[tanny_]

I have a class which extends a regular JPanel, and then another class from which I would like to add objects to the JPanel to be displayed. I have an external GUI driver which I have verified is working correctly, by creating the objects in the constructor of my JPanel they are visible.

It seems that I can't add StateIcon objects outside the constructor because my reference to the JPanel (FsaPanel) is wrong somehow. I thought the pan=this; statement would make the global variable equal the FsaPanel.

Everything here compiles, however the StateIcon object is not visible.

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

public class FsaPanel extends JPanel implements FsaListener
{
	private FsaPanel pan;
	
	//constructor
	public FsaPanel()
	{	
		pan=this;
		this.setSize(500,500);
		this.setLayout(null);
	}

	public void statesChanged()
	{
	        StateIcon icon=new StateIcon();
		icon.setLocation(10,10);
		pan.add(icon);
	}
	
	public class StateIcon extends JComponent implements StateListener
	{
		private Ellipse2D.Double circle;
		public StateIcon(State s)
		{
			circle =new Ellipse2D.Double(0,0,80, 80);	
			this.setSize(100,100); 
		}
		
		protected void paintComponent(Graphics g)
		{
			super.paintComponent(g);
			Graphics2D g2d=(Graphics2D)g;
			g2d.setColor(Color.blue);
			g2d.fill(circle);
			
		}
	}	
}

[CasiOo]

I don't believe you when you say it compiles. Here is why

The constructor

public StateIcon(State s)

How you initialize it

StateIcon icon=new StateIcon();

Where is the missing State object parameter?

[tanny_]

CasiOo, on 02 November 2012 - 04:09 PM, said:

I don't believe you when you say it compiles. Here is why

The constructor

public StateIcon(State s)

How you initialize it

StateIcon icon=new StateIcon();

Where is the missing State object parameter?

SORRY! this is part of a larger FSA implementation, I removed fsa specifics to simplify it for the point of this post. (Obviously not thoroughly enough sorry my fault!)Here is my full code.

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

public class FsaPanel extends JPanel implements FsaListener
{
	private Set <State> panelStates=new HashSet<State>();
	private Fsa f;
	private FsaPanel pan;
	
	//constructor
	public FsaPanel(Fsa f)
	{	
		pan=this;
		f.addListener(this);
		this.f=f;
		this.setSize(500,500);
		this.setLayout(null);
	}

	public void statesChanged()
	{
		System.out.println("States Changed");
		if(panelStates.size()<f.getStates().size())
		{
			System.out.println("added state");
			Set<State> temp = new HashSet();
			temp.addAll(f.getStates());
			temp.removeAll(panelStates);
			Iterator tempIT=temp.iterator();
			State s=null;
			while(tempIT.hasNext()){
				s=(State)tempIT.next();
			}
			
			StateIcon icon=new StateIcon(s);
			int x=s.getXpos();
			int y=s.getYpos();
			icon.setLocation(x,y);
			pan.add(icon);
			s.addListener(icon);
			panelStates.addAll(f.getStates());
			//added-> look in f.getStates to see whats new
		}
		else if(panelStates.size()>f.getStates().size())
		{
			//deleted
		}
	}
	
	public void transitionsChanged()
	{
		System.out.println("Transitions Changed");
	}
	
	public void otherChanged()
	{
		System.out.println("Other change");
	}
	
	public class StateIcon extends JComponent implements StateListener
	{
		State s;
		private Ellipse2D.Double circle;
		public StateIcon(State s)
		{
			this.s=s;
			circle =new Ellipse2D.Double(0,0,80, 80);	
			this.setSize(100,100); 
		}
		public void StateHasChanged()
		{	
			System.out.println("State has changed");
		}
		
		protected void paintComponent(Graphics g)
		{
			super.paintComponent(g);
			Graphics2D g2d=(Graphics2D)g;
			g2d.setColor(Color.blue);
			g2d.fill(circle);
			
		}
	}
	
}

[CasiOo]

Don't do the follow, just use the keyword 'this' instead

pan=this;

You will have to invalidate and maybe even repaint after you have added a new component to your container, before it will not show

Try and resize your frame, and see if the new component shows. A resize will normally make the JPanel invalidate itself

[tanny_]

CasiOo, on 02 November 2012 - 04:25 PM, said:

You will have to invalidate and maybe even repaint after you have added a new component to your container, before it will not show

Try and resize your frame, and see if the new component shows. A resize will normally make the JPanel invalidate itself

Yes that's it! I didn't realise you had to repaint, for some reason I thought it did it automatically. Just to clarify, every time you add something to the FsaPanel or make a change, you must call repaint() to make it display? is this all you need to call?

[CasiOo]

tanny_, on 02 November 2012 - 11:42 PM, said:

CasiOo, on 02 November 2012 - 04:25 PM, said:

You will have to invalidate and maybe even repaint after you have added a new component to your container, before it will not show

Try and resize your frame, and see if the new component shows. A resize will normally make the JPanel invalidate itself

Yes that's it! I didn't realise you had to repaint, for some reason I thought it did it automatically. Just to clarify, every time you add something to the FsaPanel or make a change, you must call repaint() to make it display? is this all you need to call?

It depends on the situation
invalidate() and validate() on the container are sometimes necessary

[pbl]

Never a good idea to add component to a container on the fly that can screw up a few layout quite fast
Add all components to the container at construction time. Set their visibility to false if required and toggle them to true later on if required