drawRect()

[Ritchie Partridge]

Hi,
I'm having trouble using the drawRect method. I'm using a JTabbedPane which calls the class FamilyTree which in turn calls the RectanglesCanvas class, not sure what i'm doing wrong.
Thanks.

import javax.swing.JTabbedPane;
import javax.swing.ImageIcon;
import javax.swing.JFrame; 
import java.awt.*; 
import java.awt.event.*;
import javax.swing.*;
public class TabbedPaneDemo extends JApplet
{
public static Color on = new Color(255,204,153);
public static Color off = new Color(51,102,51);
    public TabbedPaneDemo() 
{
UIManager.put("TabbedPane.selected", on);
        JTabbedPane tabbedPane = new JTabbedPane();
getContentPane().setBackground(on);     

        ImageIcon icon = createImageIcon("middle.gif");
PersonalDetails pers = new PersonalDetails();
        JPanel panel1 = pers.makePersonalDetails();
tabbedPane.addTab("Personal Details", icon, panel1,
                          "Allows user to enter personal details");
        tabbedPane.setMnemonicAt(0, KeyEvent.VK_1);
FamilyTree fam = new FamilyTree();
JPanel panel2 =  fam.makeFamilyTree("Panel #2");
        tabbedPane.addTab("Family Tree", icon, panel2,
                          "Gives a graphical representation of the family tree");
       tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);

//DemoRectangle de = new DemoRectangle();
//tabbedPane.add(de,"fdsafd");

    //    tabbedPane.addTab("Rectangles", icon, panel5,
      //                    "Allows user to edit/delete details");
        tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);

EventDetails event = new EventDetails();
JPanel panel3 = event.makeEventDetails("Panel #3");
        tabbedPane.addTab("Events", icon, panel3,
                          "Allows user to enter event details");
        tabbedPane.setMnemonicAt(2, KeyEvent.VK_3);

DeleteDetails delete = new DeleteDetails();
JPanel panel4 = delete.makeDeleteDetails("Panel #4");
        tabbedPane.addTab("Edit/Delete", icon, panel4,
                          "Allows user to edit/delete details");
        tabbedPane.setMnemonicAt(3, KeyEvent.VK_4);
        //Add the tabbed pane to this panel.
        getContentPane().add(tabbedPane);
        
        //Uncomment the following line to use scrolling tabs.
    //    tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);
for(int i=0;i<4;i++)
{
tabbedPane.setForegroundAt(i,off);
tabbedPane.setBackgroundAt(i,on);
}
panel1.setBackground(on); 
//panel2.setBackground(on); 
panel3.setBackground(on); 
panel4.setBackground(on); 
panel1.setForeground(off); 
//panel2.setForeground(off); 
panel3.setForeground(off); 
panel4.setForeground(off);
    }
    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) 
{
        java.net.URL imgURL = TabbedPaneDemo.class.getResource(path);
        if (imgURL != null) 
{
            return new ImageIcon(imgURL);
        } 
else 
{
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() 
{
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);
        //Create and set up the window.
        JFrame frame = new JFrame("Family Tree");
 frame.setBackground(off);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //Create and set up the content pane.
        frame.getContentPane().add(new TabbedPaneDemo(), BorderLayout.CENTER);

        //Display the window.
        frame.pack();
        frame.setSize(600,350);
        frame.setVisible(true);
       
frame.update(frame.getGraphics());
    }
public void actionPerformed(ActionEvent event) 
{
}
    public static void main(String[] args) 
{
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() 
{
            public void run() 
{
                createAndShowGUI();
            }
        });
    }
}
import java.awt.event.*;
import java.awt.Color;
import javax.swing.*;
import javax.swing.JScrollPane; //for scroll bars
import java.awt.BorderLayout;
import java.awt.*;            // for Graphics, Component, Color, Font
import java.awt.Graphics;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import javax.swing.JPanel;
import javax.swing.event.*;
import javax.swing.border.*;
import java.awt.geom.*;
import java.awt.image.*;

