How to force a double input in a TextField in JavaFX?

Question

How to make sure an user inputs only double values in a given TextField?

I found a solution for integers bu I can\'t manage to use it for doubles.

Answer 1

You can use the java regex on doubles and replace non-number characters with numbers. In you have to specify the number of digits allowed in the integer part, for example 1,10.

textField.textProperty().addListener(new ChangeListener() {
    @Override
    public void changed(ObservableValue observable, String oldValue, String newValue) {
        if (!newValue.matches("[0-9]{}(\\.[0-9]*)?")) {
            textField.setText(newValue.replaceAll("[^\\d.]", ""));
            StringBuilder aus = new StringBuilder(newValue);
            boolean firstPointFound = false;
            for (int i = 0; i < aus.length(); i++){
                if(aus.charAt(i) == '.') {
                    if(!firstPointFound)
                        firstPointFound = true;
                    else
                        aus.deleteCharAt(i);
                }
            }
            newValue = aus.toString();
        }
    }
});