For testing purposes I have created a GUI in my ClientGUI class. The program never seems to exit and hangs.I call my create function in main to see how the gui looks and after this the program should terminate but instead it hangs.Please explain to me why this is happening.
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.io.*;
import java.net.*;
public class ClientGUI extends JFrame{
// creates username textfield
private JLabel username = new JLabel("Username ");
private JTextField textUsername = new JTextField(10);
//creates password textfield
private JLabel password = new JLabel("Password ");
private JPasswordField passText = new JPasswordField(10);
// adding two buttons
private JButton Login = new JButton("Login");
private JButton Create = new JButton("Create");
private JPanel error;
private JFrame my_error;
private JLabel errormsg = new JLabel("Error Try Again");
private JButton cancel_me = new JButton("OK");
private String option;
private String usr_name;
private char [] ident;
private String pass;
private String passme;
public volatile boolean []go = new boolean[1];
// constructor
ClientGUI(){
super("GossApp"); //title of jframe
}
public void CreatGui(){
JPanel myPanel = new JPanel(new GridBagLayout()); // creates a panel of type gridbaglayout
GridBagConstraints GridC = new GridBagConstraints();// constraints for layout
GridC.insets = new Insets(0,10,0,10); // spacing
// position 0,0 is corner
GridC.gridx = 0;
GridC.gridy = 0;
myPanel.add(username, GridC); // adding to panel
// position 0,1 adding user text field below username
GridC.gridy = 1;
myPanel.add(textUsername, GridC);
// position 0, 2 adding password name below user
GridC.gridx = 0;
GridC.gridy = 2;
myPanel.add(password, GridC);
//position 0,3 adding password text field below password
GridC.gridy = 3;
myPanel.add(passText, GridC);
// adding login button to panel next to password text
GridC.gridx = 1;
GridC.gridy = 3;
myPanel.add(Login, GridC);
Login.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
/*
String my_name = textUsername.getText();
char [] my_password = passText.getPassword();
String my_stringword = new String(my_password);
*/
option ="log";
whileLog(option);
}
});
// adding create button gui next to user text field
GridC.gridx = 1;
GridC.gridy = 1;
myPanel.add(Create,GridC);
Create.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
option= "create";
whileLog(option);
}
});
add(myPanel); //adds gui to jframe
setSize(270,170); // creates dimensions of frame
setLocationRelativeTo(null); // center gui
setVisible(true); // I can see!
my_error = new JFrame("Error");
error = new JPanel(new GridBagLayout());
GridC.gridx= 1;
GridC.gridy = 1;
error.add(cancel_me,GridC);
cancel_me.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
my_error.setVisible(false);
}
});
GridC.gridy = 2;
error.add(errormsg,GridC);
my_error.add(error);
my_error.pack();
my_error.setLocationRelativeTo(null);
my_error.setVisible(false);
}
public class clientserver{
public static void main(String[]args) {
ClientGUI my_gui = new ClientGUI();
my_gui.CreatGui();
}
}
you need to set
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
For your ClientGui, otherwise the default kicks in, which makes it not really close. The default keeps the JVM running as the JFrame hasn´t been destroyed properly.
an additional small paragraph from the methods documentation, which shows what the default is.
[...]
HIDE_ON_CLOSE (defined in WindowConstants): Automatically hide the frame after invoking any registered WindowListener objects.
[...]
EXIT_ON_CLOSE (defined in JFrame): Exit the application using the System exit method. Use this only in applications.
[...]
The value is set to HIDE_ON_CLOSE by default. Changes to the value of this property cause the firing of a property change event, with property name "defaultCloseOperation".
[...]
There is 3 panels which I created as seen in the image. The first panel is the "From" panel, second is "To" panel, and third is the buttons panel. So the question is, how can I put a new line for the "Enter Temperature: [ ]" so that it will be under neath the radio buttons? I am very new to Java swing/awt please bear with me.
