Drawing Graph and Add to JPanel

[halo3]

Hi. I am coding for a simple Graphic Calculator.
As you can see in the picture (img143.imageshack.us/img143/3800/jpanel.png), a graph is supposed to be shown in that orange box (mainPanel).
Since I had coded a Draw.class, I created an object and add to mainPanel

Draw newGraph=new Draw()
mainPanel.add(newGraph)

However, nothing is shown in mainPanel. What did I get wrong?
Thank you.

[r035198x]

Hard to tell without seeing your code.

[halo3]

Thanks for reply.
My codes for Draw.class

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package DrawPanel;

import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
import javax.swing.JFrame;
/**
 *
 * @author NguyenDuyLong
 */
 public class Draw extends JPanel{
        public double x1,x2;
        public int xCenter;
        public int yCenter;
    public Draw(){
        super();
        setVisible(true);
        setBackground(Color.blue);
        setForeground(Color.red);
    }
    @Override
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        xCenter=(int)1024/2;
        yCenter=700;
        
        //xCenter=(int)Size.getWidth()/2;
        //yCenter=(int)Size.getHeight()/2;
        g.drawLine(0,yCenter,xCenter*2,yCenter);
        g.drawLine(xCenter,0,xCenter,yCenter*2);
        //g.drawOval(500,200,200,500);
    }
}

The picture shows how I coded for Panel:
img98.imageshack.us/img98/8112/panel.png

[r035198x]

If I add your panel to a frame I do see something but only after maximizing frame.
You should consider using sizes relative to the the size of the frame in your drawing.

[halo3]

I have been aware of that. However my main point is that the Panel does not seem to work. Even if I change the value of xCenter and yCenter, Panel does not show anything.

[r035198x]

Perhaps show us how you are displaying it then. Are you adding it to a frame?
I certainly see the blue background and the x-y axis.

[halo3]

Please check this link:
img196.imageshack.us/gal.php?g=95376863.png

I try both mainPanel and mainFrame but they show nothing.
Please tell me what I get wrong.

[r035198x]

Where is your code where you test the panel? That is what I asked for above.


example: here is my test for your panel

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import java.awt.Color;
import java.awt.Graphics;

class Draw extends JPanel {
	public double x1, x2;
	public int xCenter;
	public int yCenter;

	public Draw() {
		super();
		setVisible(true);
		setBackground(Color.blue);
		setForeground(Color.red);
	}

	@Override
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		xCenter = 1024 / 2;
		yCenter = 700;

		// xCenter=(int)Size.getWidth()/2;
		// yCenter=(int)Size.getHeight()/2;
		g.drawLine(0, yCenter, xCenter * 2, yCenter);
		g.drawLine(xCenter, 0, xCenter, yCenter * 2);
		// g.drawOval(500,200,200,500);
	}

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

	public static void initGUI() {
		JFrame f = new JFrame("Frame ");
		f.setSize(300, 300);
		f.add(new Draw());
		f.setVisible(true);
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}
}

Now post your code which you say shows nothing.

[halo3]

Ooops. I think I misunderstand your point. What I mean is that the codes

Draw Graph=new Draw() Panel.add(Graph)

do not show anything in the NetBean project that I am trying to do.

[r035198x]

Yeah but those panels don't display on their own you know.

[halo3]

I add mainPanel.setVisible(true) and mainFrame.setVisible(true) as well, but they still do not work. Otherwise, I do not know what to do.

[r035198x]

Since it seems you are never going to post your code, read the code I posted above and compare it to yours then.
P.S If you are new to Java you should close Netbeans, get Textpad and go through Sun's tutorial testing the codes on Textpad.

[halo3]

I think that I did not make my point clear.
The following is my code to check the "Draw.class"

package desktopapplication2;

import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
/**
 *
 * @author NguyenDuyLong
 */
 public class Draw extends JPanel{
        public double x1,x2;
        public int xCenter;
        public int yCenter;
    public Draw(){
        super();
        setVisible(true);
        setBackground(Color.blue);
        setForeground(Color.red);
    }
    @Override
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        xCenter=(int)200;
        yCenter=300;
        
        //xCenter=(int)Size.getWidth()/2;
        //yCenter=(int)Size.getHeight()/2;
        g.drawLine(0,yCenter,xCenter*2,yCenter);
        g.drawLine(xCenter,0,xCenter,yCenter*2);
        //g.drawOval(500,200,200,500);
    }

	public static void main(String[] args) {
		JFrame f = new JFrame("Frame ");
		f.setSize(300, 300);
		f.add(new Draw());
		f.setVisible(true);
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}

}

It works. I agree with you.

I think I should make my point again: The Draw.class works fine. What troubles me is that when I try to plot such graph on a graphPanel in my application, it does not work. I am not interested in drawing one graph but many graphs. It is kind of Graphic Calculator which user can put in equations, click the button "Graph!" and gets the result on the graphPanel. "Draw.java" runs well but when I create a Draw object and add into graphPanel and hope for a similar result, it does not. So my application would not work.

I hope that you would understand me now. If not, I have nothing else to say. It seems to me that I somehow make you angry. Sorry for that.

[r035198x]

Is there any possibility in us seeing the full runnable code where the Draw object is added onto another panel and then does not work?

[halo3]

Basically, I just add a new JPanel newPanel to mainPanel(created by NetBean automatically). In newPanel, I choose "Customize Code" and include:

Draw newGraph= new Draw();
newPanel.add(newGraph);
newPanel.setVisible(true);

The three java files are here:
mediafire.com/download.php?hj3zjgy3kmz]DesktopApplication1.java
mediafire.com/download.php?v1ozdzvatjz]DesktopApplication1AboutBox.java
mediafire.com/download.php?mmnogzmhywd

[r035198x]

You are going to need frames to display the frames on.
I suggest you read the Swing tutorial.

[gancio]

Basically, I just add a new JPanel newPanel to mainPanel(created by NetBean automatically). In newPanel, I choose "Customize Code" and include:

Draw newGraph= new Draw();
newPanel.add(newGraph);
--here--
newPanel.setVisible(true);

The three java files are here:
mediafire.com/download.php?hj3zjgy3kmz]DesktopApplication1.java
mediafire.com/download.php?v1ozdzvatjz]DesktopApplication1AboutBox.java
mediafire.com/download.php?mmnogzmhywd

try to add pack(); --here--

[Fubarable]

gancio, this advice of yours here while creative, is completely irrelevant to the original poster's problem.