NullPointerException

Well this is my code. Are you referring to when i am converting from a string to a double in the action performed method?

import java.awt.*;

import java.io.*;

import java.awt.event.*;

import java.util.*;

public class Quiz08 extends FrameWithClose implements ActionListener {

LabeltestLabel;

TextField myTextBox;

//TextField txtinfo;

TextField txtAnswer;

ButtongetTextButton;

ButtonG2QtButton;

Button G2PtButton;

Button G2LButton;

ButtonG2GilButton;

ButtonG2FozButton;

ButtonExitButton;

double str;

double gallons = 1;

double liters = 3.785;

int gallon = 1;

int quart = 4;

int pint = 8;

int gill = 32;

int fluid = 128;

public static void main(String args [])

{

Quiz08 tf = new Quiz08();

tf.setSize(400,400);

tf.setVisible(true);

}

public Quiz08 (){

setLayout(new FlowLayout());

setBackground(Color.blue);

testLabel = new Label(" a simple test of a TEXT box ");

add(testLabel);

getTextButton= new Button ("get the text");

add(getTextButton);

getTextButton.addActionListener(this);

myTextBox = new TextField();

myTextBox.setText("12 24 15 76 54 15");

txtAnswer = new TextField();

txtAnswer.setText("");

Panel p1 = new Panel();

p1.setLayout(new FlowLayout());

add("Center",p1);

Panel p2 = new Panel();//G2GQt, G2Pt,G2Gil,G2Foz buttons

p2.setLayout(new GridLayout(2,0));

p2.add(G2QtButton);

p2.add(G2PtButton);

p2.add(G2GilButton);

p2.add(G2FozButton);

add("West", p2);

G2QtButton.addActionListener(this);

G2PtButton.addActionListener(this);

G2GilButton.addActionListener(this);

G2FozButton.addActionListener(this);

Panel p3 = new Panel();//G2L and Exit Button

p3.setLayout(new GridLayout(2,0));

p3.add(G2LButton);

p3.add(ExitButton);

add("East", p3);

G2LButton.addActionListener(this);

ExitButton.addActionListener(this);

Panel p4 = new Panel();

p4.setLayout(new FlowLayout());

p4.add(txtAnswer);

add("South",p4);

Panel p5 = new Panel();

p5.setLayout(new FlowLayout());

p5.add(myTextBox);

add("North", p5);

} // end constructor

public void actionPerformed(ActionEvent evt) {

try {

String t = myTextBox.getText();

Double ts = new Double(t);

str = ts.doubleValue();

}

catch (NumberFormatException e) {

txtAnswer.setText("invalid number entered.");

return; // Break out of the actionPerformed method.

}

String s = evt.getActionCommand();

if (evt.getSource() instanceof Button) {

if (s.equals("ExitButton")){

dispose();

System.exit(0);

}

if (s.equals("G2Qt")){

quart = quart%gallon;

txtAnswer.getText();

}

if (s.equals("G2Pt")){

pint = pint%gallon;

txtAnswer.getText();

//ts = pint;

//txtAnswer.setText(pint);

//String t = G2PtButton;

}

if (s.equals("G2Gil")){

gill = gill%gallon;

txtAnswer.getText();

//ts = pint;

//txtAnswer.setText(pint);

//String t = G2GilButton;

}

if (s.equals("G2Foz")){

fluid = fluid%gallon;

txtAnswer.getText();

//ts = fluid;

//txtAnswer.setText(pint);

//String t = G2FozButton;

}

if (s.equals("G2L")){

liters = gallons%liters;

txtAnswer.getText();

// ts = liters;

//String t = G2LButton;

}

} // end instanceof Button

//txtAnswer = ts;

} // end actionEvent

} // end class

wash_ema at 2007-7-8 0:59:17 >

> Well this is my code. Are you referring to when i am

> converting from a string to a double in the action

> performed method?

If you look at the error message, it should tell you in which method and in which line the null pointer exception occurs.

It looks to me like the G2xxx Buttons are never set using "new Button()"

atmguya at 2007-7-8 0:59:17 >