用java实现一个简单的计算器。
import java.awt.*;
import java.awt.event.*;
public class CalcAppDemo extends Frame{
private TextField t_result;
private Panel p_main; //主面板
private Panel p_num; //数字面板
private Panel p_oper; //操作符面板
private Panel p_show; //显示面板
private Button b_num[]; //数字按钮
private Button b_oper[]; //操作符面板
public CalcAppDemo(String title){
setTitle(title);
t_result = new TextField("0.0", 21);
p_main = new Panel();
p_num = new Panel();
p_oper = new Panel();
p_show = new Panel();
p_main.setLayout(new BorderLayout());
p_num.setLayout(new GridLayout(4, 3, 1, 1));
p_oper.setLayout(new GridLayout(4, 2, 1, 1));
b_num = new Button[12];
for(int i=0; i<9; i++)
{
b_num[i] = new Button(new Integer(i+1).toString());
}
b_num[9] = new Button("0");
b_num[10] = new Button("cls");
b_num[11] = new Button(".");
for(int i=0; i<12; i++)
{
p_num.add(b_num[i]);
}
b_oper = new Button[8];
b_oper[0] = new Button("+");
b_oper[1] = new Button("-");
b_oper[2] = new Button("*");
b_oper[3] = new Button("/");
b_oper[4] = new Button("pow");
b_oper[5] = new Button("sqrt");
b_oper[6] = new Button("+/-");
b_oper[7] = new Button("=");
for(int i=0; i<8; i++) //
{
p_oper.add(b_oper[i]);
}
t_result.setEditable(false);
p_show.add(t_result, BorderLayout.NORTH);
p_main.add(p_show, BorderLayout.NORTH);
p_main.add(p_num, BorderLayout.WEST);
p_main.add(p_oper, BorderLayout.EAST);
this.add(p_main, BorderLayout.CENTER);
setSize(400, 400);
setResizable(false);
pack();
this.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
ButtonListener b1 = new ButtonListener();
for(int i=0; i<12; i++)
{
b_num[i].addActionListener(b1);
}
for(int i=0; i<8; i++)
{
b_oper[i].addActionListener(b1);
}
}
class ButtonListener implements ActionListener
{
private String lastOp; //存储上一此操作符
private String strVal; //存储数字对应的字符串
private double total; //总数
private double number; //存储新输入的数
private boolean firsttime; //判断是否第一次按下的是操作符按钮
private boolean operatorPressed;//判断是否已经按过操作符按钮
ButtonListener()
{
firsttime = true;
strVal = "";
}
//事件处理器
public void actionPerformed(ActionEvent e)
{
String s = ((Button)e.getSource()).getLabel().trim();
if(Character.isDigit(s.charAt(0)))
{//判断是操作数还是操作符
handleNumber(s);
}
else
{
calculate(s);
}
}
//判断是一元操作符还是二元操作符，并根据操作符类型做计算
void calculate(String op)
{
operatorPressed = true;
if(firsttime&&! isUnary(op))
{
total = getNumberOnDisplay();
firsttime = false;
}
if(isUnary(op))
{
handleUnaryOp(op);
}
else if(lastOp != null)
{
handleBinaryOp(lastOp);
}
if(! isUnary(op))
{
lastOp = op;
}
}
//判断是否一元操作符
boolean isUnary(String s)
{
return s.equals("=")
||s.equals("cls")||s.equals("sqrt")
||s.equals("+/-")||s.equals(".");
}
//处理一元操作符
void handleUnaryOp(String op)
{
if(op.equals("+/-"))
{//
number = negate(getNumberOnDisplay() + "");
t_result.setText("");
t_result.setText(number + "");
return;
}else if(op.equals("."))
