Hiya, I am using following Java file which creates a GUI, in the input field if i put any character why dont I see the JOptionPane.showMessageDialog pop up window as mentioned in the code?

Any clues?

Thx
Rony


//import statements
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

import java.text.DecimalFormat;



/**
* Sediment Yield MUSLE
* Shahriar Shams
* class description
*/
public class SedimentYield1 extends JFrame implements ActionListener
{

double V, Qp, K, LS, C, P;
String outputSY;
boolean goodInput = true;
double SY;

JPanel SYPanelInput = new JPanel();
JPanel SYPanelCentre = new JPanel();
JPanel SYPanelOutput = new JPanel();

private JButton jbtCalculate = new JButton ("Calculate");
private JButton jbtClear = new JButton ("Clear");


//Input

JLabel Vlbl = new JLabel("Volume of Runoff in acre-ft, V");
JTextField Vtf = new JTextField(8);

JLabel Qplbl = new JLabel("Peak Flow per Storm Event in cfs, Qp");
JTextField Qptf = new JTextField(8);

JLabel Klbl = new JLabel("Soil Erodibility Factor, K");
JTextField Ktf = new JTextField(8);

JLabel LSlbl = new JLabel("Soil Loss Ratio, LS");
JTextField LStf = new JTextField(8);

JLabel Clbl = new JLabel("Cropping Factor, C");
JTextField Ctf = new JTextField(8);

JLabel Plbl = new JLabel("Practice Factor, P");
JTextField Ptf = new JTextField(8);



//ouput
JLabel SYlbl = new JLabel("Sediment Yield per storm in tons");
JTextField SYtf = new JTextField("Will be computed");


public SedimentYield1()

{



SYPanelInput.setLayout(new GridLayout(6,2));
SYPanelInput.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
SYPanelCentre.setLayout(new GridLayout(1,2));
SYPanelCentre.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
SYPanelOutput.setLayout(new GridLayout(1,2));
SYPanelOutput.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));



//adding Components

SYPanelInput.add(Vlbl);
SYPanelInput.add(Vtf);

SYPanelInput.add(Qplbl);
SYPanelInput.add(Qptf);

SYPanelInput.add(Klbl);
SYPanelInput.add(Ktf);

SYPanelInput.add(LSlbl);
SYPanelInput.add(LStf);

SYPanelInput.add(Clbl);
SYPanelInput.add(Ctf);

SYPanelInput.add(Plbl);
SYPanelInput.add(Ptf);

//output added

SYPanelCentre.add(SYlbl);
SYPanelCentre.add(SYtf);



// adding buttons

SYPanelOutput.add(jbtCalculate);
jbtCalculate.addActionListener(this);
SYPanelOutput.add(jbtClear);
jbtClear.addActionListener(this);

String strV = Vtf.getText();
String strQp = Qptf.getText();
String strK = Ktf.getText();
String strLS = LStf.getText();
String strC = Ctf.getText();
String strP = Ptf.getText();


try
{

V = Double.parseDouble(strV);


}

catch (NumberFormatException nfeDouble)
{

JOptionPane.showMessageDialog(null, "You need to enter a\nnumber", "Input Error", JOptionPane.ERROR_MESSAGE);
goodInput = false;

}
try
{


Qp = Double.parseDouble(strQp);


}

catch (NumberFormatException nfeDouble)
{

JOptionPane.showMessageDialog(null, "You need to enter a\nnumber", "Input Error", JOptionPane.ERROR_MESSAGE);
goodInput = false;

}
try
{


K = Double.parseDouble(strK);


}

catch (NumberFormatException nfeDouble)
{

JOptionPane.showMessageDialog(null, "You need to enter a\nnumber", "Input Error", JOptionPane.ERROR_MESSAGE);
goodInput = false;

}
try
{


LS = Double.parseDouble(strLS);

}

catch (NumberFormatException nfeDouble)
{

JOptionPane.showMessageDialog(null, "You need to enter a\nnumber", "Input Error", JOptionPane.ERROR_MESSAGE);
goodInput = false;

}
try
{


C = Double.parseDouble(strC);


}

catch (NumberFormatException nfeDouble)
{

JOptionPane.showMessageDialog(null, "You need to enter a\nnumber", "Input Error", JOptionPane.ERROR_MESSAGE);
goodInput = false;

}
try
{


P = Double.parseDouble(strP);

}

catch (NumberFormatException nfeDouble)
{

JOptionPane.showMessageDialog(null, "You need to enter a\nnumber", "Input Error", JOptionPane.ERROR_MESSAGE);
goodInput = false;

}


if (goodInput)
{

//Calculating Sediment Yield
SY = 95.0*(Math.pow((V*Qp),0.56))*K*LS*C*P;

//Create the format for the Celsius text field.
DecimalFormat twoDigits = new DecimalFormat("0.00");
outputSY = twoDigits.format(SY);


}







// JFrame.setDefaultLookAndFeelDecorated(true);

//2. Create the frame.
JFrame frame = new JFrame("Sedidement Yield from Watershed");

//3. Optional: What happens when the frame closes?
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

//4. Create components and put them in the frame.
//...create emptyLabel...

frame.getContentPane().add(SYPanelInput, BorderLayout.NORTH);
frame.getContentPane().add(SYPanelCentre, BorderLayout.CENTER);
frame.getContentPane().add(SYPanelOutput, BorderLayout.SOUTH);
//5. Size the frame.
frame.setSize(new Dimension(500,280));
//6. Show it.
frame.setVisible(true);
}

public static void main(String[] args) {
SedimentYield SYframe = new SedimentYield();

}


public void actionPerformed(ActionEvent e) {


if (e.getSource()== jbtClear)
{

Vtf.setText("");
Qptf.setText("");
Ktf.setText("");
LStf.setText("");
Ctf.setText("");
Ptf.setText("");
SYtf.setText("Will be calculated");

}


if (e.getSource()== jbtCalculate)
{

System.out.println("Sediment Yield ="+outputSY);
SYtf.setText(outputSY);

}


}
}

I'm not going to read a thousand lines of unformated code.
Use code tags and post only the relevant bits.

Most likely you never attached the code that shows the message to the component where you want it shown.

It never throws the exception?

Hi everyone,

It does not pop up because there was no exception thrown as you option pane only shows up if there are exceptions or errors much like your below code


I hope this helps you

Yours Sincerely

Richard West