java - 按下按钮后在另一个面板内打开另一个面板

Question

我一直收到一条错误消息，说我没有添加一些方法(执行的操作)，但我已经添加了。我在打开面板 2 时遇到问题。

public class panel1 extends JPanel implements ActionListener(){
    private panel2 p2=new panel2();
    private JButton button;

    public panel1(){
    button=new JButton("open panel2");
    add(button,BorderLayout.BEFORE_FIRST_LINE);
    button.addActionListener(new ActionListener(){
        @Override
        public void actionPerformed(ActionEvent ae) {

            add(p2);

        }

    });

  }

Answer 1

考虑这些变化:

public class panel1 extends JPanel implements ActionListener(){
    private panel2 p2=new panel2();
    private JButton button;

    public panel1(){
    button=new JButton("open panel2");
    add(button,BorderLayout.BEFORE_FIRST_LINE);
    button.addActionListener(new ActionListener(){
        @Override
        public void actionPerformed(ActionEvent ae) {
            //Add readability: Where to add?
            panel1.this.add(p2);
        }

    });

  }

  //THIS HERE makes your panel1 implment ActionListener
  @Override
  public void actionPerformed(ActionEvent ae) {

  }
}

另请注意常见的 Java 命名约定 - 类名应以大写字母开头(Panel1 extends JPanel)