class FamilyTree extends JApplet
{
privateJPanel panel2;
Rectangle rect;
protected JPanel makeFamilyTree(String text) 
{
RectanglesCanvas canvas = new RectanglesCanvas();
panel2.add(canvas);
return panel2;
}
public void paintComponent(Graphics g)
{ 
g.setColor(Color.white);
paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.draw(rect);
g2.fill(rect);
}
}
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.*;
public class DemoRectangle extends JApplet {
    RectanglesCanvas canvas;
   
public void init() 
{
  
        Container container = getContentPane();
  
        canvas = new RectanglesCanvas();
        container.add(canvas);
        JPanel panel = new JPanel();
        container.add(BorderLayout.SOUTH, panel);
    }
   
  
    class RectanglesCanvas extends Canvas 
{
        Rectangle2D [] rec1 = new Rectangle2D[5];
      
        RectanglesCanvas() 
{
            // Create instances of 2D rectangles
for (int i=0;i<10 ;i+=2)
{
rec1 [i/2]= new Rectangle2D.Float(25*i, 25*i, 75, 50);
            setBackground(Color.white);
}
     }
        public void paint(Graphics g) 
{    
            Graphics2D g2D = (Graphics2D) g;
                                                      
            g2D.setStroke(new BasicStroke(5.0f));
 for(int i=0;i<5;i++)
            g2D.draw(rec1[i]);
  
        }
    }
}

[Nathan Pruett]

The very first thing I noticed is that RectangleCanvas extends Canvas. This is an AWT component, and you are using Swing components in other places. This causes no end of problems, but is easy to fix. Instead of subclassing Canvas, just subclass JPanel, and change paint(Graphics) to paintComponent(Graphics).

[Ritchie Partridge]

Thanks, but the rectangles still don't seem to be displaying

[Don Kiddick]

public void paintComponent(Graphics g){ 
g.setColor(Color.white);
paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.draw(rect);
g2.fill(rect);
}

The line paintComponent(g); will cause an infinite loop right ? I think you want super.paintComponent( g );
D.

[Ritchie Partridge]

Thanks Don,
But it still doesn't seem to return the panel.

[Don Kiddick]

post your latest code.
D.

[Ritchie Partridge]

I have cut out the middle class FamilyTree just to simplify it

import javax.swing.JTabbedPane;
import javax.swing.ImageIcon;
import javax.swing.JFrame; 
import java.awt.*; 
import java.awt.event.*;
import javax.swing.*;
public class TabbedPaneDemo extends JApplet
{
public static Color on = new Color(255,204,153);
public static Color off = new Color(51,102,51);
    public TabbedPaneDemo() 
{

UIManager.put("TabbedPane.selected", on);
        JTabbedPane tabbedPane = new JTabbedPane();
getContentPane().setBackground(on);     

        ImageIcon icon = createImageIcon("middle.gif");
PersonalDetails pers = new PersonalDetails();
        JPanel panel1 = pers.makePersonalDetails();
tabbedPane.addTab("Personal Details", icon, panel1,
                          "Allows user to enter personal details");
        tabbedPane.setMnemonicAt(0, KeyEvent.VK_1);
/*FamilyTree fam = new FamilyTree();
JPanel panel2 =  fam.makeFamilyTree("Panel #2");
      tabbedPane.addTab("Family Tree", icon, panel2,
                         "Gives a graphical representation of the family tree");
       tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);
*/
DemoRectangle de = new DemoRectangle();
JPanel panel2 = new JPanel();
panel2.add(de);
tabbedPane.addTab("Family Tree", icon, panel2,
                         "Gives a graphical representation of the family tree");
       tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);
//tabbedPane.add(de,"fdsafd");

    //    tabbedPane.addTab("Rectangles", icon, panel5,
      //                    "Allows user to edit/delete details");
    //    tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);