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.awt.*;
public class TemperatureConversion extends JFrame{
// component
JTextField txtFromTemp, txtToTemp;
JLabel lblFromTemp, lblToTemp;
JRadioButton radFromCelsius, radFromFahrenheit, radFromKelvin;
JRadioButton radToCelsius, radToFahrenheit, radToKelvin;
JPanel pnlFromRadioButton, pnlToRadioButton, pnlFromTemp, pnlButton;
ButtonGroup bgFrom, bgTo;
JButton btnConvert, btnExit;
// constructor
public TemperatureConversion(){
super("Temperature");
// assign objects
radFromCelsius = new JRadioButton("Celsius", true);
radFromFahrenheit = new JRadioButton("Fahrenheit");
radFromKelvin = new JRadioButton("Kelvin");
lblFromTemp = new JLabel("Enter Temperature: ");
pnlFromTemp = new JPanel();
btnConvert = new JButton("Convert");
btnExit = new JButton("Exit");
pnlButton = new JPanel();
txtFromTemp = new JTextField(3);
lblToTemp = new JLabel("Comparable Temperature: ");
txtToTemp = new JTextField(3);
// register the button to a listener
btnExit.addActionListener(new MyButtonListener());
btnConvert.addActionListener(new MyButtonListener());
// make the multiple choice exclusive but not a container
bgFrom = new ButtonGroup();
bgFrom.add(radFromCelsius);
bgFrom.add(radFromFahrenheit);
bgFrom.add(radFromKelvin);
// radio buttons
radToCelsius = new JRadioButton("Celsius");
radToFahrenheit = new JRadioButton("Fahrenheit", true);
radToKelvin = new JRadioButton("Kelvin");
// make the multiple choice exclusive
bgTo = new ButtonGroup();
bgTo.add(radToCelsius);
bgTo.add(radToFahrenheit);
bgTo.add(radToKelvin);
pnlFromRadioButton = new JPanel();
pnlToRadioButton = new JPanel();
// decorate the panel
pnlFromRadioButton.setBorder(BorderFactory.createTitledBorder("From"));
pnlToRadioButton.setBorder(BorderFactory.createTitledBorder("To"));
// add radiobutton to panel
pnlFromRadioButton.add(radFromCelsius);
pnlFromRadioButton.add(radFromFahrenheit);
pnlFromRadioButton.add(radFromKelvin);
pnlToRadioButton.add(radToCelsius);
pnlToRadioButton.add(radToFahrenheit);
pnlToRadioButton.add(radToKelvin);
// add button to panel
pnlButton.add(btnConvert);
pnlButton.add(btnExit);
// add label and txt field to panel
pnlFromRadioButton.add(lblFromTemp);
pnlFromRadioButton.add(txtFromTemp);
pnlToRadioButton.add(lblToTemp);
txtToTemp.setEditable(false);
pnlToRadioButton.add(txtToTemp);
// add panels to the frame
add(pnlFromRadioButton, BorderLayout.NORTH);
add(pnlToRadioButton, BorderLayout.CENTER);
add(pnlButton, BorderLayout.SOUTH);
setVisible(true);
setSize(400, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
}
// private inner class to handle button event
private class MyButtonListener implements ActionListener {
// must override actionPerformed method
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == btnConvert) {
if (radFromCelsius.isSelected())
System.out.print("exit");
} else if (e.getSource() == btnExit) {
System.exit(0);
}
}
}
public static void main(String[] args) {
new TemperatureConversion();
}
}
Nest more JPanels and use layout managers
For instance, in the JPanel where you want two lines, give it a BoxLayout oriented along the BoxLayout.PAGE_AXIS, and then add two more JPanels to this BoxLayout-using, a top JPanel with the radio buttons and bottom JPanel with the JLabel and JTextField (or whatever else you want in it).
Side note: this would be a great place to use an enum one called TempScale that had three values: CELSIUS, FAHRENHEIT, KELVIN. You could even give the enum the formulas for conversion to and from Kelvin.
