how to Save a jpanel containing combo-boxes and text-boxes in java netbeans?

Question

I am creating an application which helps solving problems of an accounting book. The application has 12 chapters. All chapters contains 15-20 problems. The problem is displayed in a JPanel containing various combo-boxes and formatted-text boxes. suppose i solved a problem half and want to save so that next time i can load that half solved question.

Saving should be done by clicking save from menubar. And loading by load from the menubar

All menubars and problem sheet are working but i am not able to save any thing. I was using jFilechooser...

Is their any way to do that?

How to save a panel with filled combo-boxes items and text-boxes. And is their any way to know that user has made any changes in any items so that on closing the problem i can again ask to save it first and then exit.

Thanks in advance.

Some of my codes:

private void openBtnMouseClicked(java.awt.event.MouseEvent evt) {
opening();
}
public void opening() {
        JFileChooser chooser=new JFileChooser();
        int choice=chooser.showOpenDialog(this);       
        javax.swing.JComboBox[] sourceALE = {aaCombo, baCombo, caCombo, daCombo, eaCombo, faCombo, gaCombo, haCombo, iaCombo, jaCombo, kaCombo,
                            alCombo, blCombo, clCombo, dlCombo, elCombo, flCombo, glCombo, hlCombo, ilCombo, jlCombo, klCombo,
                            aeCombo, beCombo, ceCombo, deCombo, eeCombo, feCombo, geCombo, heCombo, ieCombo, jeCombo, keCombo};
                            javax.swing.JTextField[] sourceP = {aeval1, beval, ceval, deval, eeval, feval, geval, heval, ieval, jeval, keval};
                           String [] comboboxes={"aaCombo", "baCombo", "caCombo", "daCombo", "eaCombo", "faCombo", "gaCombo", "haCombo", "iaCombo", "jaCombo", "kaCombo","alCombo", "blCombo", "clCombo", "dlCombo", "elCombo", "flCombo", "glCombo", "hlCombo", "ilCombo", "jlCombo","klCombo","aeCombo", "beCombo", "ceCombo", "deCombo", "eeCombo", "feCombo", "geCombo", "heCombo", "ieCombo", "jeCombo", "keCombo"};
        if(choice==JFileChooser.APPROVE_OPTION) {

            File file = chooser.getSelectedFile();
            try {
                System.out.println("Hey");
                Scanner scanner = new Scanner(new FileReader(file));
                while ( scanner.hasNextLine() ){
                    Scanner scan = new Scanner(scanner.nextLine());
                    scan.useDelimiter("=");
                    if ( scan.hasNext() ){
                        String item=scan.next();
                        int value=scan.nextInt();
                        String color=scan.next();
                        for(int g=0;g<comboboxes.length;g++){
                            if(item.equals(comboboxes[g])) {
                                if(value<3)
                                sourceALE[g].setSelectedIndex(value);
                                if(color.equals("red"))
                                sourceALE[g].setForeground(red);
                                if(color.equals("green"))
                                sourceALE[g].setForeground(green);
                                if(color.equals("blah"))
                                sourceALE[g].setForeground(blah);
                            }
                        }
                    }
                    scan.close();
                }
                scanner.close();
            } catch (FileNotFoundException ex) {
                Logger.getLogger(q1.class.getName()).log(Level.SEVERE, null, ex);
            }
                }
                public void opening() {
        JFileChooser chooser=new JFileChooser();
        int choice=chooser.showOpenDialog(this);       
        javax.swing.JComboBox[] sourceALE = {aaCombo, baCombo, caCombo, daCombo, eaCombo, faCombo, gaCombo, haCombo, iaCombo, jaCombo, kaCombo,
                            alCombo, blCombo, clCombo, dlCombo, elCombo, flCombo, glCombo, hlCombo, ilCombo, jlCombo, klCombo,
                            aeCombo, beCombo, ceCombo, deCombo, eeCombo, feCombo, geCombo, heCombo, ieCombo, jeCombo, keCombo};
                            javax.swing.JTextField[] sourceP = {aeval1, beval, ceval, deval, eeval, feval, geval, heval, ieval, jeval, keval};
                           String [] comboboxes={"aaCombo", "baCombo", "caCombo", "daCombo", "eaCombo", "faCombo", "gaCombo", "haCombo", "iaCombo", "jaCombo", "kaCombo","alCombo", "blCombo", "clCombo", "dlCombo", "elCombo", "flCombo", "glCombo", "hlCombo", "ilCombo", "jlCombo","klCombo","aeCombo", "beCombo", "ceCombo", "deCombo", "eeCombo", "feCombo", "geCombo", "heCombo", "ieCombo", "jeCombo", "keCombo"};
        if(choice==JFileChooser.APPROVE_OPTION) {