{
handleDecPoint();
return;
}else if(op.equals("sqrt"))
{
number = Math.sqrt(getNumberOnDisplay());
t_result.setText("");
t_result.setText(number + "");
return;
}else if(op.equals("="))
{//
if(lastOp!= null && !isUnary(lastOp))
{
handleBinaryOp(lastOp);
}
lastOp = null;
firsttime = true;
return;
}else
{
clear();
}
}
//处理二元运算符
void handleBinaryOp(String op)
{
if(op.equals("+"))
{
total +=number;
}else if(op.equals("-"))
{
total -=number;
}else if(op.equals("*"))
{
total *=number;
}else if(op.equals("/"))
{
try
{
total /=number;
}catch(ArithmeticException ae){}
}else if(op.equals("pow"))
total = Math.pow(total, number);
//t_result.setText("");
lastOp = null;
// strVal = "";
number = 0;
t_result.setText(total + "");
}
//该方法用于处理数字按钮
void handleNumber(String s)
{
if(!operatorPressed)
{
strVal += s;
}else
{
operatorPressed = false;
strVal = s;
}
//
number = new Double(strVal).doubleValue();
t_result.setText("");
t_result.setText(strVal);
}
//该方法用于按下"."按钮
void handleDecPoint()
{
operatorPressed = false;
//
if(strVal.indexOf(".")<0)
{
strVal += ".";
}
t_result.setText("");
t_result.setText(strVal);
}
//该方法用于将一个数求反
double negate(String s)
{
operatorPressed = false;
//如果是一个整数，去掉小数点后面的0
if(number == (int)number)
{
s = s.substring(0,s.indexOf("."));
}
//如果无"-"增加在该数的前面
if(s.indexOf("-")<0)
{
strVal = "-" + s;
}
else
{
strVal = s.substring(1);
}
return new Double(strVal).doubleValue();
}
//将显示框中的值转换成Double
double getNumberOnDisplay()
{
return new Double(t_result.getText()).doubleValue();
}
//清除屏幕并设置所有的标识
void clear()
{
firsttime = true;
lastOp = null;
strVal = "";
total = 0;
number = 0;
t_result.setText("0");
}
}
public static void main(String[] args) {
CalcAppDemo c = new CalcAppDemo("简单的计算器程序");
c.setVisible(true);
}
}
1.窗体
package Calc;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
*
* 计算器程序
*
*/
public class CalcFrame extends JFrame {
JButton[] buttons = new JButton[16];// 16个按钮
StringBuffer sb = null;//
JTextField text1 = null;// 计算器结果显示框
String no1 = null;
String sign = null;// 表示+-*/符号
String[] s = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "+", "-",
"*", "/", "=", "C" };// 面板上的字符
public CalcFrame() {
setTitle("计算器");
setResizable(false);
setBounds(200, 200, 300, 350);
setLayout(null);
sb = new StringBuffer();
text1 = new JTextField();
text1.setBounds(10, 10, 250, 30);// 设置位置
text1.setFont(new Font("Arial", Font.PLAIN, 20));// 设置字体
text1.setForeground(Color.RED);// 设置颜色
add(text1);
for (int i = 0; i < s.length; i++) {
buttons[i] = new JButton(s[i]);
buttons[i].setFont(new Font("Serif", Font.BOLD, 18));
add(buttons[i]);
}// 生成面板上的按钮.
