Thread: When I add a 2nd panel the result is all white

import javax.swing.*;
import java.awt.*;
 
public class PRJ04 extends JFrame
{
    public static void main (String [] args)
    {
        PRJ04 frmApp = new PRJ04();
        PanelChart pnlChart = new PanelChart();
        PanelPopulationInputs pnlInputs = new PanelPopulationInputs();
 
        pnlInputs.setPnlChart(pnlChart);
 
        frmApp.add(pnlInputs, BorderLayout.WEST);
        frmApp.add(pnlChart, BorderLayout.EAST);
 
        frmApp.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frmApp.setSize(600,500);
        frmApp.setVisible(true);
    }
}

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
/**
 * Created by malon_000 on 5/11/14.
 */
public class PanelPopulationInputs extends JPanel implements ActionListener
{
    private JLabel lblBoston;
    private JLabel lblMiami;
    private JLabel lblDallas;
    private JLabel lblStLouis;
    private JLabel lblKansasCity;
    private JLabel lblLosAngeles;
    private JLabel lblSeattle;
 
    private JTextField txtBoston;
    private JTextField txtMiami;
    private JTextField txtDallas;
    private JTextField txtStLouis;
    private JTextField txtKansasCity;
    private JTextField txtLosAngeles;
    private JTextField txtSeattle;
 
    private JButton btnChart;
 
    private PanelChart pnlChart;
 
    public void setPnlChart(PanelChart p)
    {
        pnlChart = p;
    }
 
    public PanelPopulationInputs()
    {
        lblBoston = new JLabel("Boston:");
        lblMiami = new JLabel("Miami:");
        lblDallas = new JLabel("Dallas:");
        lblStLouis = new JLabel("St Louis:");
        lblKansasCity = new JLabel("Kansas City:");
        lblLosAngeles = new JLabel("Los Angeles:");
        lblSeattle = new JLabel("Seattle:");
 
        txtBoston = new JTextField(7);
        txtMiami = new JTextField(7);
        txtDallas = new JTextField(7);
        txtStLouis = new JTextField(7);
        txtKansasCity = new JTextField(7);
        txtLosAngeles = new JTextField(7);
        txtSeattle = new JTextField(7);
 
        btnChart = new JButton("Chart");
        btnChart.setActionCommand("chart");
        btnChart.addActionListener(this);
 
        setLayout(new GridLayout(8,2));
        add(lblBoston);
        add(txtBoston);
        add(lblMiami);
        add(txtMiami);
        add(lblDallas);
        add(txtDallas);
        add(lblStLouis);
        add(txtStLouis);
        add(lblKansasCity);
        add(txtKansasCity);
        add(lblLosAngeles);
        add(txtLosAngeles);
        add(lblSeattle);
        add(txtSeattle);
        add(btnChart);
    }
 
 
    @Override
    public void actionPerformed(ActionEvent e)
    {
        if(e.getActionCommand().equals("chart"))
        {
            pnlChart.setPopulations(Integer.parseInt(txtBoston.getText()),
                    Integer.parseInt(txtMiami.getText()),
                    Integer.parseInt(txtDallas.getText()),
                    Integer.parseInt(txtStLouis.getText()),
                    Integer.parseInt(txtKansasCity.getText()),
                    Integer.parseInt(txtLosAngeles.getText()),
                    Integer.parseInt(txtSeattle.getText()));
        }
 
    }
}

import javax.swing.*;
import java.awt.*;
 
/**
 * Created by malon_000 on 5/11/14.
 */
public class PanelChart extends JPanel
{
    private double boston;
    private double miami;
    private double dallas;
    private double stLouis;
    private double kansasCity;
    private double losAngeles;
    private double seattle;
    private double total;
 
    private Graphics g;
 
    public void paintComponent (Graphics g)
    {
        super.paintComponent(g);
        this.g = g;
        drawChart();
    }
 
    public void setPopulations( int boston, int miami, int dallas, int stLouis,
                                int kansasCity, int losAngeles, int seattle)
    {
        this.boston = boston;
        this.miami = miami;
        this.dallas = dallas;
        this.stLouis = stLouis;
        this.kansasCity = kansasCity;
        this.losAngeles = losAngeles;
        this.seattle = seattle;
 
        total = this.boston + this.miami + this.dallas + this.stLouis + this.kansasCity + this.losAngeles + this.seattle;
 
        repaint();
    }
 
    public void drawChart()
    {
        int pctBoston = (int) (boston/total*36000);
        int pctMiami = (int) (miami/total*36000);
        int pctDallas = (int) (dallas/total*36000);
        int pctStLouis = (int) (stLouis/total*36000);
        int pctKansasCity = (int) (kansasCity/total*36000);
        int pctLosAngeles = (int) (losAngeles/total*36000);
        int pctSeattle = (int) (seattle/total*36000);
 
