java - JCombobox 改变另一个 JCombobox

Question

我正在尝试组合 2 个 jcomboboxes。 1 组合框用于显示费用类别。第二个组合框正在从文本文件中读取文件以显示产品类型。如果我更改第一个组合框，我希望第二个组合框会根据用户在第一个组合框中选择的内容进行更改。

我是否仍然可以从文本文件加载其他组合框？该子项不会是数组，而是与以前相同，因为它位于 cboperson 代码的底部。

编辑代码:

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

例如

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);
    }
}