flowlayoutdemo.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. 29.17: FlowLayoutDemo.java
// Demonstrating FlowLayout alignments.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class FlowLayoutDemo extends JFrame {
   private JButton left, center, right;
   private Container c;
   private FlowLayout layout;
   
   public FlowLayoutDemo()
   {
      super( "FlowLayout Demo" );

      layout = new FlowLayout();

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

      left = new JButton( "Left" );
      left.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               layout.setAlignment( FlowLayout.LEFT );

               // re-align attached components
               layout.layoutContainer( c );
            }
         }
      );
      c.add( left );

      center = new JButton( "Center" );
      center.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               layout.setAlignment( FlowLayout.CENTER );

               // re-align attached components
               layout.layoutContainer( c );  
            }
         }
      );
      c.add( center );

      right = new JButton( "Right" );
      right.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               layout.setAlignment( FlowLayout.RIGHT );

               // re-align attached components
               layout.layoutContainer( c );  
            }
         }
      );
      c.add( right );

      setSize( 300, 75 );
      show();
   }

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

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

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