java se，求教解决思路

package com.yhy.test;import java.awt.GridLayout;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JTextField;public class mult{    public static void main(String[] args) {        ShowGridLayout frame = new ShowGridLayout();        frame.setTitle("GirdLayout");        frame.setLocationRelativeTo(null);        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        frame.setVisible(true);        frame.setSize(200, 200);    }}class ShowGridLayout extends JFrame {    public ShowGridLayout() {        setLayout(new GridLayout(2, 2, 5, 5));        add(new JTextField(5));        add(new JTextField(5));        add(new JButton("*"));        add(new JButton("="));    }}
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Java code
package com.yhy.test;import java.awt.GridLayout;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JTextField;public class mult {    public static void main(String[] args) {        mult m = new mult();        ShowGridLayout frame = m.new ShowGridLayout();//实例化一个嵌套类的方法        frame.setTitle("GirdLayout");        frame.setLocationRelativeTo(null);        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        frame.setVisible(true);        frame.setSize(200, 200);    } public    class ShowGridLayout extends JFrame {        public ShowGridLayout() {            setLayout(new GridLayout(2, 2, 5, 5));                add(new JTextField(5));            add(new JTextField(5));            add(new JButton("*"));            add(new JButton("="));            }    }}
------解决方案--------------------
说下LZ的代码，有点受力不讨好。在Mult类内定义内部类 ShowGridLayout 。但还是按照LZ的代码改成可运行的。

import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;


public class Mult {

static public class ShowGridLayout extends JFrame
{
public ShowGridLayout()
{
setLayout(new GridLayout(2,2,5,5));

add(new JTextField(5));
add(new JTextField(5));
add(new JButton("*"));
add(new JButton("="));

}
}  


public static void main(String[]args)
{
ShowGridLayout frame = new ShowGridLayout();

frame.setTitle("GirdLayout");
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.setSize(200,200);

}

}

我觉得LZ的代码最好是改成下面这种形式：代码如下：


import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;