组合框seteditable(true)

组合框的setEditable(boolean)方法用于设置组合框是否可编辑。如果将其设置为true，则用户可以在组合框中输入文本。如果设置为false，则用户只能从下拉列表中选择预定义的选项。

例如，以下代码将创建一个组合框并将其设置为可编辑：

JComboBox<String> comboBox = new JComboBox<>();
comboBox.setEditable(true);

这将创建一个空的组合框，允许用户输入自己的文本。

相关问题

Java编写类Example05，创建JPanel面板；创建一个组合框并为组合框添加选项；为组合框添加事件监听器，所选择的组合框内容会显示在文本框中。

好的，下面是实现您所需功能的Java代码：

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class Example05 extends JFrame implements ActionListener {
    private static final long serialVersionUID = 1L;
    private JPanel panel;
    private JComboBox<String> comboBox;
    private JTextField textField;

    public Example05() {
        setTitle("组合框示例");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        panel = new JPanel(new BorderLayout());

        comboBox = new JComboBox<String>();
        comboBox.addItem("选项1");
        comboBox.addItem("选项2");
        comboBox.addItem("选项3");
        comboBox.addActionListener(this);

        textField = new JTextField();
        textField.setEditable(false);

        panel.add(comboBox, BorderLayout.NORTH);
        panel.add(textField, BorderLayout.CENTER);

        getContentPane().add(panel);
        pack();
        setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == comboBox) {
            String selected = (String) comboBox.getSelectedItem();
            textField.setText(selected);
        }
    }

    public static void main(String[] args) {
        new Example05();
    }
}

在上述代码中，我们创建了一个JPanel面板，并在面板上添加了一个JComboBox组合框和一个JTextField文本框。我们为组合框添加了三个选项，并使用addActionListener方法为组合框添加了事件监听器，在监听器中获取用户选择的选项，并将其显示在文本框中。

用java写一个Student对象信息，声明StudentJFrame框架类和StudentJPanel对象信息面板，要求①增加查找组合框数据项，提供Person类按省份、城市等多种查找依据提供按姓氏、出生年份等进行模糊查询。② 使用一种日期组件 输入 生日期。③设置省份和城市组合框为可编辑的，将输入的省份和城市字符串添加到各组合框数据项。要求需要用到JTable组件，用java写出

好的，以下是用Java写的一个实现。

首先是Student类，包括姓名、性别、生日、省份、城市等信息：

public class Student {
    private String name;
    private String gender;
    private LocalDate birthday;
    private String province;
    private String city;

    public Student(String name, String gender, LocalDate birthday, String province, String city) {
        this.name = name;
        this.gender = gender;
        this.birthday = birthday;
        this.province = province;
        this.city = city;
    }

    // getter and setter methods
}

然后是StudentJPanel类，包括一个组合框、一个文本框、一个日期组件和两个可编辑的省份和城市组合框：

import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import java.awt.*;
import java.time.LocalDate;
import java.util.ArrayList;
import java.util.List;

public class StudentJPanel extends JPanel {
    private JComboBox<String> searchComboBox;
    private JTextField searchTextField;
    private JTable studentTable;
    private DefaultTableModel tableModel;
    private JTextField nameTextField;
    private JComboBox<String> genderComboBox;
    private JSpinner birthdaySpinner;
    private JComboBox<String> provinceComboBox;
    private JComboBox<String> cityComboBox;

    private List<Student> studentList = new ArrayList<>();

    public StudentJPanel() {
        setLayout(new BorderLayout());

        // search panel
        JPanel searchPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
        searchComboBox = new JComboBox<>(new String[]{"省份", "城市", "姓氏", "出生年份"});
        searchTextField = new JTextField(20);
        JButton searchButton = new JButton("查询");
        searchButton.addActionListener(e -> search());
        searchPanel.add(searchComboBox);
        searchPanel.add(searchTextField);
        searchPanel.add(searchButton);
        add(searchPanel, BorderLayout.NORTH);

        // student table
        tableModel = new DefaultTableModel(new String[]{"姓名", "性别", "生日", "省份", "城市"}, 0);
        studentTable = new JTable(tableModel);
        JScrollPane scrollPane = new JScrollPane(studentTable);
        add(scrollPane, BorderLayout.CENTER);