EventDetails event = new EventDetails();
JPanel panel3 = event.makeEventDetails("Panel #3");
        tabbedPane.addTab("Events", icon, panel3,
                          "Allows user to enter event details");
        tabbedPane.setMnemonicAt(2, KeyEvent.VK_3);

DeleteDetails delete = new DeleteDetails();
JPanel panel4 = delete.makeDeleteDetails("Panel #4");
        tabbedPane.addTab("Edit/Delete", icon, panel4,
                          "Allows user to edit/delete details");
        tabbedPane.setMnemonicAt(3, KeyEvent.VK_4);
        //Add the tabbed pane to this panel.
        getContentPane().add(tabbedPane);
        
        //Uncomment the following line to use scrolling tabs.
    //    tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);
for(int i=0;i<4;i++)
{
tabbedPane.setForegroundAt(i,off);
tabbedPane.setBackgroundAt(i,on);
}
panel1.setBackground(on); 
panel2.setBackground(on); 
panel3.setBackground(on); 
panel4.setBackground(on); 
panel1.setForeground(off); 
panel2.setForeground(off); 
panel3.setForeground(off); 
panel4.setForeground(off);
    }
    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) 
{
        java.net.URL imgURL = TabbedPaneDemo.class.getResource(path);
        if (imgURL != null) 
{
            return new ImageIcon(imgURL);
        } 
else 
{
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() 
{
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);
        //Create and set up the window.
        JFrame frame = new JFrame("Family Tree");
 frame.setBackground(off);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //Create and set up the content pane.
        frame.getContentPane().add(new TabbedPaneDemo(), BorderLayout.CENTER);

        //Display the window.
        frame.pack();
        frame.setSize(600,350);
        frame.setVisible(true);
frame.setIconImage(new ImageIcon("middle.gif").getImage()); 
       
frame.update(frame.getGraphics());
    }
public void actionPerformed(ActionEvent event) 
{
}
    public static void main(String[] args) 
{
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() 
{
            public void run() 
{
                createAndShowGUI();
            }
        });
    }
}

import javax.swing.JTabbedPane;
import javax.swing.ImageIcon;
import javax.swing.JFrame; 
import java.awt.*; 
import java.awt.event.*;
import javax.swing.*;
public class TabbedPaneDemo extends JApplet
{
public static Color on = new Color(255,204,153);
public static Color off = new Color(51,102,51);
    public TabbedPaneDemo() 
{

UIManager.put("TabbedPane.selected", on);
        JTabbedPane tabbedPane = new JTabbedPane();
getContentPane().setBackground(on);     

        ImageIcon icon = createImageIcon("middle.gif");
PersonalDetails pers = new PersonalDetails();
        JPanel panel1 = pers.makePersonalDetails();
tabbedPane.addTab("Personal Details", icon, panel1,
                          "Allows user to enter personal details");
        tabbedPane.setMnemonicAt(0, KeyEvent.VK_1);
/*FamilyTree fam = new FamilyTree();
JPanel panel2 =  fam.makeFamilyTree("Panel #2");
      tabbedPane.addTab("Family Tree", icon, panel2,
                         "Gives a graphical representation of the family tree");
       tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);
*/
DemoRectangle de = new DemoRectangle();
JPanel panel2 = new JPanel();
panel2.add(de);
tabbedPane.addTab("Family Tree", icon, panel2,
                         "Gives a graphical representation of the family tree");
       tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);
//tabbedPane.add(de,"fdsafd");

    //    tabbedPane.addTab("Rectangles", icon, panel5,
      //                    "Allows user to edit/delete details");
    //    tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);

EventDetails event = new EventDetails();
JPanel panel3 = event.makeEventDetails("Panel #3");
        tabbedPane.addTab("Events", icon, panel3,
                          "Allows user to enter event details");
        tabbedPane.setMnemonicAt(2, KeyEvent.VK_3);

