问题
Please I have been trying to switch CardLayout from another class (JPanel) which is one of the card on the CardLayout, I have search and made research about this for a very long time but found nothing helpful.
I have a CardLayout and two separate JPanels that I added to the CardLayout, now I want to be able to switch the cards after performing activities on the separate JPanel or separate class, so how do I switch the CardLayout from another class? my code below.
package myApp;
import java.awt.CardLayout;
public class TestmyCard extends javax.swing.JFrame {
/**
* Creates new form TestmyCard
*/
public TestmyCard() {
initComponents();
jPanel1.add(new FirstCard(),"card3");
jPanel1.add(new SecondCard(),"card4");
}
public void chgCard(String nwCard){
CardLayout cl = (CardLayout)(jPanel1.getLayout());
cl.show(jPanel1,nwCard);
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanel1 = new javax.swing.JPanel();
jPanel2 = new javax.swing.JPanel();
jLabel1 = new javax.swing.JLabel();
jPanel3 = new javax.swing.JPanel();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setName("Cards");
jPanel1.setLayout(new java.awt.CardLayout());
jPanel2.setName("card2");
jLabel1.setText("second panel");
javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
jPanel2.setLayout(jPanel2Layout);
jPanel2Layout.setHorizontalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addGap(119, 119, 119)
.addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 117, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(203, Short.MAX_VALUE))
);
jPanel2Layout.setVerticalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addGap(140, 140, 140)
.addComponent(jLabel1)
.addContainerGap(92, Short.MAX_VALUE))
);
jPanel1.add(jPanel2, "card2");
jPanel3.setBackground(new java.awt.Color(153, 255, 153));
jButton1.setLabel("First Btn");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jButton2.setLabel("Second Btn");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
jPanel3.setLayout(jPanel3Layout);
jPanel3Layout.setHorizontalGroup(
jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel3Layout.createSequentialGroup()
.addContainerGap()
.addComponent(jButton1)
.addGap(18, 18, 18)
.addComponent(jButton2)
.addContainerGap(181, Short.MAX_VALUE))
);
jPanel3Layout.setVerticalGroup(
jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel3Layout.createSequentialGroup()
.addContainerGap(27, Short.MAX_VALUE)
.addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jButton2))
.addGap(20, 20, 20))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, 439, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(0, 0, Short.MAX_VALUE))
.addGroup(layout.createSequentialGroup()
.addGap(37, 37, 37)
.addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, 246, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 25, Short.MAX_VALUE)
.addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap())
);
pack();
}// </editor-fold>
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
CardLayout cl = (CardLayout)(jPanel1.getLayout());
cl.show(jPanel1,"card3");
//cl.next(jPanel1) ;
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
CardLayout cl = (CardLayout)(jPanel1.getLayout());
cl.show(jPanel1,"card4");
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/*
* Set the Nimbus look and feel
*/
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/*
* If Nimbus (introduced in Java SE 6) is not available, stay with the
* default look and feel. For details see
* http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(TestmyCard.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(TestmyCard.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(TestmyCard.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(TestmyCard.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/*
* Create and display the form
*/
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new TestmyCard().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JLabel jLabel1;
private javax.swing.JPanel jPanel1;
private javax.swing.JPanel jPanel2;
private javax.swing.JPanel jPanel3;
// End of variables declaration
}
FirstCard (separate jpanel)
package myApp;
public class FirstCard extends javax.swing.JPanel {
/**
* Creates new form FirstCard
*/
public FirstCard() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
guName = new javax.swing.JTextField();
guAddrs = new javax.swing.JTextField();
