFilter(KeyEvent.KEY_TYPED,
                numFilter());
field.addEventFilter(KeyEvent.KEY_TYPED, new FiltroValorMaximo(
                99));