Best way to change GUI on the fly

Question

Scenario :
A program has a simple GUI, subclassing JFrame with a JPanel content pane. Initially the GUI is a simple few text fields and a JButton. Now for the part that eludes me, when the JButton is clicked the GUI should be replaced by a graph drawn from information in the text fields.
Coding a custom subclass of JComponent to handle the graphing is not a problem but the step to remove the text fields and JButton eludes me. What options are there and what pro/cons do they have?
Cheers

Answer 1

when you update layouts in any way, you need to call the container of the GUI's validate() method. this will ensure everything is where it needs to be. to change your gui over to your graph, it's a good idea to remove eevrything from the current GUI, add the graph, and then call the validate method. I'm really bored so I wrote you a simple example:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Graph extends JPanel {
     int y[]; // y-axis (inputted)
     int x[]; // x-axis (computed)
     public Graph(int y[]) {
          this.y = y;
          x = new int[y.length];
          setBackground(Color.white);
     public void paintComponent(Graphics g) {
          super.paintComponent(g);
          int n = 0;
          for (int j = 0;j < x.length;j++) {
               x[j] = n;
               n+=(getWidth()/x.length);
          g.setColor(Color.blue);
          g.drawPolyline(x,y,x.length);
public class Example extends JFrame implements ActionListener {
     JTextField text[]; // input fields
     JButton button;
     JLabel label[];
     public Example() {
          super("Example");
          Container c = getContentPane();
          c.setLayout(new GridLayout(0,2));
          setDefaultCloseOperation(EXIT_ON_CLOSE);
          text = new JTextField[10];
          label = new JLabel[text.length];
          // below is default GUI setup
          for (int j = 0;j < text.length;j++) {
               label[j] = new JLabel("Y value #"+(j+1)+": ");
               text[j] = new JTextField();
               c.add(label[j]);
               c.add(text[j]);
          button = new JButton("Graph!");
          c.add(button);
          button.addActionListener(this);
          pack();
          setSize(new Dimension(400,getHeight()));
          show();
     public void actionPerformed(ActionEvent e) {
          if (e.getSource() == button) {
               int j;
               int y[] = new int[text.length];
               for (j = 0;j < y.length;j++) {
                    try {
                         y[j] = Integer.parseInt(text[j].getText());
                    catch (NumberFormatException ne) {
                         // one of the fields isnt an
                         // acceptable number, so forget about it
                         return;
               // here the GUI needs to be rebuilt
               Container c = getContentPane();
               for (j = 0;j < text.length;j++) {
                    c.remove(text[j]);
                    c.remove(label[j]);
               c.remove(button);
               c.setLayout(new BorderLayout());
               c.add(new Graph(y),BorderLayout.CENTER);
               c.validate(); // <-- that is the key method to update the GUI
     public static void main(String args[]) {
          new Example();
}