请各个多多指点

Question

package design;
import java.awt.*;import javax.swing.*;
public class ControlPanel extends JFrame  {
public JButton moveleft;
 public JButton moveright;
 public JButton moveup;
 public JButton movedown;
 public JButton focus;
 public JButton connection;
 public ControlPanel(int a){
         setLayout(new BorderLayout());
         JPanel jpanel = new JPanel();
                moveleft = new JButton("向左移动");
         moveright = new JButton("向右移动");
         moveup    = new JButton("向上移动");
         movedown =  new JButton("向下移动");
         focus    =  new JButton("聚焦");
         connection = new JButton("连接");
            jpanel.add(moveleft,BorderLayout.EAST);  
            jpanel.add(moveright,BorderLayout.WEST);
            jpanel.add(moveup,BorderLayout.NORTH);
            jpanel.add(movedown,BorderLayout.SOUTH);
            jpanel.add(focus,BorderLayout.CENTER);
            jpanel.add(connection,BorderLayout.NORTH);
                     add(jpanel,BorderLayout.CENTER);
         }
         public static void main (String[] args){
          JFrame frame = new JFrame("控制台");
          frame.getContentPane();
          frame.setSize(400,300);
          frame.setVisible(true);
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         }
}
问题是所声明控键没有添加到面板里面去。

Answer 1

public ControlPanel(int a){ 
        setLayout(new BorderLayout()); 
        JPanel jpanel = new JPanel(); 
                moveleft = new JButton("向左移动"); 
        moveright = new JButton("向右移动"); 
        moveup    = new JButton("向上移动"); 
        movedown =  new JButton("向下移动"); 
        focus    =  new JButton("聚焦"); 
        connection = new JButton("连接"); 
            jpanel.add(moveleft,BorderLayout.EAST); 
            jpanel.add(moveright,BorderLayout.WEST); 
            jpanel.add(moveup,BorderLayout.NORTH); 
            jpanel.add(movedown,BorderLayout.SOUTH); 
            jpanel.add(focus,BorderLayout.CENTER); 
            jpanel.add(connection,BorderLayout.NORTH); 
                    add(jpanel,BorderLayout.CENTER); 
            setSize(800, 600);
            setVisible(true);
        } 

Answer 2

public ControlPanel(int a){ 
        setLayout(new BorderLayout()); 
        JPanel jpanel = new JPanel(); 
                moveleft = new JButton("向左移动"); 
        moveright = new JButton("向右移动"); 
        moveup    = new JButton("向上移动"); 
        movedown =  new JButton("向下移动"); 
        focus    =  new JButton("聚焦"); 
        connection = new JButton("连接"); 
            jpanel.add(moveleft,BorderLayout.EAST); 
            jpanel.add(moveright,BorderLayout.WEST); 
            jpanel.add(moveup,BorderLayout.NORTH); 
            jpanel.add(movedown,BorderLayout.SOUTH); 
            jpanel.add(focus,BorderLayout.CENTER); 
            jpanel.add(connection,BorderLayout.NORTH); 
                    add(jpanel,BorderLayout.CENTER); 
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.getContentPane(); 
            setSize(400,300);
        } 
public static void main(String[] args)
{
        JFrame frame = new JFrame("控制台"); 
        frame.setVisible(true); 
} 

Answer 3

public ControlPanel(int a){ 
        Container c=getContentPane();
        c.setLayout(new BorderLayout()); 
        JPanel jpanel = new JPanel(); 
                moveleft = new JButton("向左移动"); 
        moveright = new JButton("向右移动"); 
        moveup    = new JButton("向上移动"); 
        movedown =  new JButton("向下移动"); 
        focus    =  new JButton("聚焦"); 
        connection = new JButton("连接"); 
            jpanel.add(moveleft,BorderLayout.EAST); 
            jpanel.add(moveright,BorderLayout.WEST); 
            jpanel.add(moveup,BorderLayout.NORTH); 
            jpanel.add(movedown,BorderLayout.SOUTH); 
            jpanel.add(focus,BorderLayout.CENTER); 
            jpanel.add(connection,BorderLayout.NORTH); 
            
            //将面板jpanel添加到容器c中，面板必须依靠容器才能在框架中显示出来
            c.add(jpanel,BorderLayout.CENTER); 
           
            setSize(800, 600); 
            setVisible(true); 
        } 

Answer 4

细节自己去调整吧   给分吧  哇哈哈import java.awt.*; 
import javax.swing.*; public class ControlPane extends JFrame  { 
public JButton moveleft; 
public JButton moveright; 
public JButton moveup; 
public JButton movedown; 
public JButton focus; 
public JButton connection; 

public ControlPane(int a){ 
super("控制台");

Container container = getContentPane();

        this.setLayout(new BorderLayout()); 
        JPanel jpanel = new JPanel(); 
        moveleft = new JButton("向左移动"); 
        moveright = new JButton("向右移动"); 
        moveup    = new JButton("向上移动"); 
        movedown =  new JButton("向下移动"); 
        focus    =  new JButton("聚焦"); 
        connection = new JButton("连接"); 
        container.add(moveleft,BorderLayout.EAST); 
        container.add(moveright,BorderLayout.WEST); 
        container.add(moveup,BorderLayout.NORTH); 
        container.add(movedown,BorderLayout.SOUTH); 
        container.add(focus,BorderLayout.CENTER); 
        container.add(connection,BorderLayout.NORTH); 
        container.add(jpanel,BorderLayout.CENTER); 
                    
        setSize(400,300);
        setVisible(true);
    } 
        
public static void main (String[] args){ 
        ControlPane cp = new ControlPane(0);        cp.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    } 
} 

Answer 5

创建这个类的对象，并且构造器中参数int a 没用，我给去掉了。
ControlPanel frame = new ControlPanel();而不是创建JFrame frame = new JFrame("控制台"); 的对象。

Answer 6

JPanel的默认布局不是BorderLayout，所以需要设置jpanel的布局。
jpanel.setLayout(new BorderLayout());