GridLayoutFrame

[peter huff]

I'm currently trying to understand how GridLayoutFrames work and have got some code from a text book I am working from (from a cd, I didnt type it in so it should be correct), there are two .java files, one, GridLayoutFrame.java does compile however, the other GridLayoutDemo.java does not and I get the following message

GridLayoutDemo.java:9: cannot find symbol
symbol : class gridLayoutFrame
location: class GridLayoutDemo
gridLayoutFrame gridLayoutFrame = new GridLayoutFrame();
^
GridLayoutDemo.java:9: cannot find symbol
symbol : class GridLayoutFrame
location: class GridLayoutDemo
gridLayoutFrame gridLayoutFrame = new GridLayoutFrame();
^
2 errors

does anyone know why this is? if needs be I can post the code. Thanks

[Sunny Kumar]

Originally posted by peter huff:
gridLayoutFrame gridLayoutFrame = new GridLayoutFrame();
^

see the error carefully.
The line in the program should be:
GridLayoutFrame gridLayoutFrame = new GridLayoutFrame();

[peter huff]

i already tried that but it gave me the following message:

GridLayoutDemo.java:9: cannot find symbol
symbol : class GridLayoutFrame
location: class GridLayoutDemo
GridLayoutFrame gridLayoutFrame = new GridLayoutFrame();
^
GridLayoutDemo.java:9: cannot find symbol
symbol : class GridLayoutFrame
location: class GridLayoutDemo
GridLayoutFrame gridLayoutFrame = new GridLayoutFrame();
^
2 errors

[peter huff]

import javax.swing.JFrame;
 
public class GridLayoutDemo 
{
   public static void main( String args[] )
   { 
      gridLayoutFrame gridLayoutFrame = new GridLayoutFrame(); 
      gridLayoutFrame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
      gridLayoutFrame.setSize( 300, 200 ); // set frame size
      gridLayoutFrame.setVisible( true ); // display frame
   } // end main
} // end class GridLayoutDemo    

this is the code as it appears in the book and on the cd there is also the linked code:

   import java.awt.GridLayout;
import java.awt.Container;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;
import javax.swing.JButton;
 
public class GridLayoutFrame extends JFrame implements ActionListener 
{
   private JButton buttons[]; // array of buttons
   private final String names[] = 
      { "one", "two", "three", "four", "five", "six" };
   private boolean toggle = true; // toggle between two layouts
   private Container container; // frame container
   private GridLayout gridLayout1; // first gridlayout
   private GridLayout gridLayout2; // second gridlayout
 
   // no-argument constructor
   public GridLayoutFrame()
   {
      super( "GridLayout Demo" );
      gridLayout1 = new GridLayout( 2, 3, 5, 5 ); // 2 by 3; gaps of 5
      gridLayout2 = new GridLayout( 3, 2 ); // 3 by 2; no gaps
      container = getContentPane(); // get content pane
      setLayout( gridLayout1 ); // set JFrame layout
      buttons = new JButton[ names.length ]; // create array of JButtons
 
      for ( int count = 0; count < names.length; count++ )
      {
         buttons[ count ] = new JButton( names[ count ] );
         buttons[ count ].addActionListener( this ); // register listener
         add( buttons[ count ] ); // add button to JFrame
      } // end for
   } // end GridLayoutFrame constructor
 
   // handle button events by toggling between layouts
   public void actionPerformed( ActionEvent event )
   { 
      if ( toggle )
         container.setLayout( gridLayout2 ); // set layout to second
      else
         container.setLayout( gridLayout1 ); // set layout to first
 
      toggle = !toggle; // set toggle to opposite value
      container.validate(); // re-layout container
   } // end method actionPerformed
} // end class GridLayoutFrame 

[John Wetherbie]

The code as posted generates the following error:

javac GridLayoutDemo.java
GridLayoutDemo.java:7: cannot find symbol
symbol : class gridLayoutFrame
location: class GridLayoutDemo
gridLayoutFrame gridLayoutFrame = new GridLayoutFrame();
^
1 error

As Sunny Kumar noted you need to change the first gridLayoutFrame to GridLayoutFrame. This is because the compiler is looking for a type named gridLayoutFrame and it doesn't exist. Change this to GridLayoutFrame and the classes compile and run fine. You get a window that has six light blue buttons labeled one through six. You click one and the layout changes.

One thing I notice is that you are getting two error messages but you should only be getting one. This implies that even when you fixed the code correctly something else may be preventing the compiler from seeing the GridLayoutFrame class. Maybe there is something messed up in your classpath?
[ January 14, 2006: Message edited by: John Wetherbie ]

[peter huff]

that makes sense that it may be something mucked up in the way |I've set java up. To set the class path i went into control panel-->system-->advanced-->environment variables-->path and then tagged the file directory where the bin is for the jdk. That is right isnt it?

[Larry Reynolds]

Could someone post, or direct me to, the other Java file that goes with the one discussed, I am new to Java and would like to try running these files.

Thanks.

[Nageswar Kakolla]

Hi Peter,

I think you should import GridLayoutFrame into GridLayoutDemo file and that is the reason, Compiler is not able to find GridLayoutFrame Class when GridLayOutDemo is compiled.

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