救急！怎样用JAVA的GUI（图形用户界面）来设计一个小程序！求程序和详解。

给你找了一个，我试过，可以用
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.*;//GUi之前要吧这两个都引进来
public class Computer extends JFrame implements ActionListener
{
JButton a1,a2,a3,a4,a5,a6,a7,a8,a9,a0;
JButton b1,b2,b3,b4;
JButton c1,c2,c3,c4;
JTextField t1,t2;
JPanel p1,p2;
JLabel bq1,bq2;
String fuhao;
Double count,count2;
boolean chose=false,cliks;

public static void main(String[] args){
Computer l = new Computer();
}
public Computer(){
Font font = new Font("宋体", Font.BOLD, 36);
Font font2 = new Font("宋体", Font.BOLD, 20);

a1 = new JButton("1");
a1.setFont(font);
a1.addActionListener(this);
a2 = new JButton("2");
a2.setFont(font);
a2.addActionListener(this);
a3 = new JButton("3");
a3.setFont(font);
a3.addActionListener(this);
a4 = new JButton("4");
a4.setFont(font);
a4.addActionListener(this);
a5 = new JButton("5");
a5.setFont(font);
a5.addActionListener(this);
a6 = new JButton("6");
a6.setFont(font);
a6.addActionListener(this);
a7 = new JButton("7");
a7.setFont(font);
a7.addActionListener(this);
a8 = new JButton("8");
a8.setFont(font);
a8.addActionListener(this);
a9 = new JButton("9");
a9.setFont(font);
a9.addActionListener(this);
a0 = new JButton("0");
a0.setFont(font);
a0.addActionListener(this);

b1 = new JButton("清空");
b1.addActionListener(this);
b2 = new JButton("返回");
b2.addActionListener(this);
b3 = new JButton(".");
b3.addActionListener(this);

b4 = new JButton("=");
b4.addActionListener(this);

c1 = new JButton("+");
c1.addActionListener(this);

c2 = new JButton("-");
c2.addActionListener(this);
c3 = new JButton("x");
c3.addActionListener(this);
c4 = new JButton("÷");
c4.addActionListener(this);

t1 = new JTextField(25);
t2 = new JTextField(35);
t1.setFont(font2);
t2.setFont(font2);

p1 = new JPanel();
p2 = new JPanel();

bq1 = new JLabel("结");
bq2 = new JLabel("果");

p1.setLayout(new GridLayout(2,3));
p2.setLayout(new GridLayout(4,4));

p1.add(t1);p1.add(b1);p1.add(b2);
p1.add(t2);p1.add(bq1);p1.add(bq2 );

p2.add(a1);p2.add(a2);p2.add(a3);p2.add(c1);
p2.add(a4);p2.add(a5);p2.add(a6);p2.add(c2);
p2.add(a7);p2.add(a8);p2.add(a9);p2.add(c3);
p2.add(b3);p2.add(a0);p2.add(b4);p2.add(c4);

this.add(p1,BorderLayout.NORTH);
this.add(p2,BorderLayout.CENTER);

this.setSize(460,380);
this.setTitle("简易计算器");
this.setLocation(200,200);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
}
public void actionPerformed(ActionEvent e){
Object temp = e.getSource();
if(temp == a1){
if(chose==true){t1.setText("");t2.setText("");}
t1.setText(t1.getText()+""+"1");
chose=false;
}
if(temp == a2){
if(chose==true){t1.setText("");t2.setText("");}
t1.setText(t1.getText()+""+"2");
chose=false;

}
if(temp == a3){
if(chose==true){t1.setText("");t2.setText("");}
t1.setText(t1.getText()+""+"3");
chose=false;

}
if(temp == a4){
if(chose==true){t1.setText("");t2.setText("");}
t1.setText(t1.getText()+""+"4");
chose=false;
}
if(temp == a5){
if(chose==true){t1.setText("");t2.setText("");}
t1.setText(t1.getText()+""+"5");
chose=false;
}
if(temp == a6){
if(chose==true){t1.setText("");t2.setText("");}
t1.setText(t1.getText()+""+"6");
chose=false;
}
if(temp == a7){
if(chose==true){t1.setText("");t2.setText("");}
t1.setText(t1.getText()+""+"7");
chose=false;
}
if(temp == a8){
if(chose==true){t1.setText("");t2.setText("");}
t1.setText(t1.getText()+""+"8");
chose=false;
}
if(temp == a9){
if(chose==true){t1.setText("");t2.setText("");}
t1.setText(t1.getText()+""+"9");
chose=false;
}
if(temp == a0){
if(chose==true){t1.setText("");t2.setText("");}
t1.setText(t1.getText()+""+"0");
chose=false;
}
if(temp==b3){
cliks=true;
for(int i=0;iif('.'==t1.getText().charAt(i)){
cliks=false;
break;
}
if(cliks==true){
t1.setText(t1.getText()+".");
}
}
}

if(temp== c1){
count=Double.parseDouble(t1.getText());
t1.setText("");
fuhao = "+";
}
if(temp== c2){
count=Double.parseDouble(t1.getText());
t1.setText("");
fuhao = "-";
}
if(temp== c3){
count=Double.parseDouble(t1.getText());
t1.setText("");
fuhao = "*";
}

if(temp== c4){
count=Double.parseDouble(t1.getText());
t1.setText("");
fuhao = "÷";
}
if(temp==b1){
t1.setText("");
t2.setText("");
}
if(temp==b2){
String s=t1.getText();
t1.setText("");
for(int i=0;ichar a = s.charAt(i);
t1.setText(t1.getText()+a);
}
}
if(temp== b4){
count2=Double.parseDouble(t1.getText());
t1.setText("");
if(fuhao=="+"){
//int sum=count+count2;
t1.setText(count+""+fuhao+""+count2+""+"=");
t2.setText(count+count2+"");
chose=true;
}
if(fuhao=="-"){
//int sum=count+count2;
t1.setText(count+""+fuhao+""+count2+""+"=");
t2.setText(count-count2+"");
chose=true;
}
if(fuhao=="*"){
//int sum=count+count2;
t1.setText(count+""+fuhao+""+count2+""+"=");
t2.setText(count*count2+"");
chose=true;
}
if(fuhao=="÷"){
//int sum=count+count2;
if(count2==0){
t1.setText(count+""+fuhao+""+count2+"");
t2.setText("除数不能为0");
return;
}
t1.setText(count+""+fuhao+""+count2+""+"=");
t2.setText(count/count2+"");
chose=true;
}

}
}
}