[FIXED] How to set JSpinner to display "Infinite" when the value is -1?

Issue

I have a JSpinner and it counts down from n to 0. However, if the value is -1, I want that number to be hidden and instead display "Infinite" or "∞" instead. When I retrieve the value, it'll still read as -1.

Is this possible, and by using a SpinnerNumberModel?

Thanks,

Ant

Solution

You can implement your own AbstractFormatter for the JFormattedTextField of the DefaultEditor of the JSpinner. This is responsible for converting Strings to values and values to Strings.

Here is some sample code with the custom formatter solution:

import java.text.ParseException;
import java.util.Objects;
import javax.swing.JFormattedTextField;
import javax.swing.JFormattedTextField.AbstractFormatter;
import javax.swing.JFormattedTextField.AbstractFormatterFactory;
import javax.swing.JFrame;
import javax.swing.JSpinner;
import javax.swing.JSpinner.DefaultEditor;
import javax.swing.SpinnerNumberModel;

public class FormatterMain {

    public static class CustomFormatter extends AbstractFormatter {
        private static final String INFINITE_TEXT = "Infinite";
        private static final Object INFINITE_VALUE = -1;

        @Override
        public Object stringToValue(final String text) throws ParseException {
            try {
                if (Objects.equals(text, INFINITE_TEXT))
                    return INFINITE_VALUE;
                return Integer.valueOf(text);
            }
            catch (final NumberFormatException nfx) {
                //Find where in the string is the parsing error (so as to return ParseException accordingly).
                int i = 0;
                for (final int cp: text.codePoints().toArray()) {
                    if (!Character.isDigit(cp))
                        throw new ParseException("Not a digit.", i);
                    ++i;
                }
                //Should not happen:
                throw new ParseException("Failed to parse input \"" + text + "\".", 0);
            }
        }

        @Override
        public String valueToString(final Object value) throws ParseException {
            if (Objects.equals(value, INFINITE_VALUE))
                return INFINITE_TEXT;
            return Objects.toString(value);
        }
    }

    public static class CustomFormatterFactory extends AbstractFormatterFactory {
        @Override
        public AbstractFormatter getFormatter(final JFormattedTextField tf) {
            if (!(tf.getFormatter() instanceof CustomFormatter))
                return new CustomFormatter();
            return tf.getFormatter();
        }
    }

    public static void main(final String[] args) {
        final JSpinner spin = new JSpinner(new SpinnerNumberModel(0, -1, Integer.MAX_VALUE, 1));

        ((DefaultEditor) spin.getEditor()).getTextField().setFormatterFactory(new CustomFormatterFactory());

        final JFrame frame = new JFrame("JSpinner infinite value");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(spin);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

Answered By - gthanop

Answer Checked By - Senaida (PHPFixing Volunteer)