Communication between JOptionPane buttons and a custom panel

Question

I have made a multiple input dialog by building a JPanel with the fields I want and adding it to a JOption pane

JMainPanel mainPanel = new JMainPanel(mensaje, parametros, mgr);

int i = JOptionPane.showOptionDialog(null, mainPanel, "Sirena",
        JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE, null,
        new String[] {"Aceptar", "Cancelar"}, "Aceptar");

However I'm having trouble with the buttons, because some of the fields are required. How can I make the "Ok" button to be enabled once every required field is up, or making the click on the button to make the validations and do not close the pane until every required field is filled?

From the Java API, I found this:

options - an array of objects indicating the possible choices the user can make; if the objects are components, they are rendered properly; non-String objects are rendered using their toString methods; if this parameter is null, the options are determined by the Look and Feel

So, can't I pass custom buttons as parameter?

Looks like I will have to make my own JDialog? for which case, I don't know how to make it return an int just like JOptionPane does, any recommended tutorial?

In the example options is {"Aceptar", "Cancelar"} which are the displayed buttons,

PS. I have full controll over the fields I added to the JPanel.

This is a screenshot of the JOptionPane:

Answer 1

I don't think that you can de-activate a JOptionPane's selections buttons, but one way to still use the JOptionPane is to simply re-display it if the required fields have not been set. You could display an error message JOptionPane first describing the error, and then display a new JOptionPane that holds the same JPanel as its second parameter -- so that the data already entered has not been lost. Otherwise, you may want to create your own JDialog which by the way isn't that hard to do.

Edit
I'm wrong. You can enable and disable the dialog buttons if you use a little recursion.

For example:

import java.awt.Component;
import java.awt.Container;
import java.awt.event.*;
import java.util.HashSet;
import java.util.Set;

import javax.swing.*;

public class Foo extends JPanel {
   private static final String[] DIALOG_BUTTON_TITLES = new String[] { "Aceptar", "Cancelar" };
   private JCheckBox checkBox = new JCheckBox("Buttons Enabled", true);
   private Set<AbstractButton> exemptButtons = new HashSet<AbstractButton>();

   public Foo() {
      JButton exemptBtn = new JButton("Exempt Button");
      JButton nonExemptBtn = new JButton("Non-Exempt Button");

      add(checkBox);
      add(exemptBtn);
      add(nonExemptBtn);
      exemptButtons.add(checkBox);
      exemptButtons.add(exemptBtn);

      checkBox.addActionListener(new ActionListener() {

         @Override
         public void actionPerformed(ActionEvent evt) {
            allBtnsSetEnabled(checkBox.isSelected());
         }
      });

   }

   private void allBtnsSetEnabled(boolean enabled) {
      JRootPane rootPane = SwingUtilities.getRootPane(checkBox);
      if (rootPane != null) {
         Container container = rootPane.getContentPane();
         recursiveBtnEnable(enabled, container);
      }
   }

   private void recursiveBtnEnable(boolean enabled, Container container) {
      Component[] components = container.getComponents();
      for (Component component : components) {
         if (component instanceof AbstractButton && !exemptButtons.contains(component)) {
            ((AbstractButton) component).setEnabled(enabled);
         } else if (component instanceof Container) {
            recursiveBtnEnable(enabled, (Container) component);
         }
      }
   }

   public int showDialog() {
      return JOptionPane.showOptionDialog(null, this, "Sirena",
            JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE, null,
            DIALOG_BUTTON_TITLES, "Aceptar");
   }


   private static void createAndShowGui() {
      Foo foo = new Foo();
      int result = foo.showDialog();
      System.out.println(DIALOG_BUTTON_TITLES[result]);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

This code uses listeners to check the state of a JCheckBox, but you can have listeners (DocumentListeners) listening to text field documents if you desire to know if they have data or not. The code then gets the JRootPane that holds the JCheckBox, then the root pane's contentPane, and all components of the dialog are held by this. It then recurses through all the components held by the dialog. If a component is a Container, it recurses through that container. If the component is an AbstractButton (such any JButton or checkbox), it enables or disables -- except for buttons held in the exempt buttons set.

A better example with document listeners

import java.awt.*;
import java.awt.event.*;
import java.util.HashSet;
import java.util.Set;
import javax.swing.*;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;

public class Foo2 extends JPanel {
   private static final String[] DIALOG_BUTTON_TITLES = new String[] {
         "Aceptar", "Cancelar" };
   private static final int FIELD_COUNT = 10;
   private Set<AbstractButton> exemptButtons = new HashSet<AbstractButton>();
   private JTextField[] fields = new JTextField[FIELD_COUNT];

   public Foo2() {
      setLayout(new GridLayout(0, 5, 5, 5));
      DocumentListener myDocListener = new MyDocumentListener();
      for (int i = 0; i < fields.length; i++) {
         fields[i] = new JTextField(10);
         add(fields[i]);
         fields[i].getDocument().addDocumentListener(myDocListener);
      }

      // cheating here

      int timerDelay = 200;
      Timer timer = new Timer(timerDelay , new ActionListener() {

         @Override
         public void actionPerformed(ActionEvent arg0) {
            checkDocsForText();            
         }
      });
      timer.setRepeats(false);
      timer.setInitialDelay(timerDelay);
      timer.start();

   }

   private void checkDocsForText() {
      for (JTextField field : fields) {
         if (field.getText().trim().isEmpty()) {
            allBtnsSetEnabled(false);
            return;
         }
      }
      allBtnsSetEnabled(true);
   }

   private void allBtnsSetEnabled(boolean enabled) {
      JRootPane rootPane = SwingUtilities.getRootPane(this);
      if (rootPane != null) {
         Container container = rootPane.getContentPane();
         recursiveBtnEnable(enabled, container);
      }
   }

   private void recursiveBtnEnable(boolean enabled, Container container) {
      Component[] components = container.getComponents();
      for (Component component : components) {
         if (component instanceof AbstractButton && !exemptButtons.contains(component)) {
            ((AbstractButton) component).setEnabled(enabled);
         } else if (component instanceof Container) {
            recursiveBtnEnable(enabled, (Container) component);
         }
      }
   }

   public int showDialog() {
      return JOptionPane.showOptionDialog(null, this, "Sirena",
            JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE, null,
            DIALOG_BUTTON_TITLES, "Aceptar");
   }

   private class MyDocumentListener implements DocumentListener {

      public void removeUpdate(DocumentEvent arg0) {
         checkDocsForText();
      }

      public void insertUpdate(DocumentEvent arg0) {
         checkDocsForText();
      }

      public void changedUpdate(DocumentEvent arg0) {
         checkDocsForText();
      }
   }


   private static void createAndShowGui() {
      Foo2 foo = new Foo2();
      int result = foo.showDialog();
      if (result >= 0) {
         System.out.println(DIALOG_BUTTON_TITLES[result]);
      }
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }

}

Answer 2

I suggest you to define some properties into your JPanel extended class, and use PropertyChangeListener to listen the occured changes and enable/disable relative buttons.

Here's an article.

Another issue maybe finding the ok/cancel buttons in the hierarchy of components, since the JDialog is created through JOptionPane and you haven't a reference to the buttons. Here's a useful thread .

You can add a property to a JComponent using putClientProperty method. When changes occurs to a given property a PropertyChanged event is raised.

So in your example you can define a boolean property indicating that required that are inserted into the JDialog. Then add a PropertyChangeListener that when is notified enable/disable the ok button.