如何将输入文本屏幕上的摆动键盘设置为系统插入符号？

Question

我想将任何文本或键从摆动屏幕键盘写到任何插入符号位置，例如浏览器记事本办公室字词。我得到一些示例布局，但不知道如何使用系统插入符号。请教我它的工作原理。

此示例代码

public class keyboard extends JFrame {

    private JPanel contentPane;
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    keyboard frame = new keyboard();
                    frame.setVisible(true);
                    frame.setAlwaysOnTop(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
    public keyboard() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        contentPane.setLayout(new BorderLayout(0, 0));
        setContentPane(contentPane);
        contentPane.setLayout(new GridLayout(3, 3));
        for(int i = 1; i <= 9; i++) { 
            createButton(Integer.toString(i));
            }
        pack();

    }
    private void createButton(String label)
    {
        JButton btn = new JButton(label);
        btn.setFocusPainted(false);
        btn.setPreferredSize(new Dimension(100, 100));
        contentPane.add(btn);
    }

    public void actionPerformed(ActionEvent e)
    {
        addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {

            }
    });


}
}