java嵌套在彼此之上的面板打印

Question

import java.awt.*;
import javax.swing.*;

public class Panels extends JApplet
{
  private Container c = getContentPane();

  public void init()
  {
    BorderLayout bl = new BorderLayout();   
    setLayout(bl);

    add(new JButton("East "),   BorderLayout.EAST);  
    add(new JButton("West "),   BorderLayout.WEST);  
    add(new JButton("North "),  BorderLayout.NORTH); 
    add(new JButton("South "),  BorderLayout.SOUTH);

    addCenterPanel();
  }

  void addCenterPanel()
  {
    JPanel p = new JPanel();
    setLayout(new BorderLayout());

    add(new JButton("Right "),  BorderLayout.EAST);  
    add(new JButton("Left "),   BorderLayout.WEST);  
    add(new JButton("Up "),     BorderLayout.NORTH); 
    add(new JButton("Down "),   BorderLayout.SOUTH);

    addInnermostPanel();
  }

  void addInnermostPanel()
  {
    JPanel center = new JPanel();

    center.setLayout(new BorderLayout());

    add(new JButton("> "),  BorderLayout.EAST);  
    add(new JButton("< "),  BorderLayout.WEST);  
    add(new JButton("^ "),  BorderLayout.NORTH); 
    add(new JButton("v "),  BorderLayout.SOUTH);
    add(new JButton("O"),   BorderLayout.CENTER);  
  }
}

我希望这些面板在彼此之间显示（在CENTER区域中），但是它们却在彼此之间打印，并且出于任何原因，我都无法弄清楚Im缺少了什么。 在此先感谢您的帮助

Answer 1

这是您的代码，应该像这样；

import java.awt.*;
import javax.swing.*;

public class Panels extends JFrame
{
  private Container c = getContentPane();

  public void init()
  {
    BorderLayout bl = new BorderLayout();
    setLayout(bl);
    setDefaultCloseOperation(3);
    setLocationRelativeTo(null);

    add(new JButton("East "),   BorderLayout.EAST);
    add(new JButton("West "),   BorderLayout.WEST);
    add(new JButton("North "),  BorderLayout.NORTH);
    add(new JButton("South "),  BorderLayout.SOUTH);

    add(addCenterPanel(),"Center");
  }

  JPanel addCenterPanel()
  {
    JPanel p = new JPanel();
    p.setLayout(new BorderLayout());

    p.add(new JButton("Right "),  BorderLayout.EAST);
    p.add(new JButton("Left "),   BorderLayout.WEST);
    p.add(new JButton("Up "),     BorderLayout.NORTH);
    p.add(new JButton("Down "),   BorderLayout.SOUTH);

    p.add(addInnermostPanel(),"Center");
    return p;
  }

  JPanel addInnermostPanel()
  {
    JPanel center = new JPanel();

    center.setLayout(new BorderLayout());

    center.add(new JButton("> "),  BorderLayout.EAST);
    center.add(new JButton("< "),  BorderLayout.WEST);
    center.add(new JButton("^ "),  BorderLayout.NORTH);
    center.add(new JButton("v "),  BorderLayout.SOUTH);
    center.add(new JButton("O"),   BorderLayout.CENTER);
    return center;
  }

  public static void main(String ...args){
       new Panels().setVisible(true);
  }
  public Panels(){
      init();
      pack();

  }
}

注意 ：我使用JFrame代替applet。 我也刚刚发布了代码，因为描述整个程序需要花费很多时间，我认为仅代码就足够了。

如果有问题，请在评论中写下。

Answer 2

在addCenterPanel您可以将所有组件直接添加到applet本身，而不是添加到JPanel p 。 该面板未添加到小程序本身。 在addInnermostPanel ，组件再次添加到applet中，而center JPanel从不添加到容器中