buttons[0].setBounds(10, 50, 50, 40);
buttons[0].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.append(0);
text1.setText(sb.toString());
}
});
buttons[1].setBounds(70, 50, 50, 40);
buttons[1].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.append(1);
text1.setText(sb.toString());
}
});
buttons[2].setBounds(130, 50, 50, 40);
buttons[2].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.append(2);
text1.setText(sb.toString());
}
});
buttons[3].setBounds(190, 50, 50, 40);
buttons[3].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.append(3);
text1.setText(sb.toString());
}
});
buttons[4].setBounds(10, 100, 50, 40);
buttons[4].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.append(4);
text1.setText(sb.toString());
}
});
buttons[5].setBounds(70, 100, 50, 40);
buttons[5].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.append(5);
text1.setText(sb.toString());
}
});
buttons[6].setBounds(130, 100, 50, 40);
buttons[6].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.append(6);
text1.setText(sb.toString());
}
});
buttons[7].setBounds(190, 100, 50, 40);
buttons[7].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.append(7);
text1.setText(sb.toString());
}
});
buttons[8].setBounds(10, 150, 50, 40);
buttons[8].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.append(8);
text1.setText(sb.toString());
}
});
buttons[9].setBounds(70, 150, 50, 40);
buttons[9].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.append(9);
text1.setText(sb.toString());
}
});
buttons[10].setBounds(130, 150, 50, 40);
buttons[10].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sign = "+";
no1 = text1.getText();
sb.delete(0, sb.capacity());
}
});
buttons[11].setBounds(190, 150, 50, 40);
buttons[11].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sign = "-";
no1 = text1.getText();
sb.delete(0, sb.capacity());
}
});
buttons[12].setBounds(10, 200, 50, 40);
buttons[12].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sign = "*";
no1 = text1.getText();
sb.delete(0, sb.capacity());
}
});
buttons[13].setBounds(70, 200, 50, 40);
buttons[13].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sign = "/";
no1 = text1.getText();
sb.delete(0, sb.capacity());
}
});
buttons[14].setForeground(Color.RED);
buttons[14].setBounds(130, 200, 50, 40);
buttons[14].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
int sum = 0;//最终结果
if (sign.equals("+")) {
int no2 = Integer.parseInt(no1);//取得前一个数
int no3 = Integer.parseInt(text1.getText());//取得现在的数
sum = no2 + no3;//累加
text1.setText(String.valueOf(sum));
}
if (sign.equals("-")) {
int no2 = Integer.parseInt(no1);
int no3 = Integer.parseInt(text1.getText());
sum = no2 - no3;
text1.setText(String.valueOf(sum));
}
if (sign.equals("*")) {
int no2 = Integer.parseInt(no1);
int no3 = Integer.parseInt(text1.getText());
sum = no2 * no3;
text1.setText(String.valueOf(sum));
}
if (sign.equals("/")) {
int no2 = Integer.parseInt(no1);
int no3 = Integer.parseInt(text1.getText());
sum = no2 / no3;
text1.setText(String.valueOf(sum));
}
}
});
buttons[15].setBounds(190, 200, 50, 40);
buttons[15].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sb.delete(0, sb.capacity());//清除sb的内容
text1.setText("");//结果框设置为空
}
});
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//响应关闭窗口
setVisible(true);//显示窗口
}
}
2.主程序类
package Calc;
public class CalcTest {
public static void main(String[] args) {
CalcFrame f = new CalcFrame();
}
}
/*
* @(#)JCalculator.java 1.00 06/17/2015
*/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
* A simple calculator program.
* <p>I saw this program in a QQ group, and help a friend correct it.</p>
*
* @author Singyuen Yip
* @version 1.00 12/29/2009
* @see JFrame
* @see ActionListener
*/
public class JCalculator extends JFrame implements ActionListener {
/**
* Serial Version UID
*/
private static final long serialVersionUID = -169068472193786457L;
/**
* This class help close the Window.
* @author Singyuen Yip
*
*/
private class WindowCloser extends WindowAdapter {
public void windowClosing(WindowEvent we) {
System.exit(0);
}
}
int i;
// Strings for Digit & Operator buttons.
private final String[] str = { "7", "8", "9", "/", "4", "5", "6", "*","1",
"2", "3", "-", ".", "0", "=", "+" };
// Build buttons.
JButton[] buttons = new JButton[str.length];
// For cancel or reset.
JButton reset = new JButton("CE");
// Build the text field to show the result.
JTextField display = new JTextField("0");
/**
* Constructor without parameters.
*/
public JCalculator() {
super("Calculator");
// Add a panel.
