JavaFX : TextField max and min value by listener

Question

I need to limit interval of the text property of a text field

int maxLength = 64;
    int minLength = 0;
    txtSeuil.textProperty().addListener((v, oldValue, newValue) -> {
        if (!newValue.matches("\\d*")) {
            txtSeuil.setText(newValue.replaceAll("[^\\d*{1,2}]", ""));
            if (txtSeuil.getText().length() > maxLength || txtSeuil.getText().length() < minLength) {
                String s = txtSeuil.getText().substring(0, maxLength);
                txtSeuil.setText(s);
            }
        }

    });

the field does accept only numbers but any number, not just the interval values

Answer 1

If I have understood correctly, you're trying to implement a number field that only allows values within the interval [0, 64]. According to this answer, TextFormatter is the recommended way to accomplish such a functionality. Have a look at this MWE which should solve your problem:

public class RestrictedNumberFieldDemo extends Application {

    public static void main(String[] args) {
        launch();
    }

    @Override
    public void start(Stage primaryStage) {
        TextField numField = new TextField();
        numField.setTextFormatter(new TextFormatter<Integer>(change -> {
            // Deletion should always be possible.
            if (change.isDeleted()) {
                return change;
            }

            // How would the text look like after the change?
            String txt = change.getControlNewText();

            // There shouldn't be leading zeros.
            if (txt.matches("0\\d+")) {
                return null;
            }

            // Try parsing and check if the result is in [0, 64].
            try {
                int n = Integer.parseInt(txt);
                return 0 <= n && n <= 64 ? change : null;
            } catch (NumberFormatException e) {
                return null;
            }
        }));

        primaryStage.setScene(new Scene(numField));
        primaryStage.show();
    }

}