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Thread: Problems getting Graph to show
- 07-30-2007, 10:59 PM #1
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Problems getting Graph to show
Hey guys! This is really a great forum and you people are a lot nicer than the Sun guys ;) Anyway...I need some help with this program again. Thought I would post a new question for a new problem. Thanks to hardwired.. I've come a long way with it, but the graph is not showing after calculations are made and amortization is done...when the user clicks on Show Graph, the new window pops up but it is blank. Could someone take a look and let me know what you think? Thanks!
Java Code:import java.awt.*; import java.awt.event.*; import java.awt.font.*; import java.awt.geom.*; import java.io.*; import java.text.*; import javax.swing.*; import javax.swing.border.*; import javax.swing.JComboBox; public class MC extends JFrame implements ActionListener { JTextField principalTxt, termTxt, rateTxt, monthlyPaymentTxt; JTextArea displayArea; JButton calculateButton, graphButton, amortizeButton, clearButton, exitButton; JComboBox options; //formatting variables DecimalFormat df = new DecimalFormat("\u00A4#,##0.00"); //currency DecimalFormat pf = new DecimalFormat("#,##0.00%"); //percentages DecimalFormat mi = new DecimalFormat("#,##0.000%"); //percentages // Can these 6 be removed and declared as local variables? int term = 0; double principal = 0; double rate = 0; double monthlyPayment = 0; double interest = 0; int notePeriod = 0; int[] termArray; double[] rateArray; private float[] principalAmts; private float[] interestAmts; public MC() { super ("Mortgage Payment Calculator by S Kemen"); setSize(550, 500); setDefaultCloseOperation(EXIT_ON_CLOSE); load(); setVisible(true); // Initialize components. JPanel row1 = new JPanel(); JLabel mortgageLabel = new JLabel("MORTGAGE PAYMENT CALCULATOR", JLabel.CENTER); JPanel row2 = new JPanel(new GridLayout(1, 2)); JLabel principalLabel = new JLabel("Mortgage Principal $",JLabel.LEFT); principalTxt = new JTextField(10); JPanel row3 = new JPanel(new GridLayout(1, 2)); JLabel termLabel = new JLabel("Mortgage Term (Yrs)",JLabel.LEFT); termTxt = new JTextField(10); JPanel row4 = new JPanel(new GridLayout(1, 2)); JLabel rateLabel = new JLabel("Interest Rate (%)", JLabel.LEFT); rateTxt = new JTextField(10); JPanel row5 = new JPanel(new GridLayout(1, 2)); JLabel presetLabel = new JLabel("Preset Term and Interest Rate:", JLabel.LEFT); JPanel row6 = new JPanel(new GridLayout(1,2)); options = new JComboBox(); MessageFormat mf = new MessageFormat("{0} years at {1,number,#.##}%"); JLabel choiceLabel = new JLabel(" (choose rate)"); for (int i = 0; i < termArray.length; i++) { options.addItem(mf.format(new Object[] { new Integer(termArray [i]), new Double(rateArray[i])})); } JPanel row7 = new JPanel(new GridLayout(1, 2)); JLabel monthlyPaymentLabel = new JLabel("Monthly Payment $", JLabel.LEFT); monthlyPaymentTxt = new JTextField(10); //create buttons JPanel button = new JPanel(new FlowLayout(FlowLayout.CENTER, 10, 10)); graphButton = new JButton("Display Graph"); amortizeButton = new JButton("Amortize Payments"); clearButton = new JButton("Clear"); exitButton = new JButton("Exit"); calculateButton = new JButton("Calculate"); //create textarea to display Amortize output displayArea = new JTextArea(10, 45); JScrollPane scroll = new JScrollPane(displayArea); Container pane = getContentPane(); // Set layout before adding components. pane.setLayout(new BoxLayout( pane, BoxLayout.Y_AXIS)); Border rowborder = new EmptyBorder( 3, 10, 3, 10 ); pane.add(row1); row1.add(mortgageLabel); row1.setMaximumSize( new Dimension( 10000, row1.getMinimumSize().height)); row1.setBorder( rowborder); pane.add(row2); row2.add(principalLabel); row2.add(principalTxt); row2.setMaximumSize( new