DeleteDetails delete = new DeleteDetails();
JPanel panel4 = delete.makeDeleteDetails("Panel #4");
        tabbedPane.addTab("Edit/Delete", icon, panel4,
                          "Allows user to edit/delete details");
        tabbedPane.setMnemonicAt(3, KeyEvent.VK_4);
        //Add the tabbed pane to this panel.
        getContentPane().add(tabbedPane);
        
        //Uncomment the following line to use scrolling tabs.
    //    tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);
for(int i=0;i<4;i++)
{
tabbedPane.setForegroundAt(i,off);
tabbedPane.setBackgroundAt(i,on);
}
panel1.setBackground(on); 
panel2.setBackground(on); 
panel3.setBackground(on); 
panel4.setBackground(on); 
panel1.setForeground(off); 
panel2.setForeground(off); 
panel3.setForeground(off); 
panel4.setForeground(off);
    }
    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) 
{
        java.net.URL imgURL = TabbedPaneDemo.class.getResource(path);
        if (imgURL != null) 
{
            return new ImageIcon(imgURL);
        } 
else 
{
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() 
{
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);
        //Create and set up the window.
        JFrame frame = new JFrame("Family Tree");
 frame.setBackground(off);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //Create and set up the content pane.
        frame.getContentPane().add(new TabbedPaneDemo(), BorderLayout.CENTER);

        //Display the window.
        frame.pack();
        frame.setSize(600,350);
        frame.setVisible(true);
frame.setIconImage(new ImageIcon("middle.gif").getImage()); 
       
frame.update(frame.getGraphics());
    }
public void actionPerformed(ActionEvent event) 
{
}
    public static void main(String[] args) 
{
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() 
{
            public void run() 
{
                createAndShowGUI();
            }
        });
    }
}

[Don Kiddick]

The code you posted doesn't appear to call draw() or drawRect() or anything of relevence...

[Ritchie Partridge]

Whoops, posted the same file twice, here there are again:

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.*;
public class DemoRectangle extends JApplet
{
RectanglesCanvas canvas;
Rectangle rect;
   
class RectanglesCanvas extends JPanel
{
Rectangle2D [] rec1 = new Rectangle2D[5];
RectanglesCanvas() 
{
super();
// Create instances of 2D rectangles
for (int i=0;i<10 ;i+=2)
{
rec1 [i/2]= new Rectangle2D.Float(25*i, 25*i, 75, 50);
setBackground(Color.white);
setForeground(Color.black);
}
Container container = getContentPane();
  
canvas = new RectanglesCanvas();
container.add(canvas);
JPanel panel = new JPanel();
container.add(panel);
}
public void paintComponent(Graphics g)
{ 
super.paintComponent(g);
g.setColor(Color.white);

Graphics2D g2 = (Graphics2D)g;
g2.draw(rect);
g2.fill(rect);
}
}
}
import javax.swing.JTabbedPane;
import javax.swing.ImageIcon;
import javax.swing.JFrame; 
import java.awt.*; 
import java.awt.event.*;
import javax.swing.*;
public class TabbedPaneDemo extends JApplet
{
public static Color on = new Color(255,204,153);
public static Color off = new Color(51,102,51);
    public TabbedPaneDemo() 
{

UIManager.put("TabbedPane.selected", on);
        JTabbedPane tabbedPane = new JTabbedPane();
getContentPane().setBackground(on);     

