Question

我试图在点击Jbutton jbtcredits后从父类中的JPanel更改为子类中的JPanel。我尝试在子类中实现cardlayout但是，JFrame没有更新，旧的JPanel是当我想从子类中显示我的新JPanel时仍然存在。我还按照某人的建议添加了invalidate（）和repaint（），但它仍然不起作用。只有JFrame标题发生变化。

我的父类代码如下：

private JButton jbtstart= new JButton("Start Cooking!");
private JButton jbtabout = new JButton("About");
 JButton jbtcredits = new JButton("Credits");
private JButton jbtexit = new JButton("Exit");
private JLabel Screen;
static JFrame frame = new JFrame("f");
JPanel p1 = new JPanel();
JPanel p = new JPanel();
 JLabel back=new JLabel(new ImageIcon("C:\\Users\\Desktop\\background.png"));

//private static int gridSize = 2;

public GUI_interface()
{
    super("GUIinterface");
}



public void createAndDisplayGUI()
{   
    Screen=new JLabel(new ImageIcon("C:\\Users\\Desktop\\Title.png"));


    jbtstart.setLayout(new BorderLayout());




    //JPanel p = new JPanel();

    //p.setLayout(null);



    p1.setLayout(new GridLayout(1,1));

    p.setLayout(new BorderLayout());

    back.setLayout(new FlowLayout());

    jbtstart.setPreferredSize(new Dimension(40, 40));


    p.add(Screen,BorderLayout.NORTH);
    p.add(jbtstart);
    p1.add(jbtabout);
    p1.add(jbtcredits);
    p1.add(jbtexit);

    back.add(p);
    back.add(p1);

    jbtstart.addActionListener(this);
    jbtabout.addActionListener(this);
    jbtcredits.addActionListener(this);
    jbtexit.addActionListener(this);



    setContentPane(back);




   frame.setTitle("Cooking App");

   frame.setLocation(300,250);
   frame.setResizable(false);
   frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   frame.add(back);
   frame.pack();
   frame.setLocationByPlatform(true);
   frame.setVisible(true);
}

public void actionPerformed(ActionEvent e)
{
// find out which button was pressed

 if (e.getSource()==jbtstart)
  {
     JOptionPane.showMessageDialog(null,"to be added");
  }
  else if (e.getSource() == jbtabout)
  {
      About files=new About();
      //files.setSize(20, 30);
      files.createAndDisplayGUI();
  }
  else if (e.getSource() == jbtcredits)
  {

     Credits filess=new Credits();
     filess.createAndDisplayGUI();

 }
  else
  {

      { Object[] options = {"Yes","No"};
        int n = JOptionPane.showOptionDialog(null,
                       "Are you sure you would like to quit? ","Cooking App",
                       JOptionPane.PLAIN_MESSAGE,
                       JOptionPane.QUESTION_MESSAGE,
                       null,
                       options,
                       options[1]);
        if (n==0)
        {
            System.exit(0);
        }
      }
  }
      // end the program





public static void main(String[] args)
{

    SwingUtilities.invokeLater(new Runnable()
    {
        public void run()
        {
            new GUI_interface().createAndDisplayGUI();
        }
    });
}

这是我的子课程，我正在实施CardLayout：

private JButton jbtback = new JButton("back");
JPanel a =new JPanel();
JPanel b=new JPanel();
JPanel c=new JPanel();
String text="Victory is a term, originally applied"
        + " to warfare, given to success achieved in personal combat, "
        + "after military operations in general or, by extension, in any"
        + " competition.";

CardLayout c1= new CardLayout();
public void createAndDisplayGUI(){



a.setLayout(c1);
JLabel back1=new JLabel(new ImageIcon("C:\\Users\\Desktop\\background.png"));
JLabel info=new JLabel("<html>"+text+"</html>");;

jbtback.setLayout(new BorderLayout());

//
p1.setLayout(new GridLayout(1,1));

c.add(info,BorderLayout.NORTH);
c.add(jbtback);


back1.add(c);


//

b.add(back1);

a.add(back,"1");
a.add(b,"2");
c1.show(a,"1");

setContentPane(a);

//a.add(back,"1");
//a.add(jbtback,"2");

jbtcredits.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent e)
{
// find out which button was pressed

    c1.show(a,"2");
    frame.invalidate();
    frame.repaint();
  }
});


jbtback.addActionListener(new ActionListener(){
    @Override
    public void actionPerformed(ActionEvent e)
    {
    // find out which button was pressed

        c1.show(a,"1");
        frame.invalidate();
        frame.repaint();
      }
    });

frame.add(a);
frame.setTitle("About us");
frame.setSize(300,250);
frame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
frame.pack();
//frame.setLocationByPlatform(true);
frame.setVisible(true);



}

Cardlayout不在程序中工作

0 个答案: