JSpinner: Increase length of editor box

Question

I have a JSpinner that displays decimal values from 0.0 to 999.0. It seems to work fine, except for when it displays a number in the editor box that is four-digits long, su

Answer 1

As FontMetrics vary from one platform to the next, it's better to rely on the component's own calculation of preferred size. This example shows a spectrum of JSpinner sizes for various min and max values. Note in particular that FlowLayout "lets each component assume its natural (preferred) size."

import java.awt.EventQueue;
import java.awt.FlowLayout;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSpinner;
import javax.swing.SpinnerNumberModel;

/** @see http://stackoverflow.com/questions/7374659 */
public class SpinnerTest extends Box {

    private static final double STEP = 0.1d;
    private static final String FORMAT = "0.0000000000";

    public SpinnerTest(int axis) {
        super(axis);
        for (int i = 0; i < 8; i++) {
            int v = (int) Math.pow(10, i);
            this.add(genParamPanel((i + 1) + ":", -v, v));
        }
    }

    private JPanel genParamPanel(String name, double min, double max) {
        JPanel panel = new JPanel(new FlowLayout(FlowLayout.TRAILING));
        JLabel label = new JLabel(name, JLabel.TRAILING);
        JSpinner js = new JSpinner(new SpinnerNumberModel(min, min, max, STEP));
        js.setEditor(new JSpinner.NumberEditor(js, FORMAT));
        panel.add(label);
        panel.add(js);
        return panel;
    }

    private void display() {
        JFrame f = new JFrame("SpinnerTest");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(this);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new SpinnerTest(BoxLayout.Y_AXIS).display();
            }
        });
    }
}