Thread: Snakes and Ladders

Hi there,

Basically got a small problem with my action listener for a button within a JPanel.

I want to call a method from another class within the action listener however it does not work. Calling the function in the same way works outside of the action listener. I have tried instantiating the class containing the method however this still is not working.

Any help would be greatly appreciated, please see code below.

Thanks

SnakesAndLadders Class:

import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
 
public class SnakesAndLadders
{
	public static void main(String[] args)
	{
		JFrame f=new JFrame();
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		f.setSize(450,450);
 
		final SnakesAndLaddersGUI gui=new SnakesAndLaddersGUI();
		f.getContentPane().add(gui);
		f.setVisible(true);
		final Play play = new Play();
 
		gui.setNumberOfPlayers(1);
        final int[]pos=new int[1];
 
        for(int i=0;i<1;i++)
        {
        	pos[i]=1;
            gui.setPosition(i,0);
        }
        try
        {
			Thread.sleep(1500);
		}
 
		catch(Exception e){e.printStackTrace();}
 
		JFrame frame = new JFrame("Network");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
		JButton roll = new JButton("Roll");
 
		roll.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				Play play = new Play();
				System.out.println("Button Pressed");
				play.roll(pos,gui);
			}
		});
 
		frame.getContentPane().add(roll);
		frame.pack();
		frame.setVisible(true);
	}
}

Play Class:

public class Play
{
	public int roll(int pos[], SnakesAndLaddersGUI gui)
	{
		try
		{
			int dice;
			Thread.sleep(500);
			for(int i=0;i<1;i++)
			{
				dice=(int)(Math.random()*6);
				while(dice>0)
				{
					gui.setPosition(i,pos[i]++);
					dice--;
					Thread.sleep(100);
				}
			}
		}
		catch(Exception e){e.printStackTrace();}
		return 0;
	 }
 
 }

Sorry for not being specific. I have copied the error message shown in the command window below.

is it possible to call a method in another class from the main class i.e:

Main
{
      public void actionPerformed(ActionEvent e)
      {
            Play play = new Play();
             play.roll(pos,gui);
       }
}

pos is an array and gui is used to access a method "setPosition" which is located in another class.


Button Pressed
Exception in thread "AWT-EventQueue-0" java.lang.Error: Cannot call invokeAndWai
t from the event dispatcher thread
at java.awt.EventQueue.invokeAndWait(EventQueue.java: 981)
at SnakesAndLaddersGUI.syncRequestRepaint(SnakesAndLa ddersGUI.java:80)
at SnakesAndLaddersGUI.setPosition(SnakesAndLaddersGU I.java:25)
at Play.roll(Play.java:14)
at SnakesAndLadders$1.actionPerformed(SnakesAndLadder s.java:45)
at javax.swing.AbstractButton.fireActionPerformed(Abs tractButton.java:19
95)
at javax.swing.AbstractButton$Handler.actionPerformed (AbstractButton.jav
a:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed (DefaultButtonModel
.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultB uttonModel.java:242
)
at javax.swing.plaf.basic.BasicButtonListener.mouseRe leased(BasicButtonL
istener.java:236)
at java.awt.Component.processMouseEvent(Component.jav a:6267)
at javax.swing.JComponent.processMouseEvent(JComponen t.java:3267)
at java.awt.Component.processEvent(Component.java:603 2)
at java.awt.Container.processEvent(Container.java:204 1)
at java.awt.Component.dispatchEventImpl(Component.jav a:4630)
at java.awt.Container.dispatchEventImpl(Container.jav a:2099)
at java.awt.Component.dispatchEvent(Component.java:44 60)
at java.awt.LightweightDispatcher.retargetMouseEvent( Container.java:4577
)
at java.awt.LightweightDispatcher.processMouseEvent(C ontainer.java:4238)

at java.awt.LightweightDispatcher.dispatchEvent(Conta iner.java:4168)
at java.awt.Container.dispatchEventImpl(Container.jav a:2085)
at java.awt.Window.dispatchEventImpl(Window.java:2478 )
at java.awt.Component.dispatchEvent(Component.java:44 60)
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 599)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(EventDispatchThre
ad.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(E ventDispatchThread.
java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThre
ad.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:169)

at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:161)

at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:122)

Thanks