JComboxBox events

[cucucur]

hi!! I want to do 3 JComboxBox, the second one depends on the first one value, and the third one depends on the second one.

My problem is when the first one changes I have a AWT-EventQueue-0 Exception.

I suppose my problem will be solved with a "on change" event or similar, does it exist in Java???

Thank you so much!!

users = new JComboBox(user);	
address = new JComboBox();
phone = new JComboBox();
listenerUsers listenUsers = new listenerUsers();
users.addActionListener(listenUsers);

public class listenerUsers implements ActionListener {
		public void actionPerformed (ActionEvent e) {
			ArrayList<String> addr = remoto.returnAdd(conn,RFID.getSelectedItem().toString());
			Object[] Addre = addr.toArray();		   		
			address.removeAllItems();
			for (int i = 0; i<Addre.length; i++){
				address.addItem(Addre[i]);
			}
			listenerAddress listenaddress = new listenerAddress();
			address.addActionListener(listenAddress);
		}
	}
	
	public class listenerAddress implements ActionListener {
		public void actionPerformed (ActionEvent e) {
			ArrayList<String> IBUTTONS = remoto.returnPhone(conn,address.getSelectedItem().toString()); //ERROR
			
		} 
        }

[KevinWorkman]

That's not the Exception, that's simply the Thread that's running when the Exception is thrown. Can you copy and paste the full stack trace with the actual Exception?

Also- how would an "on change" listener be different from an ActionListener?

[camickr]

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;

public class ComboBoxTwo extends JFrame implements ActionListener
{
	private JComboBox mainComboBox;
	private JComboBox subComboBox;
	private Hashtable subItems = new Hashtable();

	public ComboBoxTwo()
	{
		String[] items = { "Select Item", "Color", "Shape", "Fruit" };
		mainComboBox = new JComboBox( items );
		mainComboBox.addActionListener( this );

		//  prevent action events from being fired when the up/down arrow keys are used
//		mainComboBox.putClientProperty("JComboBox.isTableCellEditor", Boolean.TRUE);
		getContentPane().add( mainComboBox, BorderLayout.WEST );

		//  Create sub combo box with multiple models

		subComboBox = new JComboBox();
		subComboBox.setPrototypeDisplayValue("XXXXXXXXXX"); // JDK1.4
		getContentPane().add( subComboBox, BorderLayout.EAST );

		String[] subItems1 = { "Select Color", "Red", "Blue", "Green" };
		subItems.put(items[1], subItems1);

		String[] subItems2 = { "Select Shape", "Circle", "Square", "Triangle" };
		subItems.put(items[2], subItems2);

		String[] subItems3 = { "Select Fruit", "Apple", "Orange", "Banana" };
		subItems.put(items[3], subItems3);
//		mainComboBox.setSelectedIndex(1);
	}

	public void actionPerformed(ActionEvent e)
	{
		String item = (String)mainComboBox.getSelectedItem();
		Object o = subItems.get( item );

		if (o == null)
		{
			subComboBox.setModel( new DefaultComboBoxModel() );
		}
		else
		{
			subComboBox.setModel( new DefaultComboBoxModel( (String[])o ) );
		}
	}

	public static void main(String[] args)
	{
		JFrame frame = new ComboBoxTwo();
		frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
		frame.pack();
		frame.setLocationRelativeTo( null );
		frame.setVisible( true );
	 }
}

[cucucur]

thank you so much for your help. the stack is:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at alquilar$listenerAddress.actionPerformed(alquilar.java:88)
	at javax.swing.JComboBox.fireActionEvent(Unknown Source)
	at javax.swing.JComboBox.contentsChanged(Unknown Source)
	at javax.swing.JComboBox.intervalRemoved(Unknown Source)
	at javax.swing.AbstractListModel.fireIntervalRemoved(Unknown Source)
	at javax.swing.DefaultComboBoxModel.removeAllElements(Unknown Source)
	at javax.swing.JComboBox.removeAllItems(Unknown Source)
	at alquilar$listenerUsers.actionPerformed(alquilar.java:77)
	at javax.swing.JComboBox.fireActionEvent(Unknown Source)
	at javax.swing.JComboBox.setSelectedItem(Unknown Source)
	at javax.swing.JComboBox.setSelectedIndex(Unknown Source)
	at javax.swing.plaf.basic.BasicComboPopup$Handler.mouseReleased(Unknown Source)
	at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
	at java.awt.Component.processMouseEvent(Unknown Source)
	at javax.swing.JComponent.processMouseEvent(Unknown Source)
	at javax.swing.plaf.basic.BasicComboPopup$1.processMouseEvent(Unknown Source)
	at java.awt.Component.processEvent(Unknown Source)
	at java.awt.Container.processEvent(Unknown Source)
	at java.awt.Component.dispatchEventImpl(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Window.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.awt.EventQueue.access$000(Unknown Source)
	at java.awt.EventQueue$1.run(Unknown Source)
	at java.awt.EventQueue$1.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
	at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue$2.run(Unknown Source)
	at java.awt.EventQueue$2.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.run(Unknown Source)

Regards!

[cucucur]

hi! switch?? I'm afraid I don't understand you...

[DarrylBurke]

Ignore the spammer, I've already reported it and those meaningless posts will go away shortly.

db