why i'm not getting graph (output)?

[vishnu vardhan brundavanam]

hi...everyone....
I created an applet which contains a manubar .In that menubar only one manuitem " load file..."(menu item) is there. Which is used to browse the a file which contains a number of values to draw the graph. By that values i want to draw a line graph .
my aim is that when ever i browse a new file , take the values form that and to draw new graph base on the old scale.(if i browsed two files ,then the graph should contain two line graphs ) ...
here is the calling one...

import java.applet.*;
import java.awt.*;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.FileReader;
import javax.swing.*;

public class DrawGraph extends JApplet {
	String sourcefile;

	public DrawGraph() {

	}

	JFrame frame = new JFrame();
	Canvas c;
	ScrollPane s;
	JMenuBar menuBar = new JMenuBar();

	public void init() {
		try {

			JMenuBar myMenu = new JMenuBar();
			JMenu main = new JMenu("File");
			JMenuItem item = new JMenuItem("Load File...");
			item.addActionListener(new MenuImplimentation());
			main.add(item);

			// JMenuItem item2 = new JMenuItem("Draw Graph...");
			// item2.addActionListener(new MenuImplimentation());
			// main.add(item2);
			myMenu.add(main);
			this.setJMenuBar(myMenu);

		} catch (Exception e) {
		}
	}

}

when we browse a file ,then it is reading the file data but,graph was displaying.......
here is the code....

import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.ScrollPane;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.font.FontRenderContext;
import java.awt.font.LineMetrics;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

import javax.swing.JApplet;
import javax.swing.JFileChooser;

public class MenuImplimentation extends Canvas implements ActionListener {
	int a;
	DrawGraph d = new DrawGraph();
	int data[];
	 String sourcefile;
	final int PAD = 30;
	BufferedReader src11 = null;
	BufferedReader src1;
	Graphics g;
	File file;
	int max = -Integer.MAX_VALUE;
	Canvas c;
	ScrollPane s;
	
	public void actionPerformed(ActionEvent ae) {

		
			JFileChooser fc = new JFileChooser();
			// int i = fc.showOpenDialog(this);
			int retval = fc.showOpenDialog(d);
			if (retval == JFileChooser.APPROVE_OPTION) {
				// ... The user selected a file, get it, use it.
				file = fc.getSelectedFile();
				System.out
						.println("the path of the file is :" + file.getPath());
				sourcefile = file.getPath();

				try {
					BufferedReader src1 = new BufferedReader(new FileReader(
							sourcefile));
					String str;
					int i1 = 0, counter = 0;

					while ((str = src1.readLine()) != null) {
						counter++;
					}

					data = new int[counter];

					BufferedReader src11 = new BufferedReader(new FileReader(
							sourcefile));
					try {

						while ((str = src11.readLine()) != null) {

							int a = (int) Integer.parseInt(str.trim());
							data[i1] = a;
							i1++;
							System.out.println(a);
						}

					} catch (NumberFormatException n) {
						n.printStackTrace();
					} catch (IOException e) {

						e.printStackTrace();
					}
					try {
						src11.close();
					} catch (Exception e1) {

						e1.printStackTrace();
					}
			//MyCanvas m =	new MyCanvas(sourcefile);
			//m.getData(); 
			//m.paint(g);
				} catch (IOException e) {

					e.printStackTrace();
				}
			}

			}
			public void init() throws IOException {
			BufferedReader src11 = new BufferedReader(new FileReader(
					sourcefile));

		int counter = 0;

		while ((src11.readLine()) != null) {
		counter++;
		}

		
		s = new ScrollPane();
//	this.add(s);
		c = this;
//			c = new MyCanvas("C:\\data\\data.txt");
		c.setSize((int) (20 * counter) + 30, 600);
		s.add(c);	
	

	}

	public void paint(Graphics g){
	Graphics2D g2 = (Graphics2D) g;
	g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
			RenderingHints.VALUE_ANTIALIAS_ON);

	int w = getWidth();
	int h = getHeight();

	g2.draw(new Line2D.Double(PAD, PAD, PAD, h - PAD));

	g2.draw(new Line2D.Double(PAD, h - PAD, w - PAD, h - PAD));

	Font font = g2.getFont();
	FontRenderContext frc = g2.getFontRenderContext();
	LineMetrics lm = font.getLineMetrics("0", frc);
	float sh = lm.getAscent() + lm.getDescent();

	String s = " data ";
	float sy = PAD + ((h - 2 * PAD) - s.length() * sh) / 2 + lm.getAscent();
	for (int i = 0; i < s.length(); i++) {
		String letter = String.valueOf(s.charAt(i));
		float sw = (float) font.getStringBounds(letter, frc).getWidth();
		float sx = (PAD - sw) / 2;

		g2.drawString(letter, sx, sy);
		sy += sh;
	}

	
	for (int i = 0; i < data.length; i++) {
		if (data[i] > max)
			max = data[i];
	}
	
	double xInc = 20;// (double) (w - 2 * PAD) / (data.length - 1);

	double scale = ((double) (h - 2 * PAD) / max)-1;
	double x1 = 0;
	g2.setPaint(Color.green.darker());
	for (int i = 0; i < data.length - 1; i++) {
		x1 = PAD + i * xInc;
		double y1 = h - PAD - scale * data[i];
		double x2 = PAD + (i + 1) * xInc;
		double y2 = h - PAD - scale * data[i + 1];
		g2.draw(new Line2D.Double(x1, y1, x2, y2));

		g2.drawString((i + 1) + "", (float) x1, h - (PAD - 15));

	}

	g2.setPaint(Color.red);
	for (int i = 0; i < data.length; i++) {
		double x = PAD + i * xInc;
		double y = h - PAD - scale * data[i];
		g2.fill(new Ellipse2D.Double(x - 2, y - 2, 4, 4));
		setPreferredSize(new Dimension(getWidth(), getHeight()));
	}

	sourcefile = null;
	}
	

	}
	

a blank applet with menubar is appearing ....
could you tellme whats wrong with my code ...?
than you ....

[Lester Burnham]

The applet does nothing by itself - what did you expect? If you're performing any UI actions, tell us what those are, what you expected to happen in response, and what actually happened.

By the way, this:

} catch (Exception e) {  
}

is almost never a good idea. At least print a message somewhere that an exception occurred.

[Maneesh Godbole]

After you load the data, you need to tell your canvas to draw the graphs. Invoke a repaint() on it.

Canvas is an AWT component. JApplet is a swing component. You will be better off using JPanel instead of Canvas. In case of Swing components, the recommended way is to override paintComponent() instead of paint()

[vishnu vardhan brundavanam]

In this program my intention is to draw a graph with the help of GUI. Means when i click "load file"menuitem it should tacke a file and should draw a graph with the value which are in that file...
When i'm clicking "Load flie" menuitem,it is tacking file,but not drawing graph....that is my problem....

[Maneesh Godbole]

Maneesh Godbole wrote:After you load the data, you need to tell your canvas to draw the graphs. Invoke a repaint() on it.