Java-JFormattedTextField AddActionListener

Question

I've been learning a bit more related to Java GUIs. However, I've encountered an problem and am unsure of how to fix it.

I have a part of my program (displayed below, but irrelevant code has been removed), and everything aside from the JFormattedTextField variable (sliderField) works. What I am trying to do is make it so if a value is typed into sliderField that is greater than 5000, and the panel refreshes (already done elsewhere), the field will change to 5000. However, for some reason, actionPerformed doesn't seem to register any sort of change in my JFormattedTextField, also preventing the variable from being changed.

Here is my code:

public class testMenu extends JPanel implements ActionListener, ChangeListener {
    public testMenu(GUI p) {
        parent = p;
        setLayout(new FlowLayout(FlowLayout.LEFT, 10, 0));
        createPanel();
        setVisible(true);
    }

    public void createPanel() {
        createOptions();
    }

    private void createOptions() {
        options[0] = new JPanel();
        add(options[0]);

        options[1] = new JPanel();
        add(options[1]);

        options[2] = new JPanel();
        add(options[2]);

        options[3] = new JPanel();
        add(options[3]);

        options[4] = new JPanel();
        add(options[4]);

        slider = new JSlider(0, 5000, 0);
        slider.setPaintTicks(true);
        slider.setValue(parent.variable);
        slider.addChangeListener(this);
        sliderField = new JFormattedTextField(NumberFormat.getInstance());
        sliderField.setText(Integer.toString(parent.variable));
        sliderField.setColumns(4);
        sliderField.addActionListener(this);

        options[5] = new JPanel();
        options[5].add(new JLabel("Slider Value:"));
        options[5].add(slider);
        options[5].add(sliderField);
        options[5].setVisible(false);

        add(options[5]);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == sliderField) {
            int size = Integer.parseInt(sliderField.getText());
            System.out.println(size);
            if (size > 5000) {
                sliderField.setText("5000");
                size = 5000;
            }
            parent.setVariable("" + size);
        }
    }

    private GUI parent;

    private JSlider slider;
    private JFormattedTextField sliderField;

    private JPanel[] options = new JPanel[5];
}

My question is simple: Why is actionPerformed not registering any sort of action being done on the JFormattedTextField, and how can I fix it?

Also, how would I set up my JFormattedTextField so if a value is put in that is greater than 999, no commas are added (preventing 1000 from displaying as 1,000)?

Answer 1

To get rid of the commas, just use a formatter that doesn't allow them. eg,

  NumberFormat format = NumberFormat.getInstance();
  format.setGroupingUsed(true);  // *** set it so it doesn't use a grouping ***
  final JFormattedTextField formattedField = new JFormattedTextField(format);
  formattedField.setColumns(10);

As for your other problem, what if you get and set the value rather than the text?

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.NumberFormat;

import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;

public class TestJFormattedText {
   public static void main(String[] args) {
      NumberFormat format = NumberFormat.getNumberInstance();
      format.setGroupingUsed(false);
      final JFormattedTextField formattedField = new JFormattedTextField(format);
      formattedField.setColumns(10);

      formattedField.addActionListener(new ActionListener() {

         @Override
         public void actionPerformed(ActionEvent arg0) {
            long value = ((Long)formattedField.getValue()).longValue();
            if (value > 5000) {
               formattedField.setValue(5000);
            }
         }
      });


      JPanel panel = new JPanel();
      panel.add(formattedField);
      JFrame frame = new JFrame("Foo");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.add(panel);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }
}

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An advantage of using values is that you avoid the pesky NumberFormatExceptions if the text held by the JFormattedTextField are not appropriate, do not conform to the formatter.

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As an aside, your code posted in your question contains quite a bit of code unrelated to your problem, and does not compile or run for us. In the future, consider posting only code that is required to both show the problem and to allow the code to run, kind of like what I posted above.

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Edit
You ask in comment,

How can I make it so I do not need to hit 'Enter' for the actionEvent to execute?

You can't as that's how ActionListeners work for JTextFields and for classes derived from JTextFields. I suppose you could add a DocumentFilter to the JFormattedTextField's Document if you want to fiddle with the field's contents before it is displayed in itself, but while I've used these with JTextFields, I've never used them with Documents used with JFormattedTextFields and cannot say that I know from experience that this will work.