java - 返回填充的 JComboBox 的值并使用该值填充 JTextField

Question

我正在编写一个 JFrame，它通过 JMenubar 打开 JOptionPane。 JOptionPane 确实有一个包含许多不同字符串值的组合框。 JComboBox 之后有一个 JTextfield。

我希望将在 JComboBox 中选择的文本插入到下一个 JTextField 中，并在每次我在 JComboBox 中选择新字符串值时进行更新。

请帮忙!

class DateiAdapter implements ActionListener {

public void actionPerformed(ActionEvent event) {

    JMenuItem change = (JMenuItem) event.getSource();

    JComboBox alleQuest = new JComboBox(ah.getLine(1)); //this ComboBox gets a lot of different values from a different class

    // Actionlistener
    ActionListener cbActionListener = new ActionListener() {

        public void actionPerformed(ActionEvent e) {

            String s = (String) allQuest.getSelectedItem(); //gets the selected string of the JComboBox
            System.out.println("\n" + s); // I want to use String s outside of here, too
            }
        };

        allQuest.addActionListener(cbActionListener);

        JTextField questions = new JTextField(); //THIS is the TextField I want to insert the different values of the ComboBox above
        JTextField a2 = new JTextField();
        JTextField b2 = new JTextField();
        JTextField c2 = new JTextField();
        JTextField answ2 = new JTextField();

        if (change == itemChange) {

            final JComponent[] input = new JComponent[] {
                    new JLabel("You change your question here:"),
                    allQuest,
                    quest2,
                    a2,
                    b2,
                    c2,
                    answ2,  };

            JOptionPane.showMessageDialog(null, input, "Change Question", JOptionPane.PLAIN_MESSAGE);

Answer 1

你可以使用

questions.setText(alleQuest.getSelectedItem().toString());

在 ActionListener 内。但是问题textfileld应该定义在actionPerformed方法之上