            File file = chooser.getSelectedFile();
            try {
                System.out.println("Hey");
                Scanner scanner = new Scanner(new FileReader(file));
                while ( scanner.hasNextLine() ){
                    Scanner scan = new Scanner(scanner.nextLine());
                    scan.useDelimiter("=");
                    if ( scan.hasNext() ){
                        String item=scan.next();
                        int value=scan.nextInt();
                        String color=scan.next();
                        for(int g=0;g<comboboxes.length;g++){
                            if(item.equals(comboboxes[g])) {
                                if(value<3)
                                sourceALE[g].setSelectedIndex(value);
                                if(color.equals("red"))
                                sourceALE[g].setForeground(red);
                                if(color.equals("green"))
                                sourceALE[g].setForeground(green);
                                if(color.equals("blah"))
                                sourceALE[g].setForeground(blah);
                            }
                        }
                    }
                    scan.close();
                }
                scanner.close();
            } catch (FileNotFoundException ex) {
                Logger.getLogger(q1.class.getName()).log(Level.SEVERE, null, ex);
            }
                }
        System.out.println("OUT");
            }
            }

Answer 1

I have to wonder if you've created this program primarily as a NetBeans-generated GUI without first creating the non-GUI guts of the program. So first I have to ask, have you divided out your program logic from your GUI code a la MVC (model-view-controller) or one of its many variants? If not then this should be your first order of business, since in truth the saving and recovery of the data should have nothing to do with its GUI representation.

The key to solving your problem is going to be good object-oriented programming design. Consider for instance creating a non-GUI Question class that has several fields including a String question field, an ArrayList of possibleAnswers and a field String for the correctAnswer. Consider having an ArrayList of these Questions (ArrayList) for each chapter and a collection of the Chapters. Then you will need to figure out the best way for you to save the questions and the users answers. This may be via serialization, XML (JAXB?), or my recommendation: a database.

Only after you've figured out all of this should you worry about how to integrate a GUI around your non-GUI logic code which will be the GUI's "model".

Edit
Replies to your comments:

Sorry i havent provided enough info of my project. I m doing it in NETBEANS 7 GUI.I guess netbeans java programs are MVC

Sorry, no. If all you do is create a GUI with NetBeans you will be creating an unwieldy god-class. To have good MVC you must design it that way from the beginning. Again that means creating your program logic before creating the GUI which in your case includes creating multiple non-GUI classes as I've indicated above. There is no "automatic" MVC in NetBeans.

I may be wrong as i dont know much about MVC.

Yes, unfortunately you're wrong. Please read about it: Model-View-Controller. This will help you with your current and future design.

As of now i am able to save and retrieve. But i want your suggestion on that. It is quite hardcoded for each question.

And that should probably be fixed as you do not be hard-coding the questions. In fact the question text shouldn't even be part of the code but part of the data. Consider having the question in a comma-delimited text file or database.

i tried to answer 5 components and save it in notepad. And on loading it i am able to get all those components filled. Its working. But its quite hard coded and yes of course bad programming. But i have some time limitations so can you suggest anything similar to this logic. if by some function or method i could know all the components variable name present in my JPanel. like all the 15-20 combo-box and same no of text-box. I could make a function which can be common for all

Sorry, I wish I could, but I can't, not unless you first fix your design issues. Good luck!

Answer 2

1) It is good design to separate your data from the presentation. Are you doing this already? What I mean is you should be looking to store answers in an object outside of the jPanel class. (As 'Hovercraft Full Of Eels' suggested)

2) Consider making the data objects Serializable objects. If you're not planning on storing the data across a network or anything complicated/peculiar this should work out for you as it will facilitate save/load operations

3) Once you have your data separate from the GUI a check for changes becomes very easy. Assume that on any operation that takes you away from the page it "saves" its state. If the current state is different from the saved state then prompt the user to save (if it doesn't by default)