Develop Reference

JRadioButton java

I'm new to java GUI programming and while working on the project I'm getting the error cannot find symbol on my addActionListener for my JRadioButtons, I'm not quite sure what I'm doing wrong since I didn't receive the same error when working with JButtons.
Here's my code:
public void SouthPanel() {
JRadioButton greenButton = new JRadioButton("Green");
JRadioButton blueButton = new JRadioButton("Blue");
JRadioButton cyanButton = new JRadioButton("Cyan");
ButtonGroup group = new ButtonGroup();
group.add(greenButton);
group.add(blueButton);
group.add(cyanButton);
greenButton.addActionListener(new RadioButtonListener());
blueButton.addActionListener(new RadioButtonListener());
cyanButton.addActionListener(new RadioButtonListener());
SouthPanel = new JPanel();
add(greenButton);
add(blueButton);
add(cyanButton);
add(SouthPanel);
setVisible(true);
}
private class RadioButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
String actionRadio = e.getActionCommand();
if (actionRadio.equals("Green")) {
label.setForeground(Color.GREEN);
}
else if (actionRadio.equals("Blue")) {
label.setForeground(Color.BLUE);
}
else if (actionRadio.equals("Cyan")) {
label.setForeground(Color.CYAN);
}
}

To my knowledge, the error "cannot find symbol" usually refers to a variable that can't be resolved by the compiler.
On what line does the error occur?
What seems a bit odd at first glance is following statement:
SouthPanel = new JPanel();
and add(SouthPanel);
since SouthPanel is the name of your method and you didn't give a name to your SouthPanel (?) object.

To use getActionCommand() on a Button or RadioButton, you should have previously set the ActionCommand
button.setActionCommand(String val);
You'd be able to get it back when you make a call to:
button.getActionCommand(); //This would return the string you previously set.
For a TextField, ActionCommand would give you the text in the TextField by default if you do not set it.
That's where you are probably missing the line.

You have created an instance of the JPanel and inserted into SouthPanel class. How can it be done.
SouthPanel = new JPanel();
add(greenButton);
add(blueButton);
add(cyanButton);
add(SouthPanel);
setVisible(true);
Into where are you adding the buttons and adding the SouthPanel.! Please check this one.Seems the error is from here.3 buttons are added,for 3 times and error is shown for 3 times.right.Seems error is from here. Check here.

See the complete code here.
class SouthPanel extends JPanel {
JLabel label = new JLabel("label");
public SouthPanel() {
JRadioButton greenButton = new JRadioButton("Green");
JRadioButton blueButton = new JRadioButton("Blue");
JRadioButton cyanButton = new JRadioButton("Cyan");
ButtonGroup group = new ButtonGroup();
group.add(greenButton);
group.add(blueButton);
group.add(cyanButton);
greenButton.addActionListener((ActionListener) new
RadioButtonListener());
blueButton.addActionListener(new RadioButtonListener());
cyanButton.addActionListener(new RadioButtonListener());
JPanel SouthPanel = new JPanel();
add(label);
add(greenButton);
add(blueButton);
add(cyanButton);
add(SouthPanel);
setVisible(true);
JFrame frame = new JFrame();
frame.setContentPane(this);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
new SouthPanel();
}
private class RadioButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
String actionRadio = e.getActionCommand();
if (actionRadio.equals("Green")) {
label.setForeground(Color.GREEN);
} else if (actionRadio.equals("Blue")) {
label.setForeground(Color.BLUE);
} else if (actionRadio.equals("Cyan")) {
label.setForeground(Color.CYAN);
}
}
}
}