jLabel14 = new javax.swing.JLabel();
jLabel15 = new javax.swing.JLabel();
guOccu = new javax.swing.JTextField();
jLabel16 = new javax.swing.JLabel();
guPhone = new javax.swing.JTextField();
jLabel1.setText("Guarantee Name :");
jLabel14.setText("Address :");
jLabel15.setText("Occupation :");
jLabel16.setText("Phone :");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
this.setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel14)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(guAddrs, javax.swing.GroupLayout.PREFERRED_SIZE, 158, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel16)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(guPhone, javax.swing.GroupLayout.PREFERRED_SIZE, 158, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel15)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(guOccu, javax.swing.GroupLayout.PREFERRED_SIZE, 158, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(guName, javax.swing.GroupLayout.PREFERRED_SIZE, 158, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addContainerGap(228, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(43, 43, 43)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(guName, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel15)
.addComponent(guOccu, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(30, 30, 30)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel14)
.addComponent(guAddrs, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel16)
.addComponent(guPhone, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(135, Short.MAX_VALUE))
);
}// </editor-fold>
// Variables declaration - do not modify
private javax.swing.JTextField guAddrs;
private javax.swing.JTextField guName;
private javax.swing.JTextField guOccu;
private javax.swing.JTextField guPhone;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel14;
private javax.swing.JLabel jLabel15;
private javax.swing.JLabel jLabel16;
// End of variables declaration
}
SecondCard (separate jpanel)
package myApp;
public class SecondCard extends javax.swing.JPanel {
/**
* Creates new form SecondCard
*/
public SecondCard() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
jButton1 = new javax.swing.JButton();
jLabel1.setText("this is the second card");
jButton1.setText("SwitchCard");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
this.setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(120, 120, 120)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jButton1)
.addComponent(jLabel1))
.addContainerGap(173, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(62, 62, 62)
.addComponent(jLabel1)
.addGap(18, 18, 18)
.addComponent(jButton1)
.addContainerGap(183, Short.MAX_VALUE))
);
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
TestmyCard nc = new TestmyCard();
nc.chgCard("Card2");
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
// End of variables declaration
}
回答1:
In your provided code, you never added FirstCard and SecondCard, to the JPanel having layout set to CardLayout. Since what you writing is this :
jPanel1.add(jPanel2, "card2");
here jPanel2 is an instance of JPanel, as you have initialized this in your TestmyClass Class, as :
jPanel2 = new javax.swing.JPanel();
instead I guess what you should be writing is :
jPanel2 = new SecondCard(passPanelWithCardLayoutAsArgument); // So that you can manoeuvre around b/w other JPanels
Here is a small working example for your help :
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class CardLayoutExample
{
private JPanel contentPane;
private MyPanel panel1;
private MyPanel panel2;
private MyPanel panel3;
private void displayGUI()
{
JFrame frame = new JFrame("Card Layout Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setBorder(
BorderFactory.createEmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new CardLayout());
panel1 = new MyPanel(contentPane
, Color.RED.darker().darker());
panel2 = new MyPanel(contentPane
, Color.GREEN.darker().darker());
panel3 = new MyPanel(contentPane
, Color.DARK_GRAY);
contentPane.add(panel1, "Panel 1");
contentPane.add(panel2, "Panel 2");
contentPane.add(panel3, "Panel 3");
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new CardLayoutExample().displayGUI();
}
});
}
}
class MyPanel extends JPanel
{
private JButton jcomp1;
private JPanel contentPane;
private Color backgroundColour;
public MyPanel(JPanel panel, Color c)
{
contentPane = panel;
backgroundColour = c;
