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

the best way is :

    @FXML
private TextField txt_Numeric;
@FXML
private TextField txt_Letters;

@Override
public void initialize(URL url, ResourceBundle rb) {
    /* add Event Filter to your TextFields **************************************************/
    txt_Numeric.addEventFilter(KeyEvent.KEY_TYPED , numeric_Validation(10));
    txt_Letters.addEventFilter(KeyEvent.KEY_TYPED , letter_Validation(10));
}

/* Numeric Validation Limit the  characters to maxLengh AND to ONLY DigitS *************************************/
public EventHandler numeric_Validation(final Integer max_Lengh) {
    return new EventHandler() {
        @Override
        public void handle(KeyEvent e) {
            TextField txt_TextField = (TextField) e.getSource();                
            if (txt_TextField.getText().length() >= max_Lengh) {                    
                e.consume();
            }
            if(e.getCharacter().matches("[0-9.]")){ 
                if(txt_TextField.getText().contains(".") && e.getCharacter().matches("[.]")){
                    e.consume();
                }else if(txt_TextField.getText().length() == 0 && e.getCharacter().matches("[.]")){
                    e.consume(); 
                }
            }else{
                e.consume();
            }
        }
    };
}    
/*****************************************************************************************/

 /* Letters Validation Limit the  characters to maxLengh AND to ONLY Letters *************************************/
public EventHandler letter_Validation(final Integer max_Lengh) {
    return new EventHandler() {
        @Override
        public void handle(KeyEvent e) {
            TextField txt_TextField = (TextField) e.getSource();                
            if (txt_TextField.getText().length() >= max_Lengh) {                    
                e.consume();
            }
            if(e.getCharacter().matches("[A-Za-z]")){ 
            }else{
                e.consume();
            }
        }
    };
}    
/*****************************************************************************************/

Best of luck.