        // add panel
        JPanel addPanel = new JPanel(new GridLayout(0, 2));
        nameTextField = new JTextField();
        genderComboBox = new JComboBox<>(new String[]{"男", "女"});
        birthdaySpinner = new JSpinner(new SpinnerDateModel());
        JSpinner.DateEditor dateEditor = new JSpinner.DateEditor(birthdaySpinner, "yyyy-MM-dd");
        birthdaySpinner.setEditor(dateEditor);
        provinceComboBox = new JComboBox<>();
        cityComboBox = new JComboBox<>();
        provinceComboBox.setEditable(true);
        cityComboBox.setEditable(true);
        JButton addButton = new JButton("添加");
        addButton.addActionListener(e -> addStudent());
        addPanel.add(new JLabel("姓名"));
        addPanel.add(nameTextField);
        addPanel.add(new JLabel("性别"));
        addPanel.add(genderComboBox);
        addPanel.add(new JLabel("生日"));
        addPanel.add(birthdaySpinner);
        addPanel.add(new JLabel("省份"));
        addPanel.add(provinceComboBox);
        addPanel.add(new JLabel("城市"));
        addPanel.add(cityComboBox);
        addPanel.add(new JLabel());
        addPanel.add(addButton);
        add(addPanel, BorderLayout.SOUTH);
    }

    private void search() {
        String searchBy = (String) searchComboBox.getSelectedItem();
        String keyword = searchTextField.getText().trim();
        tableModel.setRowCount(0);
        for (Student student : studentList) {
            boolean match = false;
            switch (searchBy) {
                case "省份":
                    if (student.getProvince().equals(keyword)) {
                        match = true;
                    }
                    break;
                case "城市":
                    if (student.getCity().equals(keyword)) {
                        match = true;
                    }
                    break;
                case "姓氏":
                    if (student.getName().startsWith(keyword)) {
                        match = true;
                    }
                    break;
                case "出生年份":
                    if (String.valueOf(student.getBirthday().getYear()).startsWith(keyword)) {
                        match = true;
                    }
                    break;
            }
            if (match) {
                tableModel.addRow(new Object[]{student.getName(), student.getGender(), student.getBirthday(),
                        student.getProvince(), student.getCity()});
            }
        }
    }

    private void addStudent() {
        String name = nameTextField.getText().trim();
        String gender = (String) genderComboBox.getSelectedItem();
        LocalDate birthday = ((SpinnerDateModel) birthdaySpinner.getModel()).getDate().toInstant()
                .atZone(java.time.ZoneId.systemDefault()).toLocalDate();
        String province = (String) provinceComboBox.getSelectedItem();
        String city = (String) cityComboBox.getSelectedItem();
        Student student = new Student(name, gender, birthday, province, city);
        studentList.add(student);
        tableModel.addRow(new Object[]{student.getName(), student.getGender(), student.getBirthday(),
                student.getProvince(), student.getCity()});
        provinceComboBox.addItem(province);
        cityComboBox.addItem(city);
    }
}

最后是StudentJFrame类，包括一个StudentJPanel对象信息面板：

import javax.swing.*;

public class StudentJFrame extends JFrame {
    public StudentJFrame() {
        setTitle("学生信息管理系统");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(600, 400);
        setLocationRelativeTo(null);

        StudentJPanel studentJPanel = new StudentJPanel();
        setContentPane(studentJPanel);

        JMenuBar menuBar = new JMenuBar();
        JMenu fileMenu = new JMenu("文件");
        JMenuItem saveMenuItem = new JMenuItem("保存");
        saveMenuItem.addActionListener(e -> save());
        JMenuItem exitMenuItem = new JMenuItem("退出");
        exitMenuItem.addActionListener(e -> System.exit(0));
        fileMenu.add(saveMenuItem);
        fileMenu.add(exitMenuItem);
        menuBar.add(fileMenu);
        setJMenuBar(menuBar);
    }

    private void save() {
        // save student information to file
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new StudentJFrame().setVisible(true));
    }
}

可以看到，实现中使用了JTable组件来展示学生信息，使用了一个组合框和一个文本框来进行查询操作，使用了一个日期组件来输入学生的生日信息，使用了两个可编辑的省份和城市组合框来输入学生的省份和城市信息。同时，添加学生信息的操作也很简单，只需要填写相应的信息即可。

希望这个实现可以对你有所帮助！