For example:
import java.awt.Component;
import java.awt.event.*;
import java.util.HashMap;
import java.util.Map;
import javax.swing.*;
#SuppressWarnings("serial")
public class TempConversion2 extends JPanel {
private ToFromPanel fromPanel = new ToFromPanel("From", true);
private ToFromPanel toPanel = new ToFromPanel("To", false);
private ButtonPanel buttonPanel = new ButtonPanel(fromPanel, toPanel);
public TempConversion2() {
setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
add(fromPanel);
add(toPanel);
add(buttonPanel);
}
private static void createAndShowGui() {
TempConversion2 mainPanel = new TempConversion2();
JFrame frame = new JFrame("Temp Convert");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
#SuppressWarnings("serial")
class ButtonPanel extends JPanel {
public ButtonPanel(ToFromPanel fromPanel, ToFromPanel toPanel) {
add(new JButton(new ConvertAction("Convert", fromPanel, toPanel)));
add(new JButton(new ExitAction("Exit", KeyEvent.VK_X)));
}
}
#SuppressWarnings("serial")
class ConvertAction extends AbstractAction {
private ToFromPanel fromPanel;
private ToFromPanel toPanel;
public ConvertAction(String name, ToFromPanel fromPanel, ToFromPanel toPanel) {
super(name);
int mnemonic = (int) name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
this.fromPanel = fromPanel;
this.toPanel = toPanel;
}
#Override
public void actionPerformed(ActionEvent e) {
String text = fromPanel.getText();
try {
double fromTemp = Double.parseDouble(text.trim());
TempScale fromScale = fromPanel.getTempScalesPanel().getSelectedTempScale();
double kelvinValue = fromScale.convertToKelvin(fromTemp);
TempScale toScale = toPanel.getTempScalesPanel().getSelectedTempScale();
double toValue = toScale.convertFromKelvin(kelvinValue);
String toValueString = String.format("%.2f", toValue);
toPanel.setText(toValueString);
} catch (NumberFormatException e1) {
Component parentComponent = fromPanel;
String message = "Text must be a valid number: " + text;
String title = "Invalid Text Entered";
int messageType = JOptionPane.ERROR_MESSAGE;
JOptionPane.showMessageDialog(parentComponent, message, title, messageType);
fromPanel.setText("");
}
}
}
#SuppressWarnings("serial")
class ExitAction extends AbstractAction {
public ExitAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
#SuppressWarnings("serial")
class ToFromPanel extends JPanel {
private String title;
private TempScalesPanel tempScalesPanel = new TempScalesPanel();
private JTextField tempTextField = new JTextField(3);
public ToFromPanel(String title, boolean textFieldEnabled) {
this.title = title;
tempTextField.setFocusable(textFieldEnabled);
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new BoxLayout(bottomPanel, BoxLayout.LINE_AXIS));
bottomPanel.setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2));
bottomPanel.add(new JLabel("Temperature:"));
bottomPanel.add(Box.createHorizontalStrut(8));
bottomPanel.add(tempTextField);
setBorder(BorderFactory.createTitledBorder(title));
setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
add(tempScalesPanel);
add(bottomPanel);
}
public String getTitle() {
return title;
}
public TempScalesPanel getTempScalesPanel() {
return tempScalesPanel;
}
public String getText() {
return tempTextField.getText();
}
public void setText(String text) {
tempTextField.setText(text);
}
}
#SuppressWarnings("serial")
class TempScalesPanel extends JPanel {
private ButtonGroup buttonGroup = new ButtonGroup();
private Map<ButtonModel, TempScale> buttonTempMap = new HashMap<>();
public TempScalesPanel() {
for (TempScale tempScale : TempScale.values()) {
JRadioButton radioButton = new JRadioButton(tempScale.getName());
add(radioButton);
buttonGroup.add(radioButton);
buttonTempMap.put(radioButton.getModel(), tempScale);
// set first button as selected by default
if (buttonGroup.getSelection() == null) {
buttonGroup.setSelected(radioButton.getModel(), true);
}
}
}
public TempScale getSelectedTempScale() {
ButtonModel model = buttonGroup.getSelection();
return buttonTempMap.get(model);
}
}
This is the enum that I was talking about. Note that if you change the enum, and for instance add another temperature scale element, the program will automatically include it in the GUI and in the calculations. God I love Java and OOP.
public enum TempScale {
CELSIUS("Celsius", 1.0, -273.15),
FAHRENHEIT("Fahrenheit", 5.0 / 9.0, -459.67),
KELVIN("Kelvin", 1.0, 0.0);
private TempScale(String name, double ratioToKelvin, double absZero) {
this.name = name;
this.ratioToKelvin = ratioToKelvin;
this.absZero = absZero;
}
private String name;
private double ratioToKelvin;
private double absZero;
public String getName() {
return name;
}
public double getRatioToKelvin() {
return ratioToKelvin;
}
public double getAbsZero() {
return absZero;
}
public double convertToKelvin(double value) {
return (value - absZero) * ratioToKelvin;
}
public double convertFromKelvin(double kelvinValue) {
return (kelvinValue / ratioToKelvin) + absZero;
}
}
Always consider posting an MCVE.
