java如何从匿名ActionListener访问JFrame，以便在框架中添加面板？

Question

如果点击某个按钮，我想在一个框架中添加一个JPanel，但我不知道如何从匿名ActionListener管理它。以下是代码：

public class MyFrame extends JFrame {
   JPanel panel;
   JButton button;
   public MyFrame() {
      button = new JButton("Add panel");
      button.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent event) {
            panel = new JPanel();
            //here I want to add the panel to frame: this.add(panel), but I don't know
            //how to write that. In these case "this" refers to ActionListener, not to
            //frame, so I want to know what to write instead of "this" in order to
            //refer to the frame
         }
      }
      this.add(button);
  }

提前谢谢

Answer 1

here I want to add the panel to frame: this.add(panel), but I don't know how to write that. In these case "this" refers to ActionListener, not to frame, so I want to know what to write instead of "this" in order to refer to the frame

在匿名类中使用this意味着你指的是ActionListener实例，而不是this.add(...)只需使用add(..)或者你可以使用MyFrame.this.add(..)

实际上，在添加组件后，您可能还需要调用revalidate()和repaint()

Answer 2

在ActionListener中使用通用代码，这样就不需要硬编码正在使用的类

比如：

JButton button = (JButton)event.getSource();
Window window = SwingUtilities.windowForCompnent( button );
window.add(...);

Answer 3

public class MyFrame extends JFrame {
   JPanel panel;
   JButton button;
   public MyFrame() {
      button = new JButton("Add panel");
      button.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent event) {
            panel = new JPanel();
            //here I want to add the panel to frame: this.add(panel), but I don't know
            //how to write that. In these case "this" refers to ActionListener, not to
            //frame, so I want to know what to write instead of "this" in order to
            //refer to the frame
            MyFrame.this.add(panel);
         }
      }
      this.add(button);
  }