Add Swing Components Dynamically using Array List

Below code is to add swing components (button and textfield) dynamically using ArrayList.


import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JRootPane;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class ButtonAddDynamic implements ActionListener{

public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new ButtonAddDynamic().createAndShowGUI();
}
});
}

private JFrame frame;
private JPanel panel = new JPanel(new GridBagLayout());
private GridBagConstraints constraints = new GridBagConstraints();

private List fields = new ArrayList();
private List fieldButton = new ArrayList();
private List fieldFile = new ArrayList();

private JButton button1 = new JButton("Add Another TextField and Button");
private static int countReport = 0;
String files = null;
int y=2;

protected void createAndShowGUI() {
try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
} catch (UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
} catch (InstantiationException ex) {
ex.printStackTrace();
} catch (ClassNotFoundException ex) {
ex.printStackTrace();
} catch (IllegalAccessException ex) {
ex.printStackTrace();
}

String[] labels = { "Locations of the given input" };
for (String label : labels)
addColumn(label);
addRowBelow();
constraints.gridx=1;
constraints.gridy=0;
panel.add(button1,constraints);

frame = new JFrame("Add Button Dynamically");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new JScrollPane(panel));
frame.setLocationRelativeTo(null);
frame.setResizable(false);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
button1.addActionListener(this);

//Set the default button to button1, so that when return is hit, it will hit the button1

JRootPane root = frame.getRootPane();
root.setDefaultButton(button1);
frame.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent we){
System.exit(0);
}
});
}


private void addColumn(String labelText) {
constraints.gridx = fields.size();
constraints.gridy = 1;
panel.add(new JLabel(labelText), constraints);
constraints.gridy=2;
final JTextField field=new JTextField(40);
field.setEditable(false);
panel.add(field,constraints);
fields.add(field);

//constraints.gridy=3;
constraints.gridx = fields.size() + fieldButton.size();
JButton button = new JButton("OK");
button.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae){
JOptionPane.showMessageDialog(null,"Program to add swing components dynamically","HI",1);
}
}
);
panel.add(button,constraints);
fieldButton.add(button);
panel.revalidate(); // redo layout for extra column
}


private void addRowBelow() {
y++;
constraints.gridy=y;
//System.out.println(fields.size());
for (int x=0;x < fields.size();x++) {
constraints.gridx=x;
final JTextField field = new JTextField(40);
field.setEditable(false);
panel.add(field, constraints);
constraints.gridx=x+1;
JButton button = new JButton("OK");
button.addActionListener(new ActionListener()
{ public void actionPerformed(ActionEvent ae){
JOptionPane.showMessageDialog(null,"Program to add swing components dynamically","HI",1);
}
}
);
panel.add(button,constraints);
}
}

public void actionPerformed(ActionEvent ae){
if("Add Another TextField and Button".equals(ae.getActionCommand())) {
addRowBelow();
frame.pack();
frame.setLocationRelativeTo(null);
}
}
}