Java Button disappears after clicking

I'm trying to add a button using an JOptionPane in another button, but after I clicked the original button just keeps disappearing.
I've tried adding the JPanel manually instead of using 'handPanelNPC.getHandPanel()' by iterating through the handPanel.buttons but it stil wont work. I've checked the ArrayList size and it is already inserted properly.
LayoutTesting.java
public class LayoutTesting extends JFrame{
HandPanel handPanelNPC = new HandPanel();
public LayoutTesting(HandPanel handPanel, int type){
Container pane = getContentPane();
if (type==1){
handPanelNPC = handPanel;
}
pane.setLayout(new BorderLayout());
pane.add(handPanelNPC.getHandPanel(), BorderLayout.NORTH);
validate();
repaint();
}
public LayoutTesting(){
Container pane = getContentPane();
pane.setLayout(new BorderLayout());
pane.add(handPanelNPC.getHandPanel(), BorderLayout.NORTH);
}
}
HandPanel.java
public class HandPanel implements ActionListener{
JFrame frame = null;
JPanel panel = new JPanel();
ArrayList<JButton> buttons = new ArrayList<JButton>();
public HandPanel(){
addNewButton();
panel.setLayout(new FlowLayout());
panel.add(buttons.get(0));
}
public JComponent getHandPanel(){
panel = new JPanel();
for(int i=0; i<buttons.size(); i++){
JButton button = buttons.get(i);
panel.add(button);
}
return panel;
}
public void addNewButton(){
JButton button = new JButton();
button.setPreferredSize(new Dimension(40,58));
button.addActionListener(this);
buttons.add(button);
}
public void actionPerformed(ActionEvent e) {
String[] options = {"Summon", "Set", "Add Card"};
int messageType = JOptionPane.QUESTION_MESSAGE;
int code = JOptionPane.showOptionDialog(
frame,
"What would you like to do?",
"Card Name",
0, messageType, null,
options, options[1]);
if (code==2){
addNewButton();
LayoutTesting frame = new LayoutTesting(this, 1);
}
}
}
Main.java
public class Main extends JFrame{
public static void main(String[] args){
LayoutTesting frame = new LayoutTesting();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 300);
frame.setVisible(true);
}
}

You have too many odd things happening in your code to give a simple answer.
Try debugging your own code by looking at this line in HandPanel.java:
LayoutTesting frame = new LayoutTesting(this, 1);
What does it really do? Now remove that line and the button will not disappear. Now try and work out what that line was doing, and why the button disappeared.
Also 'panel.add(buttons.get(0));' does nothing because there is never a button in the array when you make that call (You add the button afterwards in another method).
Here is a rough working demo that lets you add as many new cards as you want to the first frame, and each card has a button that will let you summon a new card.
public class LayoutTesting extends JFrame{
Container pane;
//Add card when button is pressed:
public void addCard(){
Container card = new JPanel();
card.setBackground(Color.red);
JButton newButton = addNewButton();
newButton.setBackground(Color.red);
card.add(newButton);
pane.add(card);
revalidate();
repaint();
}
//Setup window and add button:
public LayoutTesting(){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(400, 300);
setVisible(true);
setLayout(new FlowLayout());
pane = new JPanel();
pane.setLayout(new GridBagLayout());
JButton firstButton = addNewButton();
firstButton.setBackground(Color.green);
add(pane);
add(firstButton);
}
//Create button and action listener:
public JButton addNewButton(){
JButton button = new JButton();
button.setPreferredSize(new Dimension(40, 58));
button.addActionListener(new java.awt.event.ActionListener(){
#Override
public void actionPerformed(java.awt.event.ActionEvent evt){
buttonAction(evt);
}
});
return button;
}
//Action fer each button:
public void buttonAction(ActionEvent e) {
String[] options = {"Summon", "Set", "Add Card"};
int messageType = JOptionPane.QUESTION_MESSAGE;
int code = JOptionPane.showOptionDialog(
this,
"What would you like to do?",
"Card Name",
0, messageType, null,
options, options[1]);
if (code==2){
addCard();
}
}
}

