ShowColors2.java


// Fig. 12.8: ShowColors2.java
// Choosing colors with JColorChooser.
import javax.swing.JFrame;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JColorChooser;
import javax.swing.JPanel;

public class ShowColors2
{
   // execute application
   public static void main( String[] args )
   {
      ShowColors2JFrame application = new ShowColors2JFrame();
      application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
   } // end main
} // end class ShowColors2


class ShowColors2JFrame extends JFrame 
{
   private JButton changeColorJButton;
   private Color color = Color.LIGHT_GRAY;
   private JPanel colorJPanel;

   // set up GUI
   public ShowColors2JFrame()
   {
      super( "Using JColorChooser" );

      // create JPanel for display color
      colorJPanel = new JPanel();
      colorJPanel.setBackground( color );

      // set up changeColorJButton and register its event handler
      changeColorJButton = new JButton( "Change Color" );
      changeColorJButton.addActionListener(

         new ActionListener() // anonymous inner class
         {
            // display JColorChooser when user clicks button
            public void actionPerformed( ActionEvent event )
            {
               color = JColorChooser.showDialog( 
                  ShowColors2JFrame.this, "Choose a color", color );

               // set default color, if no color is returned 
               if ( color == null )
                  color = Color.LIGHT_GRAY;

               // change content pane's background color
               colorJPanel.setBackground( color );
            } // end method actionPerformed
         } // end anonymous inner class
      ); // end call to addActionListener
 
      add( colorJPanel, BorderLayout.CENTER ); // add colorJPanel
      add( changeColorJButton, BorderLayout.SOUTH ); // add button

      setSize( 400, 130 ); // set frame size
      setVisible( true ); // display frame
   } // end ShowColor2JFrame constructor
} // end class ShowColors2JFrame


Results


Maintained by John Loomis, updated Tue May 27 12:32:40 2014