For example you layout can be simplified and demonstrated with :
import java.awt.BorderLayout;
import java.awt.Label;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class TemperatureConversion extends JFrame{
JPanel pnlFromRadioButton, pnlToRadioButton, pnlFromTemp, pnlButton;
// constructor
public TemperatureConversion(){
pnlFromRadioButton = new JPanel();
pnlFromRadioButton.add(new Label("From Panel"));
pnlToRadioButton = new JPanel();
pnlToRadioButton.add(new Label("To Panel"));
pnlButton = new JPanel();
pnlButton.add(new Label("Buttons Panel"));
// add panels to the frame
add(pnlFromRadioButton, BorderLayout.NORTH);
add(pnlToRadioButton, BorderLayout.CENTER);
add(pnlButton, BorderLayout.SOUTH);
setVisible(true);
setSize(400, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
new TemperatureConversion();
}
}
Suppose you want to an "Enter Temperature: [ ]" label to show in a different "line" under From buttons, your constructor will change to :
public TemperatureConversion(){
//set a layout manger. You could use grid layout
//GridLayout gridLayout = new GridLayout(4, 1);
//Or BoxLayout
BoxLayout boxLayout = new BoxLayout(getContentPane(), BoxLayout.Y_AXIS); // top to bottom
setLayout(boxLayout);
pnlFromRadioButton = new JPanel();
pnlFromRadioButton.add(new Label("From Panel"));
//create a panel to hold the desired label
pnlFromTemp = new JPanel();
pnlFromTemp.add(new JLabel("Enter Temperature: [ ]"));//add label
pnlToRadioButton = new JPanel();
pnlToRadioButton.add(new Label("To Panel"));
pnlButton = new JPanel();
pnlButton.add(new Label("Buttons Panel"));
// add panels to the frame
//the panel will show in the order added
add(pnlFromRadioButton);
add(pnlFromTemp);
add(pnlToRadioButton);
add(pnlButton);
setVisible(true);
setSize(400, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
Sorry I am new to forums and am not familiar with posting etiquette for codes #c0der. But using GridLayout solved my problem and I want to show you what I did, it is a big mess but here it is. Here is my bizarre code but don't know how to reduce it any further. This is how it is suppose to look as I wanted and because now I understand what you mean by "Nest more JPanels and use layout managers" #Hovercraft Full of Eels:
my temperature program
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.awt.*;
public class TemperatureConversion extends JFrame {
// component
JTextField txtFromTemp, txtToTemp;
JLabel lblFromTemp, lblToTemp, lblToTempbox;
JRadioButton radFromCelsius, radFromFahrenheit, radFromKelvin;
JRadioButton radToCelsius, radToFahrenheit, radToKelvin;
JPanel pnlFromRadioButton, pnlToRadioButton, pnlFrom, pnlTo, pnlButton;
JPanel pnlEnterTemp, pnlComparableTemp;
ButtonGroup bgFrom, bgTo;
JButton btnConvert, btnExit;
// constructor
public TemperatureConversion() {
super("Temperature");
// assign objects
radFromCelsius = new JRadioButton("Celsius", true);
radFromFahrenheit = new JRadioButton("Fahrenheit");
radFromKelvin = new JRadioButton("Kelvin");
lblFromTemp = new JLabel("Enter Temperature: ");
pnlFrom = new JPanel();
btnConvert = new JButton("Convert");
btnExit = new JButton("Exit");
pnlButton = new JPanel();
txtFromTemp = new JTextField(3);
lblToTemp = new JLabel("Comparable Temperature: ");
txtToTemp = new JTextField(3);
pnlTo = new JPanel();
pnlEnterTemp = new JPanel();
pnlComparableTemp = new JPanel();
pnlFromRadioButton = new JPanel();
pnlToRadioButton = new JPanel();
// register the button to a listener
btnExit.addActionListener(new MyButtonListener());
btnConvert.addActionListener(new MyButtonListener());
// make the multiple choice exclusive but not a container
bgFrom = new ButtonGroup();
bgFrom.add(radFromCelsius);
