package Layout;
// Fig. 14.19: GridBagDemo.java
// Demonstrating GridBagLayout.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class GridBagDemo extends JFrame { 
   private Container container;
   private GridBagLayout layout;
   private GridBagConstraints constraints; 
    
   // set up GUI
   public GridBagDemo()
   {
      super( "GridBagLayout" );

      container = getContentPane();
      layout = new GridBagLayout();
      container.setLayout( layout );   

      // instantiate gridbag constraints
      constraints = new GridBagConstraints();

      // create GUI components
      JTextArea textArea1 = new JTextArea( "TextArea1", 5, 10 );
      JTextArea textArea2 = new JTextArea( "TextArea2", 2, 2 );

      String names[] = { "Iron", "Steel", "Brass" };
      JComboBox comboBox = new JComboBox( names );

      JTextField textField = new JTextField( "TextField" );
      JButton button1 = new JButton( "Button 1" );
      JButton button2 = new JButton( "Button 2" );
      JButton button3 = new JButton( "Button 3" );

      // weightx and weighty for textArea1 are both 0: the default
      // anchor for all components is CENTER: the default
      constraints.fill = GridBagConstraints.BOTH;
      addComponent( textArea1, 0, 0, 1, 3 );    
       
      // weightx and weighty for button1 are both 0: the default
      constraints.fill = GridBagConstraints.HORIZONTAL;
      addComponent( button1, 0, 1, 2, 1 );
      
      // weightx and weighty for comboBox are both 0: the default
      // fill is HORIZONTAL
      addComponent( comboBox, 2, 1, 2, 1 );             

      // button2
      constraints.weightx = 1000;  // can grow wider
      constraints.weighty = 1;     // can grow taller
      constraints.fill = GridBagConstraints.BOTH;
      addComponent( button2, 1, 1, 1, 1 );
       
      // fill is BOTH for button3
      constraints.weightx = 0;
      constraints.weighty = 0;    
      addComponent( button3, 1, 2, 1, 1 );
       
      // weightx and weighty for textField are both 0, fill is BOTH
      addComponent( textField, 3, 0, 2, 1 );

      // weightx and weighty for textArea2 are both 0, fill is BOTH
      addComponent( textArea2, 3, 2, 1, 1 );

      setSize( 300, 150 );
      setVisible( true );

   } // end constructor GridBagDemo

   // method to set constraints on 
   private void addComponent( Component component,
      int row, int column, int width, int height )
   {
      // set gridx and gridy 
      constraints.gridx = column;
      constraints.gridy = row;

      // set gridwidth and gridheight
      constraints.gridwidth = width;   
      constraints.gridheight = height;

      // set constraints and add component
      layout.setConstraints( component, constraints );  
      container.add( component );      
   }

   public static void main( String args[] )
   {
      GridBagDemo application = new GridBagDemo();
      application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
   }

} // end class GridBagDemo
