java - 如何使 JCombobox 具有更改其他 JCombobox 上的项目的功能

Question

我的转换器程序中有 3 个 JCombobox，其中一个用于类别，两个用于选择要执行的功能；我希望程序做的是，当用户在一个 JCombobox 中选择一个类别时，两个 JCombobox 将自动更改与所选类别相关的内容(请帮助我使用 JCombobox 更改项目的功能，当选择一个类别时，其他更改值)；

Answer 1

如JB Nizet说，这是一个简短的例子:

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;


public class ConnectedComboBoxDemo extends JFrame implements ActionListener {

    private static final long serialVersionUID = 6108579736224814080L;

    private JPanel panel;
    private JComboBox combo1;
    private JComboBox combo2;

    public ConnectedComboBoxDemo() {
        panel = new JPanel();
        String[] combo1Item = new String[]{"val1", "val2", "val3"};
        combo1 = new JComboBox(combo1Item);
        combo1.addActionListener(this);

        String[] combo2Item = new String[]{"val11", "val12", "val13"};
        combo2 = new JComboBox(combo2Item);

        panel.setLayout(new BorderLayout());
        panel.add(combo1, BorderLayout.WEST);
        panel.add(combo2, BorderLayout.EAST);

        setContentPane(panel);
        pack();
        setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        String selectedValue = combo1.getSelectedItem().toString();
        String[] combo2Item = null;

        DefaultComboBoxModel model = (DefaultComboBoxModel) combo2.getModel();      
        model.removeAllElements();

        if(selectedValue.equals("val1")){
            combo2Item = new String[]{"val11", "val12", "val13"};
        } else if(selectedValue.equals("val2")){
            combo2Item = new String[]{"val21", "val22", "val23"};
        } else if(selectedValue.equals("val3")){
            combo2Item = new String[]{"val31", "val32", "val33"};
        }

        for(String val : combo2Item){
            model.addElement(val);
        }
    }   

    public static void main(String... args){
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new ConnectedComboBoxDemo();
            }
        });
    }
}

希望这对您有帮助。