这个更换布局center pannel怎么个写法?

Question

package test;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;import javax.swing.*;
public class Fram {
public static void main(String[] args) {
        JFrame jf = new JFrame();
      // jf.setDefaultCloseOperation(operation)
        final Container conPan = jf.getContentPane();       
       JPanel jp1 = new JPanel();
       jp1.setBackground( Color.black);
       jp1.setLayout(new FlowLayout());
       JButton jb1 = new JButton("铵钮1");
       JButton jb2 = new JButton("铵钮1");
       JButton jb3 = new JButton("铵钮1");    
       jb3.setPreferredSize(new Dimension(20,19));
      // jb3.setSize(100, 150);
       //jp1.setSize(200, 300);
       jp1.setPreferredSize(new Dimension(200,189));
       jp1.add(jb1);
       jp1.add(jb2);
       jp1.add(jb3);       
       final JPanel jp2 = new JPanel();
       jp2.setBackground(Color.blue);
       final JPanel jp3 = new JPanel();
       jp3.setBackground(Color.gray);       
       conPan.setLayout(new BorderLayout());
       conPan.add(jp1,"North");
       //conPan.add(jp2,"West");
      // conPan.add(jp3,"Center");      
       conPan.add(jp3,"Center");    
       conPan.add(jp2,"Center");
       conPan.add(jp2,"Center");// 这里是可以的.     
       
     //  final JPanel jp4 = new JPanel();
     //  jp4.setBackground(Color.green);
     //  JPanel jp5 = new JPanel();
     //  jp5.setBackground(Color.orange);
    //   jp2.setLayout(new BorderLayout());
      // jp2.add(jp4,"North");
      // jp2.add(jp5,"Center");
       
       jb1.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent Event){
        System.out.println('a');
        conPan.add(jp3,"Center");//~~~~疑问就在这里,怎么这句不起作用呢? 要怎么写呢?
        //conPan.repaint();
      // jf.repaint();
       // jp2.setVisible(true);
       // conPan.repaint();
        //conPan.setVisible(true);
        
        //jp2.add(jp4,"Center");
       // jp2.setVisible(true);
        //jp4.setVisible(true);
       // jp2.repaint();
        
        }
       });
       jf.setSize(600, 500);
       jf.setVisible(true);
}}

Answer 1

       jb1.addActionListener(new ActionListener(){
           public void actionPerformed(ActionEvent Event){
               System.out.println('a');
               conPan.add(jp3,"Center");//~~~~疑问就在这里,怎么这句不起作用呢? 要怎么写呢?
               conPan.validate(); // 加这一句使用布局生效
               //conPan.repaint();
             // jf.repaint();
              // jp2.setVisible(true);
              // conPan.repaint();
               //conPan.setVisible(true);
               
               //jp2.add(jp4,"Center");
              // jp2.setVisible(true);
               //jp4.setVisible(true);
              // jp2.repaint();
               
           }
       });

Answer 2

你的代码太乱。具体实现思路可以参考。import java.awt.FlowLayout;import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.border.TitledBorder;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;import javax.swing.*;
public class Test {
 JFrame jf = new JFrame();
 JPanel jp3 = new JPanel();

    public static void main(String[] args) {
     Test t=new Test();
     JFrame jf=t.jf;
      // jf.setDefaultCloseOperation(operation)
        Container conPan = jf.getContentPane();       
       JPanel jp1 = new JPanel();
       jp1.setBackground( Color.black);
       jp1.setLayout(new FlowLayout());
       JButton jb1 = new JButton("铵钮1");
       JButton jb2 = new JButton("铵钮1");
       JButton jb3 = new JButton("铵钮1");    
       jb3.setPreferredSize(new Dimension(20,19));
      // jb3.setSize(100, 150);
       //jp1.setSize(200, 300);
       jp1.setPreferredSize(new Dimension(200,189));
       jp1.add(jb1);
       jp1.add(jb2);
       jp1.add(jb3);       
       final JPanel jp2 = new JPanel();
       jp2.setBackground(Color.blue);
       
       t.jp3.setBackground(Color.gray);       
       conPan.setLayout(new BorderLayout());
       conPan.add(jp1,"North");
       //conPan.add(jp2,"West");
      // conPan.add(jp3,"Center");      
       conPan.add(t.jp3,"Center");    
       conPan.add(jp2,"Center");
       conPan.add(jp2,"Center");// 这里是可以的.     
       
     //  final JPanel jp4 = new JPanel();
     //  jp4.setBackground(Color.green);
     //  JPanel jp5 = new JPanel();
     //  jp5.setBackground(Color.orange);
    //   jp2.setLayout(new BorderLayout());
      // jp2.add(jp4,"North");
      // jp2.add(jp5,"Center");
       jb1.addActionListener(new ActionListerSimple());
       
//           public void actionPerformed(ActionEvent Event){
//               System.out.println('a');
//
//               conPan.add(jp3,"Center");//~~~~疑问就在这里,怎么这句不起作用呢? 要怎么写呢?
//               //conPan.repaint();
//             // jf.repaint();
//              // jp2.setVisible(true);
//              // conPan.repaint();
//               //conPan.setVisible(true);
//               
//               //jp2.add(jp4,"Center");
//              // jp2.setVisible(true);
//               //jp4.setVisible(true);
//              // jp2.repaint();
//               
//           }
       
       jf.setSize(600, 500);
       jf.setVisible(true);
    }
}
class ActionListerSimple implements ActionListener{
private JFrame jf =this.jf;
private JPanel jp3=this.jp3;
public void actionPerformed(ActionEvent e) {
  System.out.println('a');
          jf.add(jp3,"Center");
}

}

Answer 3

多谢两位... 这个good.. 就是要这种效果.