        int angle = 0;
 
        g.setColor(Color.magenta);
        g.fillArc(10, 10, 50, 50, angle, pctBoston);
 
        angle += pctBoston;
 
        g.setColor(Color.yellow);
        g.fillArc(10, 10, 50, 50, angle, pctMiami);
 
        angle += pctMiami;
 
        g.setColor(Color.gray);
        g.fillArc(10, 10, 50, 50, angle, pctDallas);
 
        angle += pctDallas;
 
        g.setColor(Color.green);
        g.fillArc(10, 10, 50, 50, angle, pctStLouis);
 
        angle += pctStLouis;
 
        g.setColor(Color.red);
        g.fillArc(10, 10, 50, 50, angle, pctKansasCity);
 
        angle += pctKansasCity;
 
        g.setColor(Color.pink);
        g.fillArc(10, 10, 50, 50, angle, pctLosAngeles);
 
        angle += pctLosAngeles;
 
        g.setColor(Color.blue);
        g.fillArc(10, 10, 50, 50, angle, pctSeattle);
    }
 
}

When I comment out the adding and setting of the pnlChart on my main driver, the pnlPopulationInputs shows up fine, and it runs ok. When I add the pnlChart I get errors like crazy and a white screen. My errors:

Exception in thread "AWT-EventQueue-0" java.lang.ArithmeticException: / by zero
at PanelChart.drawChart(PanelChart.java:45)
at PanelChart.paintComponent(PanelChart.java:24)
at javax.swing.JComponent.paint(JComponent.java:1054)
at javax.swing.JComponent.paintChildren(JComponent.ja va:887)
at javax.swing.JComponent.paint(JComponent.java:1063)
at javax.swing.JComponent.paintChildren(JComponent.ja va:887)
at javax.swing.JComponent.paint(JComponent.java:1063)
at javax.swing.JLayeredPane.paint(JLayeredPane.java:5 85)
at javax.swing.JComponent.paintChildren(JComponent.ja va:887)
at javax.swing.JComponent.paintToOffscreen(JComponent .java:5226)
at javax.swing.RepaintManager$PaintManager.paintDoubl eBuffered(RepaintManager.java:1529)
at javax.swing.RepaintManager$PaintManager.paint(Repa intManager.java:1452)
at javax.swing.RepaintManager.paint(RepaintManager.ja va:1249)
at javax.swing.JComponent.paint(JComponent.java:1040)
at java.awt.GraphicsCallback$PaintCallback.run(Graphi csCallback.java:39)
at sun.awt.SunGraphicsCallback.runOneComponent(SunGra phicsCallback.java:78)
at sun.awt.SunGraphicsCallback.runComponents(SunGraph icsCallback.java:115)
at java.awt.Container.paint(Container.java:1967)
at java.awt.Window.paint(Window.java:3877)
at javax.swing.RepaintManager$3.run(RepaintManager.ja va:819)
at javax.swing.RepaintManager$3.run(RepaintManager.ja va:796)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(ProtectionDomain.java:76)
at javax.swing.RepaintManager.paintDirtyRegions(Repai ntManager.java:796)
at javax.swing.RepaintManager.paintDirtyRegions(Repai ntManager.java:769)
at javax.swing.RepaintManager.prePaintDirtyRegions(Re paintManager.java:718)
at javax.swing.RepaintManager.access$1100(RepaintMana ger.java:62)
at javax.swing.RepaintManager$ProcessingRunnable.run( RepaintManager.java:1677)
at java.awt.event.InvocationEvent.dispatch(Invocation Event.java:251)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.j ava:733)
at java.awt.EventQueue.access$200(EventQueue.java:103 )
at java.awt.EventQueue$3.run(EventQueue.java:694)
at java.awt.EventQueue$3.run(EventQueue.java:692)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 703)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(E ventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:91)

Once more with this one, I refer back to our in class example. Our programs are set up the same, yet he has no issues with the "/ by zero" exception.

Exception in thread "AWT-EventQueue-0" java.lang.ArithmeticException: / by zero
at PanelChart.drawChart(PanelChart.java:45)

Look at line 45 and find the divisor with the 0 value. Then backtrack in the code to see why the value is 0.

Is the paintComponent() method called BEFORE the setPopulations() method?

not showing up the second panel

What is the variable name for the "second panel"?

Try debugging the code by adding a println() statement in that class's paintComponent() method that prints out the bounds of the component: the getBounds() method returns the value to print. The print out will show you the size and location of the panel.

I need to get past the x value on my fillArc method?

I'm not sure what you are saying. What does "get past x value" mean?

Did you see this: width=10,
That's not very wide.

EAST is too small. Try CENTER