bgFrom.add(radFromFahrenheit);
bgFrom.add(radFromKelvin);
// radio buttons
radToCelsius = new JRadioButton("Celsius");
radToFahrenheit = new JRadioButton("Fahrenheit", true);
radToKelvin = new JRadioButton("Kelvin");
// make the multiple choice exclusive
bgTo = new ButtonGroup();
bgTo.add(radToCelsius);
bgTo.add(radToFahrenheit);
bgTo.add(radToKelvin);
pnlFrom.setLayout(new GridLayout(2, 1));
pnlFrom.add(pnlFromRadioButton);
pnlFrom.add(pnlEnterTemp);
pnlTo.setLayout(new GridLayout(2, 1));
pnlTo.add(pnlToRadioButton);
pnlTo.add(pnlComparableTemp);
// decorate the panel
pnlFrom.setBorder(BorderFactory.createTitledBorder("From"));
pnlTo.setBorder(BorderFactory.createTitledBorder("To"));
// add radiobutton to panel
pnlFromRadioButton.add(radFromCelsius);
pnlFromRadioButton.add(radFromFahrenheit);
pnlFromRadioButton.add(radFromKelvin);
pnlToRadioButton.add(radToCelsius);
pnlToRadioButton.add(radToFahrenheit);
pnlToRadioButton.add(radToKelvin);
// add button to panel
pnlButton.add(btnConvert);
pnlButton.add(btnExit);
// add label and txt field to panel
pnlEnterTemp.add(lblFromTemp);
pnlEnterTemp.add(txtFromTemp);
pnlComparableTemp.add(lblToTemp);
txtToTemp.setEditable(false);
pnlComparableTemp.add(txtToTemp);
// add panels to the frame
add(pnlFrom, BorderLayout.NORTH);
add(pnlTo, BorderLayout.CENTER);
add(pnlButton, BorderLayout.SOUTH);
setVisible(true);
setSize(400, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
}
// private inner class to handle button event
private class MyButtonListener implements ActionListener {
// must override actionPerformed method
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == btnConvert) {
if (radFromCelsius.isSelected() && radToFahrenheit.isSelected()) {
int strInput = Integer.parseInt(txtFromTemp.getText());
int celsius = strInput * 9 / 5 + 32;
txtToTemp.setText(Integer.toString(celsius));
} else if (radFromCelsius.isSelected() && radToCelsius.isSelected() ||
radFromFahrenheit.isSelected() && radToFahrenheit.isSelected() ||
radFromKelvin.isSelected() && radToKelvin.isSelected()) {
txtToTemp.setText(txtFromTemp.getText());
} else if (radToCelsius.isSelected() && radFromFahrenheit.isSelected()) {
int strInput = Integer.parseInt(txtFromTemp.getText());
int fahrenheit = (strInput - 32) * 5 / 9;
txtToTemp.setText(Integer.toString(fahrenheit));
} else if (radFromKelvin.isSelected() && radToCelsius.isSelected()) {
double strInput = Integer.parseInt(txtFromTemp.getText());
double celsius = strInput - 273.15;
txtToTemp.setText(Double.toString(celsius));
} else if (radFromKelvin.isSelected() && radToFahrenheit.isSelected()) {
double strInput = Integer.parseInt(txtFromTemp.getText());
double fahrenheit = strInput - 459.67;
txtToTemp.setText(Double.toString(fahrenheit));
} else if (radFromCelsius.isSelected() && radToKelvin.isSelected()) {
double strInput = Integer.parseInt(txtFromTemp.getText());
double celsius = strInput + 273.15;
txtToTemp.setText(Double.toString(celsius));
} else if (radFromFahrenheit.isSelected() && radToKelvin.isSelected()) {
double strInput = Integer.parseInt(txtFromTemp.getText());
double fahrenheit = strInput + 255.37;
txtToTemp.setText(Double.toString(fahrenheit));
}
} else if (e.getSource() == btnExit) {
System.exit(0);
}
}
}
public static void main(String[] args) {
new TemperatureConversion();
}
}
By the way #Hovercraft Full Of Eels, your solution is way more efficient and advanced than my level of thinking. I am newbie to programming in general so bear with me on my messy code and organization lol. I have barely dipped my feet into OOP. I do have a sense of how you used enum for TempScale and I thank you for your suggestion. I will keep these in my notes as references.