        ImageIcon icon = createImageIcon("middle.gif");
PersonalDetails pers = new PersonalDetails();
        JPanel panel1 = pers.makePersonalDetails();
tabbedPane.addTab("Personal Details", icon, panel1,
                          "Allows user to enter personal details");
        tabbedPane.setMnemonicAt(0, KeyEvent.VK_1);
/*FamilyTree fam = new FamilyTree();
JPanel panel2 =  fam.makeFamilyTree("Panel #2");
      tabbedPane.addTab("Family Tree", icon, panel2,
                         "Gives a graphical representation of the family tree");
       tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);
*/
DemoRectangle de = new DemoRectangle();
JPanel panel2 = new JPanel();
panel2.add(de);
tabbedPane.addTab("Family Tree", icon, panel2,
                         "Gives a graphical representation of the family tree");
       tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);
//tabbedPane.add(de,"fdsafd");

    //    tabbedPane.addTab("Rectangles", icon, panel5,
      //                    "Allows user to edit/delete details");
    //    tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);

EventDetails event = new EventDetails();
JPanel panel3 = event.makeEventDetails("Panel #3");
        tabbedPane.addTab("Events", icon, panel3,
                          "Allows user to enter event details");
        tabbedPane.setMnemonicAt(2, KeyEvent.VK_3);

DeleteDetails delete = new DeleteDetails();
JPanel panel4 = delete.makeDeleteDetails("Panel #4");
        tabbedPane.addTab("Edit/Delete", icon, panel4,
                          "Allows user to edit/delete details");
        tabbedPane.setMnemonicAt(3, KeyEvent.VK_4);
        //Add the tabbed pane to this panel.
        getContentPane().add(tabbedPane);
        
        //Uncomment the following line to use scrolling tabs.
    //    tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);
for(int i=0;i<4;i++)
{
tabbedPane.setForegroundAt(i,off);
tabbedPane.setBackgroundAt(i,on);
}
panel1.setBackground(on); 
panel2.setBackground(on); 
panel3.setBackground(on); 
panel4.setBackground(on); 
panel1.setForeground(off); 
panel2.setForeground(off); 
panel3.setForeground(off); 
panel4.setForeground(off);
    }
    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) 
{
        java.net.URL imgURL = TabbedPaneDemo.class.getResource(path);
        if (imgURL != null) 
{
            return new ImageIcon(imgURL);
        } 
else 
{
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() 
{
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);
        //Create and set up the window.
        JFrame frame = new JFrame("Family Tree");
 frame.setBackground(off);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //Create and set up the content pane.
        frame.getContentPane().add(new TabbedPaneDemo(), BorderLayout.CENTER);

        //Display the window.
        frame.pack();
        frame.setSize(600,350);
        frame.setVisible(true);
frame.setIconImage(new ImageIcon("middle.gif").getImage()); 
       
frame.update(frame.getGraphics());
    }
public void actionPerformed(ActionEvent event) 
{
}
    public static void main(String[] args) 
{
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() 
{
            public void run() 
{
                createAndShowGUI();
            }
        });
    }
}

[Ernest Friedman-Hill]

RectanglesCanvas.paintComponent draws the Rectangle it finds in the member variable "rect" of the enclosing class. But I don't see where this variable is ever initialzed -- i.e., it's null, so there's nothing to draw. Actually, you ought to be getting stack traces because of this.

[Ritchie Partridge]

Sorry meant to use the following:

public void paintComponent(Graphics g)
{ 
super.paintComponent(g);
g.setColor(Color.white);

Graphics2D g2 = (Graphics2D)g;
for (int i=0;i<5 ;i++)
{
g2.draw(rect[i]);
g2.fill(rect[i]);
}
}

Is there a scope problem with this?

[Ernest Friedman-Hill]

So, looking back through this thread, I don't see where you actually told us what the problem is we're trying to solve. Does this compile? Does it run but crash? Does it run but do nothing? Do some tabs work, but not others?
How about if you just stuff the RectanglesApplet into a JFrame, without the JTabbedPane and all the other stuff. Does it show up? What do you see?

[Ritchie Partridge]

It compiles and runs, the other tabs work ok, but this tab is blank. I tried to simplify it too and it still shows up blank. Presume i'm accessing it wrong.

[Ritchie Partridge]

Anyone any ideas?