FlowLayout Demo

// Fig. 14.40: FlowLayoutDemo.java
// Testing FlowLayout.

import java.awt.FlowLayout;
import java.awt.Container;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;
import javax.swing.JButton;

class FlowLayoutFrame extends JFrame 
{
   private JButton leftJButton; // button to set alignment left
   private JButton centerJButton; // button to set alignment center
   private JButton rightJButton; // button to set alignment right
   private FlowLayout layout; // layout object
   private Container container; // container to set layout
   
   // set up GUI and register button listeners
   public FlowLayoutFrame()
   {
      super( "FlowLayout Demo" );

      layout = new FlowLayout(); // create FlowLayout
      container = getContentPane(); // get container to layout
      setLayout( layout ); // set frame layout

      // set up leftJButton and register listener
      leftJButton = new JButton( "Left" ); // create Left button
      add( leftJButton ); // add Left button to frame
      leftJButton.addActionListener(

         new ActionListener() // anonymous inner class
         {  
            // process leftJButton event  
            public void actionPerformed( ActionEvent event )
            {
               layout.setAlignment( FlowLayout.LEFT );

               // realign attached components
               layout.layoutContainer( container );
            } // end method actionPerformed
         } // end anonymous inner class
      ); // end call to addActionListener

      // set up centerJButton and register listener
      centerJButton = new JButton( "Center" ); // create Center button
      add( centerJButton ); // add Center button to frame
      centerJButton.addActionListener(

         new ActionListener() // anonymous inner class 
         { 
            // process centerJButton event  
            public void actionPerformed( ActionEvent event )
            {
               layout.setAlignment( FlowLayout.CENTER );

               // realign attached components
               layout.layoutContainer( container );
            } // end method actionPerformed
         } // end anonymous inner class
      ); // end call to addActionListener

      // set up rightJButton and register listener
      rightJButton = new JButton( "Right" ); // create Right button
      add( rightJButton ); // add Right button to frame
      rightJButton.addActionListener(

         new ActionListener() // anonymous inner class
         {  
            // process rightJButton event  
            public void actionPerformed( ActionEvent event )
            {
               layout.setAlignment( FlowLayout.RIGHT );

               // realign attached components
               layout.layoutContainer( container );
            } // end method actionPerformed
         } // end anonymous inner class
      ); // end call to addActionListener
   } // end FlowLayoutFrame constructor
} // end class FlowLayoutFrame


public class FlowLayoutDemo 
{
   public static void main( String[] args )
   { 
      FlowLayoutFrame flowLayoutFrame = new FlowLayoutFrame(); 
      flowLayoutFrame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
      flowLayoutFrame.setSize( 300, 75 ); // set frame size
      flowLayoutFrame.setVisible( true ); // display frame
   } // end main
} // end class FlowLayoutDemo