Button in java not doing action

I'm working on a Java assignment. I have many classes linked together and one of the constructors is the following:
public class RemovePatientForm extends JFrame implements ActionListener {
JPanel northPanel = new JPanel();
JPanel southPanel = new JPanel();
JPanel midPanel = new JPanel();
JLabel removeLabel = new JLabel("Please type in the ID of the patient to be removed");
JLabel idLabel= new JLabel("ID");
JTextField idText=new JTextField();
JButton submit = new JButton("Submit");
JButton reset = new JButton("Clear");
boolean externalForm = false;
public RemovePatientForm(){
setTitle("Removing a patient");
setLayout(new BorderLayout());
setSize(400,200);
setLocationRelativeTo(null);
setVisible(true);
setResizable(false);
add("North", northPanel);
add("South", southPanel);
northPanel.add(removeLabel);
southPanel.add(submit);
southPanel.add(reset);
add(idLabel);
add(idText);
submit.addActionListener(this);
}
#Override
public void actionPerformed(ActionEvent arg0) {
if(arg0.getSource()==submit){
if(!(idText.getText().equals(""))){
int selectedvalue = JOptionPane.showConfirmDialog(null, "Do you want to proceed with the deletion?", "do you want to proceed with the deletion?", JOptionPane.YES_NO_OPTION);
if(selectedvalue==JOptionPane.YES_OPTION){
int id=Integer.parseInt(idText.getText());
if(searchForId(id)){
removeToDatabase();
dispose();
}
else{
JOptionPane.showMessageDialog(null,"This ID is not available!","Warning",JOptionPane.ERROR_MESSAGE);
}
}
else{
JOptionPane.showMessageDialog(null, "Nothing is affected!");
}
}
else{
JOptionPane.showMessageDialog(null,"You have to fill the ID number!","Warning",JOptionPane.ERROR_MESSAGE);
}
}
if(arg0.getSource()==reset && externalForm==false){
idText.setText("");
}
}
The problem in here is that when I press the submit button, everything is okay and working as written within the code.
But, if I press the reset button, nothing is happening.
What do you think the solution is? is this code enough to determine the problem?

You didn't add an action listener for the reset button.. i think you forgot it. Try to add it and it should work.
Add this code within your constructor:
reset.addActionListener(this);

How do you open a new JPanel window on a click of a button?

I am new to JSwing and I would like to ask a question regarding opening new JPanels on a click of a button.
public class GUIDriver extends JFrame implements ActionListener {
private JPanel mainPanel;
private JButton regButton;
private JButton loginButton;
private JButton acctButton;
public GUIDriver(){
super("FriendBook");
mainPanel = new JPanel();
regButton = new JButton("Register Account");
loginButton = new JButton("Login");
acctButton = new JButton("View Accounts");
mainPanel.add(regButton);
mainPanel.add(loginButton);
mainPanel.add(acctButton);
regButton.addActionListener(this);
loginButton.addActionListener(this);
acctButton.addActionListener(this);
getContentPane().add(mainPanel);
setSize(300,300);
}
public static void main(String[] args){
GUIDriver myDriver = new GUIDriver();
myDriver.setVisible(true);
myDriver.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
#Override
public void actionPerformed(ActionEvent e){
if(e.getSource() == regButton){
JPanel register = new JPanel();
register.setSize(new Dimension(400,100));
JLabel username = new JLabel("Username");
JLabel password = new JLabel("Password");
JButton registerBT = new JButton("Register Account");
JTextField uname = new JTextField(20);
JTextField pass = new JTextField(20);
register.add(username);
register.add(uname);
register.add(password);
register.add(pass);
register.add(registerBT);
register.setVisible(true);
}
else if(e.getSource() == loginButton){
System.out.print("LOGIN");
}
else if (e.getSource() == acctButton){
System.out.print("VIEW ACCOUNTS");
}
}
}
The programs shows three buttons (Register, Login and View). I would like to open a new JPanel window when I click on the Register button but it does not show. Please help me, I am new to JSwing/Java GUI. Thank you!

A JPanel needs something that wraps around in order to be displayed; you have to create another "windows"; for example a JDialog. Then you add the created panel to that "window".
In other words: just creating a JPanel is not sufficient to make it visible.

