import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class ShowNoLayout extends Applet {

  private Label lbl = new Label("ShowNoLayout");
  private TextArea ta1 = new TextArea("Text Area", 5, 10 );
  private TextArea ta2 = new TextArea("Text Area", 5, 10 );
  private TextField tf = new TextField("TextField");
  private Panel p = new Panel();
  private Button bt1 = new Button("Cancel" );
  private Button bt2 = new Button("Ok" );

  public void init() {

    setSize(400,200);

    // Specify no layout manager
    setLayout(null);

    // Set background color for the panel
    p.setBackground(Color.red);

    // Put componets in the right place
    lbl.setBounds(0, 10, 400, 40);
    ta1.setBounds(0, 50, 100, 100);
    p.setBounds(100, 50, 200, 100);
    ta2.setBounds(300, 50, 100, 50);
    tf.setBounds(300, 100, 100, 50);
    bt1.setBounds(100, 150, 100, 50);
    bt2.setBounds(200, 150, 100, 50);

    // Add components to Panel
    add(lbl);
    add(p);
    add(ta1);
    add(ta2);
    add(tf);
    add(bt1);
    add(bt2);
  }
}

• divides the container into grid

• Label
  Text Area 1	Panel	Text Area 2
  		Text Field
  	Button 1	Button 2

• a component can vary in size and added in any order
• use GridBagConstraints to specify how the component is laid out within its display area
• the addComp() method

  private void addComp(Component c, GridBagLayout gbLayout,
                         GridBagConstraints gbConstraints,
                         int row, int column, int numRows,
                         int numColumns, int weightx, int weighty) 
  

  gbConstraints.gridx = column

  column in which the component will be placed

  gbConstraints.gridy = row

  row in which the component will be placed

  gbConstraints.gridwidth = numColumns

  number of columns occupied

  gbConstraints.gridheight = numRows

  number of rows occupied

  gbConstraints.weightx = weightx

  specifies how to distribute extra horizontal space to become wider

  gbConstraints.weighty = weighty

  specifies how to distribute extra vertical space to become taller

• gbConstraints.fill

  specifies how to resize component if display area is larger than its current size

  GridBagConstraints.BOTH

  wider and taller to fill the display area completely

  gbConstraints.anchor

  specifies how to place the component

  GridBagConstraints.CENTER

  place in the center

• ShowGridBagLayout using 400X200 size panel
  
• ShowGridBagLayout using 300X300 size panel
  
• ShowGridBagLayout using 640X480 size panel
  

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class ShowGridBagLayout extends Applet {

  private Label lbl;
  private TextArea ta1, ta2;
  private TextField tf;
  private Panel p;
  private Button bt1, bt2;
  private GridBagLayout gbLayout;
  private GridBagConstraints gbConstraints;

  // Add a component to the container
  private void addComp(Component c, GridBagLayout gbLayout,
                       GridBagConstraints gbConstraints,
                       int row, int column, int numRows,
                       int numColumns, int weightx, int weighty) {

    // Set parameters
    gbConstraints.gridx = column;
    gbConstraints.gridy = row;
    gbConstraints.gridwidth = numColumns;
    gbConstraints.gridheight = numRows;
    gbConstraints.weightx = weightx;
    gbConstraints.weighty = weighty;

    // Set constraints in the GridBagLayout
    gbLayout.setConstraints(c, gbConstraints);

    // Add component to the container
    add(c);
  }

  // Constructor
  public void init() {

    // Initialize GUI components
    lbl = new Label("ShowGridBagLayout");
    p = new Panel();
    ta1 = new TextArea("Text Area", 5, 15 );
    ta2 = new TextArea("Text Area", 5, 15 );
    tf = new TextField("TextField");
    bt1 = new Button("Cancel" );
    bt2 = new Button("Ok" );

    // Create GridBagLayout and GridBagConstraints object
    gbLayout = new GridBagLayout();
    gbConstraints = new GridBagConstraints();
    setLayout(gbLayout);

    // Place Label to occupy row 0 (the first row)
    gbConstraints.fill = GridBagConstraints.BOTH;
    gbConstraints.anchor = GridBagConstraints.CENTER;
    addComp(lbl, gbLayout, gbConstraints, 0, 0, 1, 4, 0, 0);

    // Place text area 1 in row 1 and 2, and column 0
    addComp(ta1, gbLayout, gbConstraints, 1, 0, 2, 1, 0, 0);

    // Place Panel in row 1 and 2, and column 1 and 2
    addComp(p, gbLayout, gbConstraints, 1, 1, 2, 2, 100, 100);
    p.setBackground(Color.red);

    // Place text area 2 in row 1 and column 3
    addComp(ta2, gbLayout, gbConstraints, 1, 3, 1, 1, 0, 100);

    // Place text field in row 2 and column 3
    addComp(tf, gbLayout, gbConstraints, 2, 3, 1, 1, 0, 0);

    // Place Button 1 in row 3 and column 1
    addComp(bt1, gbLayout, gbConstraints, 3, 1, 1, 1, 0, 0);

    // Place JButton 2 in row 3 and column 2
    addComp(bt2, gbLayout, gbConstraints, 3, 2, 1, 1, 0, 0);
  }
}