本程序寫于剛剛學習j2se的swing時，記得課堂上老師說起，他們那會兒畢業找工作，能夠寫出個計算器就算是會寫程序的人，就不愁找不到工作了，于是我就寫了這個程序，安慰一下失業不久的自己。回想起來，這個東西還是挺能夠鍛煉邏輯思維的，當初確實是費了不少心思，界面就可以看到，懶這個鍵是調用Windows系統的計算器，當初就是一步步照它而完成的，當然這個程序并沒有實現科學計算。由于程序是剛剛系統學習編程不久時寫的，很多地方存在不規范，而且一些地方繞了彎子，諸如界面按鈕的定義并不是采用數組而成，而是手工畫上去的，再有就是java監聽器的使用。
以下為運行效果圖：
以下為程序源代碼：
package calculate;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.io.*;
/** *//**
* <p>Title: 簡單計算器</p>
*
* <p>Description: </p>
*
* <p>Copyright: Copyright (c) 2007</p>
*
* <p>Company: 無業游民</p>
*
* @author 非凡DZ
* @version 1.0
*/
public class FrameCalculate extends JFrame 
{
private String front = "", behind = ""; //分別用于記錄加減乘除運算符之前,之后輸入的內容
private String op; //用于記錄運算符
private String re;//用于存儲運算結果的字符串格式
private boolean flag = false; //用于記錄是否按下了運算符
private boolean flag1 = false;//用于判斷是否輸入了點運算符
private double result;//用于存儲運算結果
private boolean flag2 = false;//用于判斷是否輸入了數字
private boolean flag3 = false;//用于判斷是否按下了等號運算符
JPanel contentPane;
JTextField txtResult = new JTextField();
JButton btnNull = new JButton();
JButton btnFour = new JButton();
JButton btnFive = new JButton();
JButton btnSix = new JButton();
JButton btnDecrease = new JButton();
JButton btnBegin = new JButton();
JButton btnOne = new JButton();
JButton btnTwo = new JButton();
JButton btnThree = new JButton();
JButton btnMultiply = new JButton();
JButton btnCancel = new JButton();
JButton btnZero = new JButton();
JButton btnMinus = new JButton();
JButton btnPoint = new JButton();
JButton btnDivide = new JButton();
JButton btnEqual = new JButton();
JButton btnIncrease = new JButton();
JButton btnSeven = new JButton();
JButton btnEight = new JButton();
JButton btnNine = new JButton();
public FrameCalculate() {
try {
setDefaultCloseOperation(EXIT_ON_CLOSE);
jbInit();
} catch (Exception exception) {
exception.printStackTrace();
}
}
/** *//**
* Component initialization.
*
* @throws java.lang.Exception
*/
private void jbInit() throws Exception {
contentPane = (JPanel) getContentPane();
contentPane.setLayout(null);
this.setResizable(false);
setSize(new Dimension(400, 300));
setTitle("計算器");
txtResult.setEnabled(false);
txtResult.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
txtResult.setEditable(false);
txtResult.setText("0");
txtResult.setHorizontalAlignment(SwingConstants.RIGHT);
txtResult.setBounds(new Rectangle(33, 19, 310, 34));
btnNull.setBounds(new Rectangle(298, 70, 46, 37));
btnNull.setFont(new java.awt.Font("Dialog", Font.PLAIN, 12));
btnNull.setText("懶");
btnNull.addActionListener(new FrameCalculate_btnNull_actionAdapter(this));
btnFour.setBounds(new Rectangle(33, 120, 46, 37));
btnFour.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnFour.setText("4");
btnFive.setBounds(new Rectangle(101, 120, 46, 37));
btnFive.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnFive.setText("5");
btnSix.setBounds(new Rectangle(167, 119, 46, 37));
btnSix.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnSix.setText("6");
btnDecrease.setBounds(new Rectangle(234, 120, 46, 37));
btnDecrease.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnDecrease.setText("-");
btnBegin.setBounds(new Rectangle(298, 121, 46, 37));
btnBegin.setFont(new java.awt.Font("Dialog", Font.PLAIN, 15));
btnBegin.setText("C");
btnBegin.addActionListener(new FrameCalculate_btnBegin_actionAdapter(this));
btnOne.setBounds(new Rectangle(33, 172, 46, 37));
btnOne.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnOne.setText("1");
btnTwo.setBounds(new Rectangle(101, 172, 46, 37));
btnTwo.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnTwo.setText("2");
btnThree.setBounds(new Rectangle(167, 172, 46, 37));
btnThree.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnThree.setText("3");
btnMultiply.setBounds(new Rectangle(234, 172, 46, 37));
btnMultiply.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnMultiply.setText("*");
btnCancel.setBounds(new Rectangle(298, 172, 46, 37));
btnCancel.setFont(new java.awt.Font("Dialog", Font.PLAIN, 12));
btnCancel.setText("←");
btnCancel.addActionListener(new FrameCalculate_btnCancel_actionAdapter(this));
btnZero.setBounds(new Rectangle(33, 222, 46, 37));
btnZero.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnZero.setText("0");
//加載數字0-9的監聽事件
btnZero.addActionListener(new FrameCalculate_btnZero_actionAdapter(this));
btnOne.addActionListener(new FrameCalculate_btnZero_actionAdapter(this));
btnTwo.addActionListener(new FrameCalculate_btnZero_actionAdapter(this));
btnThree.addActionListener(new FrameCalculate_btnZero_actionAdapter(this));
btnFour.addActionListener(new FrameCalculate_btnZero_actionAdapter(this));
btnFive.addActionListener(new FrameCalculate_btnZero_actionAdapter(this));
btnSix.addActionListener(new FrameCalculate_btnZero_actionAdapter(this));