Dimension( 10000, row2.getMinimumSize().height)); row2.setBorder( rowborder); pane.add(row3); row3.add(termLabel); row3.add(termTxt); row3.setMaximumSize( new Dimension( 10000, row3.getMinimumSize().height)); row3.setBorder( rowborder); pane.add(row4); row4.add(rateLabel); row4.add(rateTxt); row4.setMaximumSize( new Dimension( 10000, row4.getMinimumSize().height)); row4.setBorder( rowborder); pane.add(row5); row5.add(presetLabel); row5.setMaximumSize( new Dimension( 10000, row4.getMinimumSize().height)); row5.setBorder( rowborder); pane.add(row6); row6.add(choiceLabel); row6.setMaximumSize( new Dimension( 10000, row4.getMinimumSize().height)); row6.setBorder( rowborder); JPanel radioPanel = new JPanel(); radioPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 4, 4 )); radioPanel.add(options); pane.add(radioPanel); radioPanel.setMaximumSize( new Dimension( 10000, radioPanel.getMinimumSize().height)); radioPanel.setBorder( rowborder); pane.add(row7); row7.add(monthlyPaymentLabel); row7.add(monthlyPaymentTxt); monthlyPaymentTxt.setEnabled(false); //set payment amount uneditable monthlyPaymentTxt.setFocusable(false); row7.setMaximumSize( new Dimension( 10000, row5.getMinimumSize().height)); row7.setBorder( rowborder); //Add buttons button.add(calculateButton); button.add(clearButton); button.add(exitButton); button.add(amortizeButton); button.add(graphButton); pane.add(button); button.setMaximumSize( new Dimension( 10000, button.getMinimumSize().height)); //scroll text pane for Amortize output scroll.setBorder(BorderFactory.createEmptyBorder(10,10,10,10)); pane.add(scroll); setContentPane(pane); //add listeners for buttons and combo box options.addActionListener(this); clearButton.addActionListener(this); exitButton.addActionListener(this); calculateButton.addActionListener(this); amortizeButton.addActionListener(this); graphButton.addActionListener(this); } public void actionPerformed(ActionEvent event) { Object command = event.getSource(); if(command == calculateButton) { //function for Calculate button try { principal = Double.parseDouble(principalTxt.getText()); } catch(NumberFormatException e) { //catch null pointer exception if Principal is null JOptionPane.showMessageDialog(null, "Invaild Entry! Please Try Again", "ERROR", JOptionPane.ERROR_MESSAGE); } try { //Get input from Term text box, checked first before combo box term = Integer.parseInt(termTxt.getText()); rate = Double.parseDouble(rateTxt.getText()); //Input from Rate text box } catch(NumberFormatException e) { //If Term and Rate are null, buttons are checked for input values //Set rate and term based on which item in the combobox is selected //If no option is selected and combo box null, // this is an actual error. JOptionPane.showMessageDialog(null, "Invaild Entry! " + "Please Try Again", "ERROR", JOptionPane.ERROR_MESSAGE); } interest = rate / 100 / 12; //Monthly interst rate notePeriod = term * 12; //Number of months over which loan is amortized //calculation formula monthlyPayment = (principal * interest) / (1 - Math.pow(1 + interest, -notePeriod)); monthlyPaymentTxt.setText("" + df.format(monthlyPayment)); } if(command == clearButton) { //Function for Clear button principalTxt.setText(""); monthlyPaymentTxt.setText(""); rateTxt.setText(""); termTxt.setText(""); displayArea.setText(""); } if(command == exitButton) { //Function for Exit button System.exit(0); } if (command == amortizeButton) { //Function for Amortize button //Amoritization variables double loanBalance = notePeriod * monthlyPayment; // You need to use the member variables with these two names // so you can send them to your GraphPanel. Instantiate them // here and fill the elements in this