停止JOptionPane.showConfirmDialog显示2次？

Question

请阅读到最后，我有3个问题。这是我的代码：

public class oncancel implements ActionListener {

  public void actionPerformed(ActionEvent event) {

    int confirm=JOptionPane.showConfirmDialog(null, "exit window ?",
      "msgbox",JOptionPane.YES_NO_OPTION);

     if(confirm==JOptionPane.YES_OPTION){ 
        new graphic();
     }     //returns to the main frame

  }
}

1）此代码出现2次但是它应该只出现一次??

2）当我选择是时，此代码会打开一个新窗口但是如果我想要保持在同一个窗口中，例如＆＃34;返回到主页面＆＃34; ??

3）此代码位于＆＃34; x1＆＃34;上课＆＃34;取消＆＃34;按钮。如果单击是，则应返回＆＃34; x＆＃34;类

有类似

的东西

{
  new graphic().x();
} ??

感谢您的时间：））

public class graphic { 
...
xbutton.addActionListener(new x()); -->this one's in graphic
...
}

private class x implements ActionListener {
    public void actionPerformed(ActionEvent event) {
       ...
       x1button.addActionListener(new x1());
       ....
}}

public class x1 implements ActionListener {
    public void actionPerformed(ActionEvent event) {
     ...
     cancel.addActionListener(new oncancel());
     ...
}}

public class oncancel implements ActionListener {
    public void actionPerformed(ActionEvent event) {
        int confirm=JOptionPane.showConfirmDialog(null, "exit window?", "msg box", JOptionPane.YES_NO_OPTION);
        if(confirm==JOptionPane.YES_OPTION) { 
            new graphic();
        }
    }
}