JPanel panel1 = new JPanel(new GridLayout(4, 4));
// panel1.setLayout(new GridLayout(4,4));
for (i = 0; i < str.length; i++) {
buttons[i] = new JButton(str[i]);
panel1.add(buttons[i]);
}
JPanel panel2 = new JPanel(new BorderLayout());
// panel2.setLayout(new BorderLayout());
panel2.add("Center", display);
panel2.add("East", reset);
// JPanel panel3 = new Panel();
getContentPane().setLayout(new BorderLayout());
getContentPane().add("North", panel2);
getContentPane().add("Center", panel1);
// Add action listener for each digit & operator button.
for (i = 0; i < str.length; i++)
buttons[i].addActionListener(this);
// Add listener for "reset" button.
reset.addActionListener(this);
// Add listener for "display" button.
display.addActionListener(this);
// The "close" button "X".
addWindowListener(new WindowCloser());
// Initialize the window size.
setSize(800, 800);
// Show the window.
// show(); Using show() while JDK version is below 1.5.
setVisible(true);
// Fit the certain size.
pack();
}
public void actionPerformed(ActionEvent e) {
Object target = e.getSource();
String label = e.getActionCommand();
if (target == reset)
handleReset();
else if ("0123456789.".indexOf(label) > 0)
handleNumber(label);
else
handleOperator(label);
}
// Is the first digit pressed?
boolean isFirstDigit = true;
/**
* Number handling.
* @param key the key of the button.
*/
public void handleNumber(String key) {
if (isFirstDigit)
display.setText(key);
else if ((key.equals(".")) && (display.getText().indexOf(".") < 0))
display.setText(display.getText() + ".");
else if (!key.equals("."))
display.setText(display.getText() + key);
isFirstDigit = false;
}
/**
* Reset the calculator.
*/
public void handleReset() {
display.setText("0");
isFirstDigit = true;
operator = "=";
}
double number = 0.0;
String operator = "=";
/**
* Handling the operation.
* @param key pressed operator's key.
*/
public void handleOperator(String key) {
if (operator.equals("+"))
number += Double.valueOf(display.getText());
else if (operator.equals("-"))
number -= Double.valueOf(display.getText());
else if (operator.equals("*"))
number *= Double.valueOf(display.getText());
else if (operator.equals("/"))
number /= Double.valueOf(display.getText());
else if (operator.equals("="))
number = Double.valueOf(display.getText());
display.setText(String.valueOf(number));
operator = key;
isFirstDigit = true;
}
public static void main(String[] args) {
new JCalculator();
}
}
运行界面：
说实在的，你写的这个计算器不怎么样。特别是布局。
我给你一个很简单的吧。你自己学习一下。。
import java.awt.*;
import java.awt.event.*;
/**
*
* @author zzj
*
*/
public class Jisuanqi extends WindowAdapter {
Panel p1 = new Panel();
Panel p2 = new Panel();
Panel p3 = new Panel();
TextField txt;
private Button[] b = new Button[17];
private String ss[] = { "7", "8", "9", "+", "4", "5", "6", "-", "1", "2",
"3", "*", "清空", "0", "=", "/", "关闭" };
static double a;
static String s, str;//定义变量 创建对像
public static void main(String args[]) {
(new Jisuanqi()).frame();
}
public void frame() {
Frame fm = new Frame("简单计算器");
for (int i = 0; i <= 16; i++) {
b[i] = new Button(ss[i]);
}
for (int i = 0; i <= 15; i++) {
p2.add(b[i]);
} //创建按钮 并添加到P2
b[16].setBackground(Color.yellow);
txt = new TextField(15);
txt.setEditable(false);
for (int i = 0; i <= 16; i++) {
b[i].addActionListener(new buttonlistener());//添加监听器