Set JLabel Visible when JButton is clicked in actionPerformed

I am trying to get a JLabel to appear when a JButton is clicked. I have added an action listener and added the component to the layout. I am using the label1.setVisible(true) when the JButton is clicked in actionPerformed. I still can't get it work. Can some look at my code?
public class LearnAppMain extends JFrame implements ActionListener {
// Define variables
public JButton button1;
public JLabel label1;
public JTextField field1;
private Image image1;
private String apple = "apple.jpg";
public LearnAppMain() {
ImageIcon image1 = new ImageIcon(this.getClass().getResource(apple));
JLabel label1 = new JLabel(image1);
button1 = new JButton("A");
button1.addActionListener(this);
field1 = new JTextField(10);
// Create layout
setLayout(new FlowLayout());
// create Container
final Container cn = getContentPane();
cn.add(button1);
cn.add(field1);
cn.add(label1);
// setLayout(new FlowLayout());
setSize(250, 250);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
#Override
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
if (e.getSource() == button1) {
label1.setVisible(true);
field1.setText("Apple");
}
}
}
I have my main method in another class file. The error I get leads me to the label1.setVisible(true);
Every question I've seen they say to do this, but I'm wondering if there is something else that needs to be added.

There were a couple of issues here:
Your label1 was hidden by doing JLabel label in the constructor. You basically declared another variable called label1 in your constructor that hid the one in the class itself.
Your label was visible on the startup - I used label.setVisible(false) for the test, but you might want otherwise
I also put the creation of Image aside as I did not have an image, so uncomment that and change as appropriate.
Here's a complete working version:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class LearnAppMain extends JFrame implements ActionListener {
// Define variables
public JButton button1;
public JLabel label1;
public JTextField field1;
private Image image1;
private String apple = "apple.jpg";
public LearnAppMain() {
//ImageIcon image1 = new ImageIcon(this.getClass().getResource(apple));
//JLabel label1 = new JLabel(image1);
label1 = new JLabel("hello");
label1.setVisible(false);
button1 = new JButton("A");
button1.addActionListener(this);
field1 = new JTextField(10);
// Create layout
setLayout(new FlowLayout());
// create Container
final Container cn = getContentPane();
cn.add(button1);
cn.add(field1);
cn.add(label1);
// setLayout(new FlowLayout());
setSize(250, 250);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
#Override
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
if (e.getSource() == button1) {
label1.setVisible(true);
field1.setText("Apple");
}
}
public static void main(String[] args) {
new LearnAppMain();
}
}
I'd suggest using separate (usually inner-class) ActionListener instances instead of overriding actionPerformed. See e.g. this for a similar example if you are interested:
http://docs.oracle.com/javase/tutorial/displayCode.html?code=http://docs.oracle.com/javase/tutorial/uiswing/examples/events/BeeperProject/src/events/Beeper.java
Also, if you are using this in a bigger application (i.e. not just experimenting or for prototyping), make sure all Swing code is run on EDT.
You typically use SwingUtilities.invokeLater for that purpose.
Hope this helps.

first you don't add the image first itself to JLabel.
just create the object and leave it like..
ImageIcon image1 = new ImageIcon(this.getClass().getResource(apple));
JLabel label1 = new JLabel("");
label1.setVisible(true);
then do the modification in the action performed
public void actionPerformed(ActionEvent e) {
if (e.getSource() == button1)
{
field1.seticon(image1);
field1.revalidate();
}
it will definitely works

clientDetail.addActionListener(new ActionListener(){
public void actionPerformed (ActionEvent e){
d.getContentPane().removeAll();
g = new GridBagLayout();
gc = new GridBagConstraints();
d.setLayout(g);
JLabel message= new JLabel(" Message");
addComponent(message,5,1,1,2);
JTextArea Message = new JTextArea();
addComponent(Message,5,1,1,2);
d.setVisible(true);
d.setVisible(true);
d.pack();
}
private void addComponent(Component component, int i, int i0, int i1, int i2) {
gc.gridx=i;
gc.gridy=i0;
gc.gridheight=i1;
gc.gridwidth=i2;
g.setConstraints(component, gc);
add(component);
}
});
Recep.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
}
});