gridlayoutdemo.java

经典的<<C how to program>一书第三版的例程。非常适合于C的初学者。

// Fig. 29.19: GridLayoutDemo.java
// Demonstrating GridLayout.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class GridLayoutDemo extends JFrame
                            implements ActionListener {
   private JButton b[];
   private String names[] =
      { "one", "two", "three", "four", "five", "six" };
   private boolean toggle = true;
   private Container c;
   private GridLayout grid1, grid2;

   public GridLayoutDemo()
   {
      super( "GridLayout Demo" );

      grid1 = new GridLayout( 2, 3, 5, 5 );
      grid2 = new GridLayout( 3, 2 );

      c = getContentPane();
      c.setLayout( grid1 );

      // create and add buttons
      b = new JButton[ names.length ];

      for (int i = 0; i < names.length; i++ ) {
         b[ i ] = new JButton( names[ i ] );
         b[ i ].addActionListener( this );
         c.add( b[ i ] );
      }

      setSize( 300, 150 );
      show();
   }

   public void actionPerformed( ActionEvent e )
   { 
      if ( toggle )
         c.setLayout( grid2 );
      else
         c.setLayout( grid1 );

      toggle = !toggle;
      c.validate();
   }

   public static void main( String args[] )
   {
      GridLayoutDemo app = new GridLayoutDemo();

      app.addWindowListener(
         new WindowAdapter() {
            public void windowClosing( WindowEvent e )
            {
               System.exit( 0 );
            }
         }
      );
   } 
}

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 * (C) Copyright 2000 by Deitel & Associates, Inc. and Prentice Hall.     *
 * All Rights Reserved.                                                   *
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 * development, research, and testing of the theories and programs        *
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