}
b[16].addActionListener(new close());
fm.addWindowListener(this);
fm.setBackground(Color.red);
p1.setLayout(new BorderLayout());
p1.add(txt, "North");
p2.setLayout(new GridLayout(4, 4));
p3.setLayout(new BorderLayout());
p3.add(b[16]);
fm.add(p1, "North");
fm.add(p2, "Center");
fm.add(p3, "South");
fm.pack();
fm.setVisible(true);//都是些窗中设置 添加相关组件和监听器
}
public void windowClosing(WindowEvent e) {
System.exit(0);//退出系统
}
class buttonlistener implements ActionListener {//编写监听器事件 通过按键得出给果
public void actionPerformed(ActionEvent e) {
Button btn = (Button) e.getSource();
if (btn.getLabel() == "=") {
jisuan();
str = String.valueOf(a);
txt.setText(str);
s = "";
} else if (btn.getLabel() == "+") {
jisuan();
txt.setText("");
s = "+";
} else if (btn.getLabel() == "-") {
jisuan();
txt.setText("");
s = "-";
} else if (btn.getLabel() == "/") {
jisuan();
txt.setText("");
s = "/";
} else if (btn.getLabel() == "*") {
jisuan();
txt.setText("");
s = "*";
} else {
txt.setText(txt.getText() + btn.getLabel());
if (btn.getLabel() == "清空")
txt.setText("");
}
}
public void jisuan() {//编写具体计算方法
if (s == "+")
a += Double.parseDouble(txt.getText());
else if (s == "-")
a -= Double.parseDouble(txt.getText());
else if (s == "*")
a *= Double.parseDouble(txt.getText());
else if (s == "/")
a /= Double.parseDouble(txt.getText());
else
a = Double.parseDouble(txt.getText());
}
}
}
class close implements ActionListener {//退出
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
- -|||……虽然我也有计算器的代码，不过我还是给你指正下你的问题出在哪里吧。很无语……
public void actionPerformed(ActionEvent e){
Button0.addActionListener(this);
if(e.getActionCommand().equals("Button1"))
Text1.setText(e.getActionCommand());
}
你应该把这里面的Button0.addActionListener(this);添加到Calculator类函数中.因为你是在Calculator类中触发了按钮事件，然后在actionPerformed(ActionEvent e)函数中处理它。你把它放到actionPerformed(ActionEvent e)函数中，又怎么能触发事件呢……
你修改看看吧，这样应该就可以用了
将Button0.addActionListener(this);移到Calculator（）函数，并将按键处理代码修改如下即可正常运行
public void actionPerformed(ActionEvent e){
if(e.getSource()== Button0)
Text1.setText(Button0.getLabel());
}
}
Button0.addActionListener(this);
if(e.getActionCommand().equals("Button1"))
Text1.setText(e.getActionCommand());
}
注意你equals的对象不是Button0！
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答：private String operator = "="; //当前运算的运算符 private boolean firstDigit = true; // 标志用户按的是否是整个表达式的第一个数字,或者是运算符后的第一个数字 private double resultNum = 0.0; // 计算的中间结果 private boolean operateValidFlag = true; //判断操作是否合法 public ...
如何使用Java对象语言编写一个加减乘除计算器要有代码
答：下面文件名要为：JiSuanQi.java import java.awt.*;import java.awt.event.*;public class JiSuanQi { String s="",s1=null,s2=null;Frame f=new Frame("计算器");TextField tf=new TextField(30);Panel p1=new Panel();Panel p2=new Panel();Panel p3=new Panel();Button bt1=new ...
Java程序编写一个计算器类,要求实现加、减、乘、除运算,注意在进行除 ...
答：JButton bCancel; //清除按钮private JButton[] b=new JButton[16]; //构造按钮数组private char LastOp; //操作符号private boolean Countable; //用于判断是否可计算private String KeyLabel[]={"7","8","9","/","4","5","6","*","1","2","3","-","0","."...
用Java 写一个两个整数相加的程序
答：代码如下：public class Test { public static int add(int a,int b){ return a+b;} public static void main(String args[]){ Scanner scanner = new Scanner(System.in);System.out.println("请输入第一个数");int a = scanner.nextInt();System.out.println("请输入第二个数");int b...
