java - JCombobox change another JCombobox

Question

I'm trying to combine 2 jcomboboxes. 1 combobox is for showing category of expences. and second combobox is reading file from text file to show types of products. If I change first combobox I would like that second combobox will change based on what user select in the first one.

Is there any chance that i can still load the other combobox from text files? That subitems would not be Arrays but same as before as it is on the bottom of the code to cboperson.

edited code:

private JComboBox cboCategory;
private JComboBox cboPerson;
private JComboBox cboItem;
public String itemChange = "groceries.txt";

public ExpenditureTracker() {......


    String[] items = {"Select Item", "Groceries", "Bills", "Travelling", "Leasure", "Other"};
    mainComboBox = new JComboBox(items);
    mainComboBox.addActionListener(this);
    mainComboBox.addItemListener(this);
    //prevent action events from being fired when the up/down arrow keys are used
    //mainComboBox.putClientProperty("JComboBox.isTableCellEditor", Boolean.TRUE);
    mainComboBox.setBounds(113, 138, 85, 20);
    importPanel.add(mainComboBox);


    subComboBox = new JComboBox();//  Create sub combo box with multiple models
    subComboBox.setPrototypeDisplayValue("XXXXXXXXXX"); // JDK1.4
    subComboBox.addItemListener(this);
    subComboBox.setBounds(113, 188, 85, 20);
    importPanel.add(subComboBox);


    String[] subItems1 = {"Select Color", "Red", "Blue", "Green"};
    subItems.put(items[1], subItems1);
    String[] subItems2 = {"Select Shape", "Circle", "Square", "Triangle"};
    subItems.put(items[2], subItems2);
    String[] subItems3 = {"Select Fruit", "Apple", "Orange", "Banana"};
    subItems.put(items[3], subItems3);
    String[] subItems4 = {"Select Fruit", "Apple", "Orange", "Banana"};
    subItems.put(items[4], subItems3);
    String[] subItems5 = {"Select Fruit", "Apple", "Orange", "Banana"};
    subItems.put(items[5], subItems3);


    loadDataTocboPerson();
}




private void loadDataToCboPerson() {
    Scanner fileReader = new Scanner(getClass().getResourceAsStream(
            itemChange));
    try {
        DefaultComboBoxModel model = new DefaultComboBoxModel();
        while (fileReader.hasNextLine()) {
            model.addElement(fileReader.nextLine());
        }
        cboItem.setModel(model);
    } finally {
        fileReader.close();
    }
}

Answer 1

for example

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;

public class ComboBoxTwo extends JFrame implements ActionListener, ItemListener {

    private static final long serialVersionUID = 1L;
    private JComboBox mainComboBox;
    private JComboBox subComboBox;
    private Hashtable<Object, Object> subItems = new Hashtable<Object, Object>();

    public ComboBoxTwo() {
        String[] items = {"Select Item", "Color", "Shape", "Fruit"};
        mainComboBox = new JComboBox(items);
        mainComboBox.addActionListener(this);
        mainComboBox.addItemListener(this);
        //prevent action events from being fired when the up/down arrow keys are used
        //mainComboBox.putClientProperty("JComboBox.isTableCellEditor", Boolean.TRUE);
        getContentPane().add(mainComboBox, BorderLayout.WEST);
        subComboBox = new JComboBox();//  Create sub combo box with multiple models
        subComboBox.setPrototypeDisplayValue("XXXXXXXXXX"); // JDK1.4
        subComboBox.addItemListener(this);
        getContentPane().add(subComboBox, BorderLayout.EAST);
        String[] subItems1 = {"Select Color", "Red", "Blue", "Green"};
        subItems.put(items[1], subItems1);
        String[] subItems2 = {"Select Shape", "Circle", "Square", "Triangle"};
        subItems.put(items[2], subItems2);
        String[] subItems3 = {"Select Fruit", "Apple", "Orange", "Banana"};
        subItems.put(items[3], subItems3);
//      mainComboBox.setSelectedIndex(1);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        String item = (String) mainComboBox.getSelectedItem();
        Object o = subItems.get(item);
        if (o == null) {
            subComboBox.setModel(new DefaultComboBoxModel());
        } else {
            subComboBox.setModel(new DefaultComboBoxModel((String[]) o));
        }
    }

    @Override
    public void itemStateChanged(ItemEvent e) {
        if (e.getStateChange() == ItemEvent.SELECTED) {
            if (e.getSource() == mainComboBox) {
                if (mainComboBox.getSelectedIndex() != 0) {
                    FirstDialog firstDialog = new FirstDialog(ComboBoxTwo.this,
                            mainComboBox.getSelectedItem().toString(), "Please wait,  Searching for ..... ");
                }
            } 
        }
    }

    private class FirstDialog extends JDialog {

        private static final long serialVersionUID = 1L;

        FirstDialog(final Frame parent, String winTitle, String msgString) {
            super(parent, winTitle);
            setModalityType(Dialog.ModalityType.APPLICATION_MODAL);
            JLabel myLabel = new JLabel(msgString);
            JButton bNext = new JButton("Stop Processes");
            add(myLabel, BorderLayout.CENTER);
            add(bNext, BorderLayout.SOUTH);
            bNext.addActionListener(new ActionListener() {

                @Override
                public void actionPerformed(ActionEvent evt) {
                    setVisible(false);
                }
            });
            javax.swing.Timer t = new javax.swing.Timer(1000, new ActionListener() {

                @Override
                public void actionPerformed(ActionEvent e) {
                    setVisible(false);
                }
            });
            t.setRepeats(false);
            t.start();
            setLocationRelativeTo(parent);
            setSize(new Dimension(400, 100));
            setVisible(true);
        }
    }

    public static void main(String[] args) {
        JFrame frame = new ComboBoxTwo();
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}