setOpaque(true);
setBackground(backgroundColour);
//construct components
jcomp1 = new JButton ("Show New Panel");
jcomp1.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.next(contentPane);
}
});
add(jcomp1);
}
@Override
public Dimension getPreferredSize()
{
return (new Dimension(500, 500));
}
}
LATEST EDIT : *Using your components and trying to put that into CardLayout, with this code : *
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class CardLayoutExample
{
private JPanel contentPane;
private FirstCard panel1;
private SecondCard panel2;
private void displayGUI()
{
JFrame frame = new JFrame("Card Layout Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setBorder(
BorderFactory.createEmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new CardLayout());
panel1 = new FirstCard(contentPane);
panel2 = new SecondCard(contentPane);
contentPane.add(panel1, "Panel 1");
contentPane.add(panel2, "Panel 2");
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new CardLayoutExample().displayGUI();
}
});
}
}
class FirstCard extends javax.swing.JPanel
{
private javax.swing.JTextField addField;
private javax.swing.JTextField nameField;
private javax.swing.JTextField occField;
private javax.swing.JTextField phoneField;
private javax.swing.JLabel nameLabel;
private javax.swing.JLabel addLabel;
private javax.swing.JLabel occLabel;
private javax.swing.JLabel phoneLabel;
private JPanel centerPanel;
private JPanel contentPane;
private JButton nextButton;
public FirstCard(JPanel cp)
{
this.contentPane = cp;
initComponents();
}
private void initComponents()
{
setOpaque(true);
setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
setBackground(Color.RED);
setLayout(new BorderLayout(5, 5));
nameLabel = new javax.swing.JLabel("Guarantee Name : ");
nameField = new javax.swing.JTextField();
addLabel = new javax.swing.JLabel("Address : ");
addField = new javax.swing.JTextField();
occLabel = new javax.swing.JLabel("Occupation : ");
occField = new javax.swing.JTextField();
phoneLabel = new javax.swing.JLabel("Phone : ");
phoneField = new javax.swing.JTextField();
centerPanel = new JPanel();
nextButton = new JButton("Next");
nextButton.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent ae)
{
nextButtonAction(ae);
}
});
centerPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
centerPanel.setOpaque(true);
centerPanel.setBackground(Color.WHITE);
centerPanel.setLayout(new GridLayout(0, 2, 5, 5));
centerPanel.add(nameLabel);
centerPanel.add(nameField);
centerPanel.add(addLabel);
centerPanel.add(addField);
centerPanel.add(occLabel);
centerPanel.add(occField);
centerPanel.add(phoneLabel);
centerPanel.add(phoneField);
add(centerPanel, BorderLayout.CENTER);
add(nextButton, BorderLayout.PAGE_END);
}
private void nextButtonAction(ActionEvent ae)
{
CardLayout layout = (CardLayout)contentPane.getLayout();
layout.next(contentPane);
}
}
class SecondCard extends javax.swing.JPanel
{
private javax.swing.JButton nextButton;
private javax.swing.JLabel textLabel;
private JPanel contentPane;
public SecondCard(JPanel cp)
{
contentPane = cp;
initComponents();
}
private void initComponents()
{
setOpaque(true);
setBackground(Color.GREEN.darker().darker());
setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
textLabel = new JLabel("this is the second card", JLabel.CENTER);
textLabel.setForeground(Color.WHITE);
nextButton = new javax.swing.JButton();
nextButton.setText("SwitchCard");
nextButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
jButton1ActionPerformed(evt);
}
});
add(textLabel);
add(nextButton);
}
private void jButton1ActionPerformed(ActionEvent evt)
{
CardLayout layout = (CardLayout) contentPane.getLayout();
layout.show(contentPane, "Panel 1");
}
}
Method to clear fields
private void clearFields()
{
Component components[] = centerPanel.getComponents();
for (Component comp : components)
{
if (comp instanceof JTextField)
{
JTextField tfield = (JTextField) comp;
tfield.setText("");
}
else if (comp instanceof JComboBox)
{
JComboBox cbox = (JComboBox) comp;
cbox.setSelectedIndex(0);
}
else if (comp instanceof JRadioButton)
{
JRadioButton rbut = (JRadioButton) comp;
rbut.setSelected(false);
}
}
}
And you will call this inside the actionPerformed() method of the Button, which will take you to the next Card.
来源：https://stackoverflow.com/questions/13377386/how-to-change-java-cardlayout-from-another-separate-class