calculater.java

利用JAVA实现一个计算器

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

public class Calculater extends JApplet { 
JMenu[] menus = { new JMenu("选项"),new JMenu("关于")}; 
JMenuItem[] items = {new JMenuItem("关于"),new JMenuItem("设置背景色") }; 
JButton b1 = new JButton("运算"); 
JOptionPane b2 = new JOptionPane("运算..."); 
JTextField txt1 = new JTextField("100",10); 
JTextField txt2 = new JTextField("200",10); 
JTextField txt3 = new JTextField(20); 
JLabel[] label = {new JLabel("+"),new JLabel("=")}; 
JColorChooser jcc = new JColorChooser(); 

ActionListener al = new ActionListener() { 
public void actionPerformed(ActionEvent e){ 
//String name = ((JButton)e.getSource()).getText(); 
int m = JOptionPane.showConfirmDialog(null, "继续进行运算吗?", "确定",JOptionPane.YES_NO_OPTION); 
if(m==0){ 
String op1 = txt1.getText(); 
String op2 = txt2.getText(); 
txt3.setText(bussiness(op1,op2)); 
//txt3.setText(m+""); 
} 
} 
}; 
ActionListener al2 = new ActionListener() { 
public void actionPerformed(ActionEvent e){ 
JOptionPane.showMessageDialog(null, "作者：黑雪小组", "关于...",JOptionPane.INFORMATION_MESSAGE); 
} 
}; 
ActionListener al3 = new ActionListener() { 
public void actionPerformed(ActionEvent e){ 

JColorChooser.createDialog(null,"背景色...",true,jcc,al4,null).show(); 
} 
}; 
ActionListener al4 = new ActionListener() { 
public void actionPerformed(ActionEvent e){ 
changeFace(0,jcc.getColor()); 
} 
}; 
public void init() { 
//initialize layout. 
Container cp = getContentPane(); 
cp.setLayout(new FlowLayout()); 
//set menu bar. 
menus[0].add(items[1]); 
items[1].addActionListener(al3); 
menus[1].add(items[0]); 
items[0].addActionListener(al2); 
JMenuBar mb = new JMenuBar(); 
for(int i = 0; i < menus.length; i++) 
mb.add(menus[i]); 
setJMenuBar(mb); 

//add 3 JTextfield. 
cp.add(txt1); 
cp.add(label[0]); 
cp.add(txt2); 
cp.add(label[1]); 
cp.add(txt3); 

//add 1 button with JOptionPane 
cp.add(b1); 
b1.addActionListener(al); 
} 
void changeFace(int i,Object o){ 
if(i==0){ 
//设置背景色 
this.getContentPane().setBackground((Color)o); 
//setBackground((Color)o); 
} 
} 
String bussiness(String op1,String op2){ 
int result=0; 
int op11=0; 
int op21=0; 
try{ 
op11=Integer.parseInt(op1); 
}catch(Exception e1){ 

} 
try{ 
op21=Integer.parseInt(op2); 
}catch(Exception e1){ 

} 
result=op11+op21; 
return ""+result; 
} 
public static void main(String[] args) { 
JApplet applet = new Calculater(); 
JFrame frame = new JFrame("计算器"); 
// To close the application: 
//Console.setupClosing(frame); 
frame.getContentPane().add(applet); 
frame.setSize(260,140); 
applet.init(); 
applet.start(); 
frame.setVisible(true); 
} 
} ///:~