The JPanel class resides in the package javax.swing and it’s a subclass of the javax.swing.JComponent class.
JPanel newPanel = new JPanel();That creates a new JPanel with double enabled by default.
public class UserDetail extends JPanel { // code to add components to the panel }
JPanel newPanel = new JPanel(true); // enable double buffering JPanel newPanel = new JPanel(false); // disable double buffering
JPanel newPanel = new JPanel(new GridBagLayout()); JPanel newPanel = new JPanel(new BorderLayout());By default, the panel has a flow layout manager.
// use grid bag layout and no double buffering: JPanel newPanel = new JPanel(new GridBagLayout(), false);
JPanel newPanel = new JPanel(); newPanel.setLayout(new GridBagLayout());
// NOT recommended: JPanel newPanel = new JPanel(); // a FlowLayout manager is created by default newPanel.setLayout(new GridBagLayout()); // RECOMMENDED: JPanel newPanel = new JPanel(new GridBagLayout());
// exception: JPanel newPanel = new JPanel(); newPanel.setLayout(new BoxLayout(newPanel, BoxLayout.X_AXIS));
JLabel label = new JLabel("Enter username:"); JTextField userName = new JTextField(20); newPanel.add(label); newPanel.add(userName);
JPanel newPanel = new JPanel(new BorderLayout()); JLabel label = new JLabel("Enter username:"); JTextField userName = new JTextField(20); newPanel.add(label, BorderLayout.NORTH); newPanel.add(userName, BorderLayout.SOUTH);
GridBagConstraints constraints = new GridBagConstraints(); constraints.anchor = GridBagConstraints.WEST; constraints.insets = new Insets(10, 10, 10, 10); constraints.gridx = 0; constraints.gridy = 0; newPanel.add(labelUsername, constraints);
JPanel wizardPanel = new JPanel(new CardLayout()); wizardPanel.add("Step1", step1Panel); wizardPanel.add("Step2", step2Panel);
frame.add(newPanel); anotherPanel.add(newPanel);
newPanel.setBackground(Color.CYAN);
newPanel.setOpaque(false); // make transparent background
newPanel.setBorder(BorderFactory.createBevelBorder(BevelBorder.RAISED));
newPanel.setBorder(BorderFactory.createEtchedBorder());
newPanel.setBorder(BorderFactory.createLineBorder(Color.RED));
newPanel.setBorder(BorderFactory.createTitledBorder( BorderFactory.createEtchedBorder(), "Login Panel"));
package net.codejava.swing.jpanel; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.Insets; import javax.swing.BorderFactory; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JPasswordField; import javax.swing.JTextField; import javax.swing.SwingUtilities; import javax.swing.UIManager; /** * This program demonstrates how to use JPanel in Swing. * @author www.codejava.net */ public class SwingJPanelDemo extends JFrame { private JLabel labelUsername = new JLabel("Enter username: "); private JLabel labelPassword = new JLabel("Enter password: "); private JTextField textUsername = new JTextField(20); private JPasswordField fieldPassword = new JPasswordField(20); private JButton buttonLogin = new JButton("Login"); public SwingJPanelDemo() { super("JPanel Demo Program"); // create a new panel with GridBagLayout manager JPanel newPanel = new JPanel(new GridBagLayout()); GridBagConstraints constraints = new GridBagConstraints(); constraints.anchor = GridBagConstraints.WEST; constraints.insets = new Insets(10, 10, 10, 10); // add components to the panel constraints.gridx = 0; constraints.gridy = 0; newPanel.add(labelUsername, constraints); constraints.gridx = 1; newPanel.add(textUsername, constraints); constraints.gridx = 0; constraints.gridy = 1; newPanel.add(labelPassword, constraints); constraints.gridx = 1; newPanel.add(fieldPassword, constraints); constraints.gridx = 0; constraints.gridy = 2; constraints.gridwidth = 2; constraints.anchor = GridBagConstraints.CENTER; newPanel.add(buttonLogin, constraints); // set border for the panel newPanel.setBorder(BorderFactory.createTitledBorder( BorderFactory.createEtchedBorder(), "Login Panel")); // add the panel to this frame add(newPanel); pack(); setLocationRelativeTo(null); } public static void main(String[] args) { // set look and feel to the system look and feel try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (Exception ex) { ex.printStackTrace(); } SwingUtilities.invokeLater(new Runnable() { @Override public void run() { new SwingJPanelDemo().setVisible(true); } }); } }You can download the code as well as an executable jar file of this program in the attachments section.