I'm trying to make my text fields to be right aligned, but I'm not quite sure how to make them right aligned in the JTextField. I read that you can make the Jtextfield right jusitified, but I just can't find the correct syntax.
currently, they're left justified.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.TitledBorder;
public class RecursivePowerCalculator extends JFrame {
//text fields for base, exponent, and power.
private JTextField jtfBase = new JTextField();
private JTextField jtfExponent = new JTextField();
private JTextField jtfPower = new JTextField();
//button to press called calcuate
private JButton jbtCalculate = new JButton("Calculate");
//constructor
public RecursivePowerCalculator(){
jtfPower.setEditable(false);
JPanel p1 = new JPanel(new GridLayout(3,2));
p1.add(new JLabel("Base"));
p1.add(jtfBase);
p1.add(new JLabel("Exponent"));
p1.add(jtfExponent);
p1.add(new JLabel("Power"));
p1.add(jtfPower);
JPanel p2 =new JPanel(new FlowLayout(FlowLayout.CENTER));
p2.add(jbtCalculate);
//add the panels to the frame
add(p1, BorderLayout.CENTER);
add(p2, BorderLayout.SOUTH);
jbtCalculate.addActionListener(new ButtonListener());
}
private class ButtonListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e){
//get values from text fields
double base = Double.parseDouble(jtfBase.getText());
double exponent = Double.parseDouble(jtfExponent.getText());
String pNum = "" + (power(base, exponent));
jtfPower.setText(pNum);
}
private double power(double x, double y){
if ( y == 0)
return 1.0;
else
return power(x,y - 1) * x;
}
}
}
Use jtfPower.setHorizontalAlignment(JTextField.RIGHT);
See javadoc.
So I am working on this small program when I ran in to this problem.Its mostly about location set up with GridBagLayout it wont show me the text for the JLable.Another problem is that every ones in a will my progress that was working stops working and later comes back.Any idea what it is?I would also like some one too help me with the location problem I want to place the JTextField in the bottom left corner any help?I cant go around this problem and no info online to specifically help me.So maybe you can help me.Hers my code so far...
package Main;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class code extends JFrame{
public static JTextField consol;
public static String title = "Metal-Lock:The Start";
public static Dimension size = new Dimension(650, 550);
public static JPanel panel;
public static JButton enter;
public static JLabel output;
public static void main(String args[]) {
code frame = new code();
}
public code() {
setTitle(title);
setSize(size);
setResizable(true);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
// VISITOR LIST
CONSOL();
P1();
P2();
}
//******************************************************************************************************************************
public void CONSOL() {
consol = new JTextField(30);
consol.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e){
String input = consol.getText();
output.setText(input);
}});
final JButton enter = new JButton("Enter");
enter.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e){
String input = consol.getText();
output.setText(input);
panel.add(consol);
add(panel);
panel.add(enter);
add(panel);
output = new JLabel();
panel.add(output);
add(panel);
}
});
}
//******************************************************************************************************************************
public void P1() {
}
//******************************************************************************************************************************
public static JLabel grid1;
public static JLabel grid2;
public static JLabel grid3;
public static JLabel grid4;
public static JLabel grid5;
public void P2() {
JPanel panel = new JPanel(new GridBagLayout());
GridBagConstraints R = new GridBagConstraints();
JLabel grid1 = new JLabel ("Hello"); panel.add(grid1, R);
R.gridx = 0; R.gridy = 0;
JLabel grid2 = new JLabel ("Hello"); panel.add(grid2, R);
R.gridx = 0; R.gridy = 0;
JLabel grid3 = new JLabel ("Hello"); panel.add(grid3, R);
R.gridx = 0; R.gridy = 0;
JLabel grid4 = new JLabel ("Hello"); panel.add(grid4, R);
R.gridx = 0; R.gridy = 0;
JLabel grid5 = new JLabel ("Hello"); panel.add(grid5, R);
R.gridx = 0; R.gridy = 0;
}
}
Just went really quickly through your code.
Change these lines:
GridBagConstraints R = new GridBagConstraints();
R.gridx = 0; R.gridy = 0;
JLabel grid1 = new JLabel ("Hello");
//important to set these R values BEFORE you ad grid1.
panel.add(grid1, R);
Change this in all lines there...