loop. The member // variables remain null and choke up GraphPanel. double interestPaid = 0; //Interest paid on the loan double monthlyPrincipal = 0; //Principal in each monthly payment //running total of principal after payment double principalBalance = principal; //String for output String titles = "Month\t Principal\t\tInterest\t\tBalance\n"; displayArea.setText(titles); displayArea.append(""); //Inserts a blank line interestAmts = new float[term*12]; principalAmts = new float[term*12]; //This loop is used to calculate and display the payment schedule information for(int counter = 0; counter < term * 12 - 0; counter++) { //start outer loop //start inner loop interestPaid = principalBalance * interest; interestAmts[counter] = (float)interestPaid; monthlyPrincipal = monthlyPayment - interestPaid; principalAmts[counter] = (float)monthlyPrincipal; loanBalance = loanBalance - monthlyPayment; principalBalance = principalBalance - monthlyPrincipal; //formatting for output displayArea.setCaretPosition(0); displayArea.append((counter +1) + ")\t" + df.format(monthlyPrincipal)+"\t\t" + df.format(interestPaid)+"\t\t" + df.format(principalBalance)+"\n"); } } if (command == graphButton) { //Function for Graph button JDialog d = new JDialog(this, false); d.getContentPane().add(new GraphPanel(principalAmts, interestAmts)); d.setSize(800,600); d.setLocation(200,100); d.setVisible(true); } } //reading from sequential file private void load() { Reader fis; try { fis = new InputStreamReader(getClass().getResourceAsStream("data.txt")); BufferedReader br = new BufferedReader( fis ); termArray = new int[4]; rateArray = new double[4]; String line; int i = 0; while((line = br.readLine()) != null) { String[] s = line.split(","); termArray[ i ] = Integer.parseInt(s[0].trim()); rateArray[ i ] = Double.parseDouble(s[1].trim()); i++; } br.close(); } catch ( Exception e1 ) { e1.printStackTrace( ); } } class GraphPanel extends JPanel { final int HPAD = 60, VPAD = 40; int[] data; Font font; float[] principalAmts; float[] interestAmts; public GraphPanel(float[] principalAmts, float[] interestAmts) { font = new Font("lucida sans regular", Font.PLAIN, 16); setBackground(Color.white); } protected void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D)g; g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2.setFont(font); FontRenderContext frc = g2.getFontRenderContext(); int w = getWidth(); int h = getHeight(); // scales float xInc = (w - HPAD - VPAD) / (interestAmts.length - 1);//11f; //distance between each point float yInc = (h - 2*VPAD) / 10f; int[] dataVals = getDataVals(); //min and max values for y-axis float yScale = dataVals[2] / 10f; // ordinate (y - axis) g2.draw(new Line2D.Double(HPAD, VPAD, HPAD, h - VPAD)); // plot tic marks float x1 = HPAD, y1 = VPAD, x2 = HPAD - 3, y2; for(int j = 0; j < 10; j++) { g2.draw(new Line2D.Double(x1, y1, x2, y1)); y1 += yInc; } // labels String text; LineMetrics lm; float xs, ys, textWidth, height; for(int j = 0; j <= 10; j++) { text = String.valueOf(dataVals[1] - (int)(j * yScale)); textWidth = (float)font.getStringBounds(text, frc).getWidth(); lm = font.getLineMetrics(text, frc); height = lm.getAscent(); xs = HPAD - textWidth - 7; ys = VPAD + (j * yInc) + height/2; g2.drawString(text, xs, ys); if(j == 0) g2.drawString("Principal", xs, ys - 15); } // abcissa (x - axis) g2.draw(new Line2D.Double(HPAD, h - VPAD, w - VPAD, h - VPAD)); // tic marks x1 = HPAD; y1 = h - VPAD; y2 = y1 + 3; for(int j = 0; j < interestAmts.length; j++) { g2.draw(new Line2D.Double(x1, y1, x1, y2)); x1 += xInc; } // labels ys = h - VPAD; for(int j = 0; j < interestAmts.length; j++) { text = String.valueOf(j + 1); textWidth = (float)font.getStringBounds(text, frc).getWidth(); lm = font.getLineMetrics(text, frc); height = lm.getHeight(); xs = HPAD + j * xInc - textWidth/2; g2.drawString(text, xs, ys + height); if( j == (interestAmts.length - 1)) g2.drawString("Year", (int)w /2 , ys + height + 15); } // plot data float yy2 = 0, yy1 = 0, xx2 = 0, xx1; x1 = HPAD; xx1 = HPAD; yScale = (float)(h - 2*VPAD) / dataVals[2]; for(int j = 0; j < interestAmts.length; j++) { g.setColor(Color.blue); y1 = VPAD + (h - 2*VPAD) - (principalAmts[j] - dataVals[0]) * yScale; g2.fillOval((int)x1, (int)y1 - 2, 5, 5); if(j > 0) g2.draw(new Line2D.Double(x1, y1, x2, y2)); x2 = x1; y2 = y1; x1 += xInc; g.setColor(Color.red); yy1 = VPAD + (h - 2*VPAD) - (interestAmts[j] - dataVals[0]) * yScale; g2.fillOval((int)xx1, (int)yy1 - 1, 5, 5); if(j > 0) g2.draw(new Line2D.Double(xx1, yy1, xx2, yy2)); xx2 = xx1; yy2 = yy1; xx1 += xInc; } } private int[] getDataVals() { int max = Integer.MIN_VALUE; int min = Integer.MAX_VALUE; int j = interestAmts.length -1; max = (int)principalAmts[j]; min = (int)interestAmts[j]; int span = max - min; return new int[] { min, max, span }; } } public static void main(String[] args) { MC smc = new MC(); } }
7,5.35
15,5.5
20,5.65
30,5.75
- 07-31-2007, 01:57 AM #2
The first thing I notice in looking at your GraphPanel class is that you did not assign the member variables (principalData, interestData) to the local variables (p, i) in the constructor. This leaves the member variables with the value of null and, when running the class liks this results in this exception in the console:
Java Code:C:\jexp>java MC Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at GraphPanel.paintComponent(mc.java:311)
Java Code:public GraphPanel(float[] p, float[] i) { principalData = p; interestData = i; font = new Font("lucida sans regular", Font.PLAIN, 16); setBackground(Color.white); }
About your last thread:
When I posted a recommendation to change setEnabled to setFocusable on the monthlyPaymentTxt I meant that you should replace the first, setEnabled line with the second, setFocusable line. Use one or the other, not both.
Java Code:// Eliminate/remove this next line. // monthlyPaymentTxt.setEnabled(false); //set payment amount uneditable // Leave this line in. monthlyPaymentTxt.setFocusable(false);
Java Code:// You need to use the member variables with these two names // so you can send them to your GraphPanel. Instantiate them // here and fill the elements in this loop. The member // variables remain null and choke up GraphPanel.
- 07-31-2007, 02:59 AM #3
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Hi again hardwired :) ... So if I'm understanding you correctly, the graph code should look like the following? Because it was like this before and I thought it wouldn't work for some reason and changed a lot of variables. I thought they had to be principalAmts, interestAmts.
Java Code://creates class for graphpanel class GraphPanel extends JPanel { final int HPAD = 60, VPAD = 40; int[] data; Font font; float[] principleData; float[] interestData; public GraphPanel(float[] p, float[] i) { principleData = p; interestData = i; font = new Font("lucida sans regular", Font.PLAIN, 16); setBackground(Color.white); } protected void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D)g; g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2.setFont(font); FontRenderContext frc = g2.getFontRenderContext(); int w = getWidth(); int h = getHeight(); // scales float xInc = (w - HPAD - VPAD) / (interestData.length - 1);//11f; //distance between each plot float yInc = (h - 2*VPAD) / 10f; int[] dataVals = getDataVals(); //min and max values for y-axis float yScale = dataVals[2] / 10f; // ordinate (y - axis) g2.draw(new Line2D.Double(HPAD, VPAD, HPAD, h - VPAD)); // plot tic marks float x1 = HPAD, y1 = VPAD, x2 = HPAD - 3, y2; for(int j = 0; j < 10; j++) { g2.draw(new Line2D.Double(x1, y1, x2, y1)); y1 += yInc; } // labels String text; LineMetrics lm; float xs, ys, textWidth, height; for(int j = 0; j <= 10; j++) { text = String.valueOf(dataVals[1] - (int)(j * yScale)); textWidth = (float)font.getStringBounds(text, frc).getWidth(); lm = font.getLineMetrics(text, frc); height = lm.getAscent(); xs = HPAD - textWidth - 7; ys = VPAD + (j * yInc) + height/2; g2.drawString(text, xs, ys); if(j == 0) g2.drawString("Principle", xs, ys - 15); } // abcissa (x - axis) g2.draw(new Line2D.Double(HPAD, h - VPAD, w - VPAD, h - VPAD)); // tic marks x1 = HPAD; y1 = h - VPAD; y2 = y1 + 3; for(int j = 0; j < interestData.length; j++) { g2.draw(new Line2D.Double(x1, y1, x1, y2)); x1 += xInc; } // labels ys = h - VPAD; for(int j = 0; j < interestData.length; j++) { text = String.valueOf(j + 1); textWidth = (float)font.getStringBounds(text, frc).getWidth(); lm = font.getLineMetrics(text, frc); height = lm.getHeight(); xs = HPAD + j * xInc - textWidth/2; g2.drawString(text, xs, ys + height); if( j == (interestData.length - 1)) g2.drawString("Year", (int)w /2 , ys + height + 15); } // plot data float yy2 = 0, yy1 = 0, xx2 = 0, xx1; x1 = HPAD; xx1 = HPAD; yScale = (float)(h - 2*VPAD) / dataVals[2]; for(int j = 0; j < interestData.length; j++) { g.setColor(Color.blue); y1 = VPAD + (h - 2*VPAD) - (principleData[j] - dataVals[0]) * yScale; g2.fillOval((int)x1, (int)y1 - 2, 5, 5); if(j > 0) g2.draw(new Line2D.Double(x1, y1, x2, y2)); x2 = x1; y2 = y1; x1 += xInc; g.setColor(Color.red); yy1 = VPAD + (h - 2*VPAD) - (interestData[j] - dataVals[0]) * yScale; g2.fillOval((int)xx1, (int)yy1 - 1, 5, 5); if(j > 0) g2.draw(new Line2D.Double(xx1, yy1, xx2, yy2)); xx2 = xx1; yy2 = yy1; xx1 += xInc; } } private int[] getDataVals() { int max = Integer.MIN_VALUE; int min = Integer.MAX_VALUE; int j = interestData.length -1; max = (int)principleData[j]; min = (int)interestData[j]; int span = max - min; return new int[] { min, max, span }; } } }
One other thing... I wanted the input from the ComboBox to insert into the TextBoxes and then be calculated so I entered the following under ActionEvents:
Java Code:if (command==options){ int index = options.getSelectedIndex(); if (index>=0) { termTxt.setText(termArray[index]); rateTxt.setText(pf.format(rateArray[index])); } }
java:170: setText(java.lang.String) in javax.swing.text.JTextComponent cannot be applied to (int)
termTxt.setText(termArray[index]);
- 07-31-2007, 03:06 AM #4
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Nvm I fixed that last one with:
termTxt.setText(Integer.toString(termArray[index]));
But now... I'm back to a blank UI when it starts. Should I post it all again?
- 07-31-2007, 03:37 AM #5
The next thing to do is check on the data that shows up in GraphPanel with something like this:
Java Code:public GraphPanel(float[] p, float[] i) { principleData = p; interestData = i; System.out.printf("principalData = %s%ninterestData = %s%n", java.util.Arrays.toString(principalData), java.util.Arrays.toString(interestData)); font = new Font("lucida sans regular", Font.PLAIN, 16); setBackground(Color.white); }
Last edited by hardwired; 07-31-2007 at 03:39 AM. Reason: typo in printf
- 07-31-2007, 03:53 AM #6
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I figured out why I was getting the blank screen.. I had 2 copies saved and I was running the wrong one, which didn't have the data.txt file present...which gave the blank when I ran the program. It seems to run great now, just need to adjust one area where when it takes the input from the combobox, it enters it in the textbox as ie. 556.00% instead of 5.56%. But that is minor...working on it now
- 07-31-2007, 05:21 AM #7
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