I need two functions to be calculated from the user and wanted to know how I would use the same input field to display in an dialog box both answers when it is done. I am in the fourth week of my comp sci class and I feel like I have dove into a bit of trouble. We were asked to do this program using the JOptionPane but I wanted to do a little more and created my own.
What I have done so far, the program has compiled correctly in JGrasp and Eclipse but shows this when I run the application.
Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: empty String
at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1842)
at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
at java.lang.Double.parseDouble(Double.java:538)
at Nicolas_Carabajal_Assignment3$CalcButtonListener.actionPerformed(Nicolas_Carabajal_Assignment3.java:57)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6525)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3322)
at java.awt.Component.processEvent(Component.java:6290)
at java.awt.Container.processEvent(Container.java:2234)
at java.awt.Component.dispatchEventImpl(Component.java:4881)
at java.awt.Container.dispatchEventImpl(Container.java:2292)
at java.awt.Component.dispatchEvent(Component.java:4703)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
at java.awt.Container.dispatchEventImpl(Container.java:2278)
at java.awt.Window.dispatchEventImpl(Window.java:2739)
at java.awt.Component.dispatchEvent(Component.java:4703)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:751)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:702)
at java.awt.EventQueue$3.run(EventQueue.java:696)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:724)
at java.awt.EventQueue$4.run(EventQueue.java:722)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:721)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
The Code:
/**
*
*@author ngc5043
*@version 1.0
*/
import javax.swing.*;
import java.awt.event.*;
public class Nicolas_Carabajal_Assignment3 extends JFrame
{
private JPanel panel;
private JLabel messageLabel;
private JTextField ExTextField;
private JButton calcButton;
private final int WINDOW_WIDTH = 310;
private final int WINDOW_HEIGHT = 100;
public static void main(String[] args)
{
Nicolas_Carabajal_Assignment3 main = new Nicolas_Carabajal_Assignment3();
main.buildPanel();
}
public Nicolas_Carabajal_Assignment3()
{
setTitle("Expressions Window");
setSize(WINDOW_WIDTH,WINDOW_HEIGHT);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
buildPanel();
add(panel);
setVisible(true);
}
private void buildPanel()
{
messageLabel = new JLabel("Please Enter a Number");
ExTextField = new JTextField(10);
calcButton = new JButton("Calculate");
calcButton.addActionListener(new CalcButtonListener());
panel = new JPanel();
panel.add(messageLabel);
panel.add(ExTextField);
panel.add(calcButton);
}
private class CalcButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String input;
int num_ent = 0;
double answerOne;
input = ExTextField.getText();
answerOne = Double.parseDouble(input);
answerOne = num_ent * num_ent;
JOptionPane.showMessageDialog(null, "Your Answer Is" + answerOne);
/**
* here i would like to add another function. input*(n+1.0)/2.0
*Getting the same number from the user and calculating this aswell.
*/
}
}
}
You called the buildpanel method twice, Thats why the String was empty, now it turns the string into a double and prints it out:
/**
*
*@author ngc5043
*@version 1.0
*/
import javax.swing.*;
import java.awt.event.*;
public class Nicolas_Carabajal_Assignment3 extends JFrame
{
private JPanel panel;
private JLabel messageLabel;
private JTextField ExTextField;
private JButton calcButton;
private final int WINDOW_WIDTH = 310;
private final int WINDOW_HEIGHT = 100;
public static void main(String[] args)
{
Nicolas_Carabajal_Assignment3 main = new Nicolas_Carabajal_Assignment3();
}
public Nicolas_Carabajal_Assignment3()
{
buildPanel();
setTitle("Expressions Window");
setSize(WINDOW_WIDTH,WINDOW_HEIGHT);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(panel);
setVisible(true);
}
private void buildPanel()
{
messageLabel = new JLabel("Please Enter a Number");
ExTextField = new JTextField(10);
calcButton = new JButton("Calculate");
panel = new JPanel();
panel.add(messageLabel);
panel.add(ExTextField);
panel.add(calcButton);
calcButton.addActionListener(new CalcButtonListener());
}
private class CalcButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String input;
int num_ent = 0;
input = ExTextField.getText();
System.out.println(input);
double answerOne = Double.parseDouble(input);
System.out.println(answerOne);
answerOne = num_ent * num_ent;
JOptionPane.showMessageDialog(null, "Your Answer Is" + answerOne);
/**
* here i would like to add another function. input*(n+1.0)/2.0
*Getting the same number from the user and calculating this aswell.
*/
}
}
}