JPanel cannot be resolved?

[JamieEdwards]

Hi guys,

I've hit a problem with an unusual error:

addCustPanel Cannot be resolved.

The really annoying thing is that I designed this in netbeans first and it worked perfectly fine, I also opened the netbeans java file with "addCustPanel" in it in Eclipse and there are no resolve error in that, so what is going on?

The file is so long, some 316 lines, I've pasted it to pastebin:
custInfoGUI.java

The error is on line 306.

Any ideas on what is wrong with Eclipse and how I could get about fixing it?

Thanks.

[jim829]

There is nothing wrong with Eclipse. You declared your variables in a method so their scope is limited to that method. Other methods can't see them.
If this worked in NetBeans then the problem is with NetBeans.

And BTW, it is bad technique to extend JFrame. Just create an instance. If you need to do some drawing or layout, extend JPanel and add to JFrame.

Regards,
Jim

[JamieEdwards]

I opened up the same file in Eclipse again ( From netbeans ) and the red squiggle didn't appear?

Also how would I be able to create the new instance of JFrame and implement it into the code I posted?

[jim829]

Your program should not compile as written.

You have the following in one method.

private void initComponents() {
        GridBagConstraints gridBagConstraints;
        
        // Define new Components
        
        // The buttons:
        JButton addCustButton     = new JButton ( "Add Customer" );
        JButton findCustButton     = new JButton ( "Find Customer" );
        JButton backButton        = new JButton ( "Back" );
        JButton submitButton    = new JButton ( "Submit" );
        // The panels:
        JPanel addCustPanel        = new JPanel();
         ...
}

And the following in another.

private void addCustButtonActionPerformed ( ActionEvent e ) {
        addCustPanel.setVisible ( true );
}

The scope of addCustPanel is declared in (and hence local to) the initComponents method. It is not visible to the addCustButtonActionPerformed method.

Regards,
Jim

[JamieEdwards]

So what would be the best solution because I want to be able to have that panel appear when addCustButton is pressed?

[JamieEdwards]

OK, I feel a little stupid as I've just realised and seen what Netbeans has done, and that's that it added variable prototypes at the very bottom of the main class ( which should be global ( if Java is as similar to C++ as I know ) ) allowing me to use it anywhere?

[jim829]

You need to declare your instance fields in the top level portion of the class, not in any method. That way, they will be visible to all other methods of the enclosing class. Any variables declared within a method are of local scope to that method only.

Regards,
Jim

[JamieEdwards]

Ah, I get it now... Another problem has occurred with the JFrame ( or atleast I think it is... )

I put the following into the main function:

EventQueue.invokeLater ( new Runnable() {
    public void run() {
        new MainGUI().setVisible ( true );
    }
} );

And it has the following error:

The Method setVisible(boolean) is undefined for the type MainGUI

NB. This is from a different project, but is structured EXACTLY the same as the one stated in the OP :L but the OP works perfectly fine... :S

[jim829]

If the MainGUI class doesn't declare a setVisible method or inherit a class that does, you would get that message.

Regards,
Jim

[JamieEdwards]

How do I go about doing that then? :L

[jim829]

What does your MainGUI class look like? It makes no sense to create a setVisible method unless it can be somehow applied (like self painting).

Regards,
Jim

[JamieEdwards]

see the pastebin link below, it's easier if I paste the main.java file so you can see it for yourself...

main.java

[jim829]

You can't invoke setVisible from an instance of Main because Main doesn't extend anything or implement that method. However, in your program you
create an instance of JFrame called mainframe. After you invoke mainframe.pack(), then do mainframe.setVisible(true).

Regards,
Jim