You are adding 6 Labels all to the location gridx=0 and gridy=0, which is wrong. Imagine it like an excel tabel, you are inserting every label to field 1.
If you want to add fields do it like this
E.g.
x y
z
//a.gridx=0; a.gridy=0;
//y.gridx=1; y.gridy=0;
//z.gridx=0; z.gridy=1;
x coordinates are horizontal.
y are vertical starting from the top left corner.
Read this article, it's really good:
http://docs.oracle.com/javase/tutorial/uiswing/layout/gridbag.html
This is for a Java program I'm working on as part of a homework assignment. I don't want the work done for me, but I'm stuck. I'm fairly new to Java, and using NetBeans IDE 7.0.1.
I'm having difficulty with some exception handling when trying to validate user input. This program will log charitable donations from user input. However, I've not been successful in validating the donation amount text field input. If a user inputs text instead of numbers, I would like them to be notified that their input was invalid, and I'd like the exception handling to handle the error and carry on after the user fixes their entry. Any help is greatly appreciated.
Here is my code:
package donorgui;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.io.*;
import java.awt.*;
public class DonorGUI extends JFrame
{
// Components
private JPanel panel;
private JTextArea results;
private JButton entryButton;
private JButton exitButton;
private JButton clearButton;
private JTextField donorField;
private JTextField charityField;
private JTextField pledgeField;
//create variables
String[] donorName = new String[20];
String[] charityName = new String[20];
double[] donationAmt = new double[20];
int i = 0;
// Constants for the window size
private final int WINDOW_WIDTH = 750;
private final int WINDOW_HEIGHT = 510;
//Constructor
public DonorGUI(){
// Set the title.
setTitle("Donor");
// Specify what happens when the close button is clicked.
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Build the panel that contains the other components.
buildPanel();
// Add the panel to the content pane.
add(panel);
// Size and display the window.
setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
setVisible(true);
}
//The buildPanel method creates a panel containing other components.
private void buildPanel(){
// Create labels to display instructions.
JLabel message1 = new JLabel("Name of the Donor:");
JLabel message2 = new JLabel("Name of the Charity:");
JLabel message3 = new JLabel("Amount of the Pledge:");
//instantiate the results area
results = new JTextArea(25,60);
// Create text fields to receive user input
donorField = new JTextField(10);
charityField = new JTextField(10);
pledgeField = new JTextField(10);
//create the user buttons to cause action
entryButton = new JButton("Enter Donation.");
entryButton.addActionListener(new EntryButtonListener());
exitButton = new JButton("EXIT");
exitButton.addActionListener(new ExitButtonListener());
clearButton = new JButton ("Clear Fields");
clearButton.addActionListener(new ClearButtonListener());
// Create a panel.
panel = new JPanel();
//set the LayoutManager
panel.setLayout(new FlowLayout());
// Add the labels, text fields, and button to the panel.
panel.add(message1);
panel.add(donorField);
panel.add(message2);
panel.add(charityField);
panel.add(message3);
panel.add(pledgeField);
panel.add(results);
panel.add(entryButton);
panel.add(exitButton);
panel.add(clearButton);
}
private class EntryButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
donorName[i] = donorField.getText();
charityName[i] = charityField.getText();
donationAmt[i] = Double.parseDouble(pledgeField.getText());
results.append(donorName[i]+" "+charityName[i]+" "+donationAmt[i]+"\n ");
i++;
}
}
public boolean donationAmt(String amount) {
int i = 0;
try {
i = Integer.parseInt (amount);
return true;
}
catch (NumberFormatException e) {
JOptionPane.showMessageDialog(null, "Invalid Input. Please enter a dollar amount");
return false;
}
}
private class ClearButtonListener implements ActionListener {
#Override
public void actionPerformed (ActionEvent e) {
donorField.setText("");
charityField.setText("");
pledgeField.setText("");
}
}
private class ExitButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
/* Application method */
public static void main(String[] args){
DonorGUI rpc = new DonorGUI();
}
}
Here is my revised code. After some user input testing, I'm getting an exception when I use 100.00, 40.00, etc... instead of whole dollar amounts, such as 100, 40, etc.
Any thoughts?
package donorgui;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.io.*;
import java.awt.*;
public class DonorGUI extends JFrame
{
// Components
private JPanel panel;
private JTextArea results;
private JButton entryButton;
private JButton exitButton;
private JButton clearButton;
private JTextField donorField;
private JTextField charityField;
private JTextField pledgeField;
//create variables
String[] donorName = new String[20];
String[] charityName = new String[20];
double[] donationAmt = new double[20];
int i = 0;
// Constants for the window size
private final int WINDOW_WIDTH = 750;
private final int WINDOW_HEIGHT = 550;
//Constructor
public DonorGUI(){
// Set the title.
setTitle("Donor");
// Specify what happens when the close button is clicked.
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Build the panel that contains the other components.
buildPanel();
// Add the panel to the content pane.
add(panel);
// Size and display the window.
setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
setVisible(true);
}
//The buildPanel method creates a panel containing other components.
private void buildPanel(){
// Create labels to display instructions.
JLabel message1 = new JLabel("Name of the Donor:");
JLabel message2 = new JLabel("Name of the Charity:");
JLabel message3 = new JLabel("Amount of the Pledge:");
//instantiate the results area
results = new JTextArea(25,60);
// Create text fields to receive user input
donorField = new JTextField(10);
charityField = new JTextField(10);
pledgeField = new JTextField(10);
//create the user buttons to cause action
entryButton = new JButton("Enter Donation.");
entryButton.addActionListener(new EntryButtonListener());
exitButton = new JButton("EXIT");
exitButton.addActionListener(new ExitButtonListener());
clearButton = new JButton ("Clear Fields");
clearButton.addActionListener(new ClearButtonListener());
// Create a panel.
panel = new JPanel();
//set the LayoutManager
panel.setLayout(new FlowLayout());
// Add the labels, text fields, and button to the panel.
panel.add(message1);
panel.add(donorField);
panel.add(message2);
panel.add(charityField);
panel.add(message3);
panel.add(pledgeField);
panel.add(results);
panel.add(entryButton);
panel.add(exitButton);
panel.add(clearButton);
}
private class EntryButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
donorName[i] = donorField.getText();
charityName[i] = charityField.getText();
if (donationAmt(pledgeField.getText())) {
donationAmt[i] = Double.parseDouble(pledgeField.getText());
}
results.append(donorName[i]+" "+charityName[i]+" "+donationAmt[i]+"\n ");
i++;
}
}
public boolean donationAmt(String amount) {
if(amount==null || amount=="" || amount.length()<1){ //checking for empty field
JOptionPane.showMessageDialog(null, "Please enter a dollar amount");
return false;
}
for(int i = 0; i < amount.length(); i++){ //verifying dollar amount entered as number
if (!Character.isDigit(amount.charAt(i))){
JOptionPane.showMessageDialog(null, "Invalid input. Please enter a dollar amount");
return false;
}
}
return true;
}
private class ClearButtonListener implements ActionListener {
#Override
public void actionPerformed (ActionEvent e) {
donorField.setText("");
charityField.setText("");
pledgeField.setText("");
}
}
private class ExitButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
/* Application method */
public static void main(String[] args){
DonorGUI rpc = new DonorGUI();
}
}
You can use InputVerifier, discussed here.
private class EntryButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
donorName[i] = donorField.getText();
charityName[i] = charityField.getText();
if(donationAmt(pledgeField.getText())){
donationAmt[i] = Double.parseDouble(pledgeField.getText());
results.append(donorName[i] + " " + charityName[i] + " " + donationAmt[i] + "\n ");
i++;
}
}
}
Something like this would work. This checks so that the amount is not empty and contains only digits based on your exisiting method.
public boolean donationAmt(String amount) {
if(amount==null || amount=="" || amount.length()<1){ //check so that the amount field is not empty, pherhaps you can add a check so the amound is not 0 :)
JOptionPane.showMessageDialog(null, "Invalid Input. The amount cannot be empty");
return false;
}
for(int i = 0; i < amount.length(); i++){ //loop thru the string and check so that each char is a digit
if (!Character.isDigit(amount.charAt(i))){
JOptionPane.showMessageDialog(null, "The amount can contain only numbers");
return false;
}
return true;
If you want to make sure that the amount is not 0, one approach would be to parse amount to int, and check so that parsedAmount<0. This should be done after it's verified that the amount is not empty and is only digits (e.i last:) ) to avoid NPE's and numberformatexception