btnSeven.addActionListener(new FrameCalculate_btnZero_actionAdapter(this));
btnEight.addActionListener(new FrameCalculate_btnZero_actionAdapter(this));
btnNine.addActionListener(new FrameCalculate_btnZero_actionAdapter(this));
btnMinus.setBounds(new Rectangle(101, 222, 46, 37));
btnMinus.setFont(new java.awt.Font("Dialog", Font.PLAIN, 10));
btnMinus.setText("+/-");
btnMinus.addActionListener(new FrameCalculate_btnMinus_actionAdapter(this));
btnPoint.setBounds(new Rectangle(167, 222, 46, 37));
btnPoint.setFont(new java.awt.Font("Dialog", Font.PLAIN, 30));
btnPoint.setHorizontalTextPosition(SwingConstants.CENTER);
btnPoint.setText(".");
btnPoint.addActionListener(new FrameCalculate_btnPoint_actionAdapter(this));
btnDivide.setBounds(new Rectangle(234, 222, 46, 37));
btnDivide.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnDivide.setText("/");
btnEqual.setBounds(new Rectangle(298, 222, 46, 37));
btnEqual.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnEqual.setText("=");
btnEqual.addActionListener(new FrameCalculate_btnEqual_actionAdapter(this));
btnIncrease.setBounds(new Rectangle(234, 70, 46, 37));
btnIncrease.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnIncrease.setText("+");
//加載加減乘除運算符的監聽事件
btnIncrease.addActionListener(new
FrameCalculate_btnIncrease_actionAdapter(this));
btnDecrease.addActionListener(new
FrameCalculate_btnIncrease_actionAdapter(this));
btnMultiply.addActionListener(new
FrameCalculate_btnIncrease_actionAdapter(this));
btnDivide.addActionListener(new
FrameCalculate_btnIncrease_actionAdapter(this));
btnSeven.setBounds(new Rectangle(33, 70, 46, 37));
btnSeven.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnSeven.setText("7");
btnEight.setBounds(new Rectangle(101, 70, 46, 37));
btnEight.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnEight.setText("8");
btnNine.setBounds(new Rectangle(167, 70, 46, 37));
btnNine.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
btnNine.setText("9");
contentPane.add(btnFive);
contentPane.add(btnSix);
contentPane.add(btnDecrease);
contentPane.add(btnBegin);
contentPane.add(btnOne);
contentPane.add(btnTwo);
contentPane.add(btnThree);
contentPane.add(btnMultiply);
contentPane.add(btnCancel);
contentPane.add(btnMinus);
contentPane.add(btnPoint);
contentPane.add(btnDivide);
contentPane.add(btnEqual);
contentPane.add(btnEight);
contentPane.add(btnNine);
contentPane.add(btnFour);
contentPane.add(btnSeven);
contentPane.add(btnIncrease);
contentPane.add(btnNull);
contentPane.add(txtResult);
contentPane.add(btnZero);
}
public void btnNull_actionPerformed(ActionEvent e) {
try {
Runtime.getRuntime().exec("calc.exe"); //調用系統的計算器
} catch (IOException ex) {
}
}
public void btnZero_actionPerformed(ActionEvent e) {
if (flag) { //如果剛剛按下了運算符
txtResult.setText("");
if (flag1) {//判斷之前是否輸入了點運算符
txtResult.setText("0." + e.getActionCommand());
flag1 = false;
} else {
txtResult.setText(e.getActionCommand());
}
flag2 = true;
} else {
int num = txtResult.getText().indexOf(".");
if (num < 0 && !txtResult.getText().equals("0")) {
txtResult.setText(txtResult.getText() + e.getActionCommand());
} else if (num < 0 && txtResult.getText().equals("0")) {
txtResult.setText(e.getActionCommand());
} else if (num >= 0 && txtResult.getText().equals("0")) {
txtResult.setText("0." + e.getActionCommand());
} else if (num >= 0 && !txtResult.getText().equals("0")) {
txtResult.setText(txtResult.getText() + e.getActionCommand());
}
}
flag = false;
flag3=false;
}
public void btnIncrease_actionPerformed(ActionEvent e) {
if(flag3){
txtResult.setText(txtResult.getText());
op = e.getActionCommand(); //得到剛剛按下的運算符
front = txtResult.getText(); //記錄加減乘除運算符之前輸入的內容
}
else if (flag2) {
ActionEvent ee = new ActionEvent("qq", 1, "pp");
btnEqual_actionPerformed(ee);
op = e.getActionCommand(); //得到剛剛按下的運算符
front = re;
flag2 = false;
} else {
front = txtResult.getText(); //記錄加減乘除運算符之前輸入的內容
op = e.getActionCommand(); //得到剛剛按下的運算符
}
flag3=false;
flag = true; //記錄已經按下了加減乘除運算符的其中一個
}
public void btnEqual_actionPerformed(ActionEvent e) {
if(!flag3)//未曾按下等于運算符
behind = txtResult.getText();
else
front = re;
try {
double a1 = Double.parseDouble(front);
double b1 = Double.parseDouble(behind);
if (op == "+") {
result = a1 + b1;
} else if (op == "-") {
result = a1 - b1;
} else if (op == "*") {
result = a1 * b1;
} else {
result = a1 / b1;
}
Double r = new Double(result);
re = r.toString(result);
txtResult.setText(re);
} catch (ArithmeticException ce) {
txtResult.setText("除數不能為零");
} catch (Exception ee) {
}
if (!flag3)
flag3 = true;
}
public void btnPoint_actionPerformed(ActionEvent e) {
int num=txtResult.getText().indexOf(".");
if(num<0 && !flag)
txtResult.setText(txtResult.getText()+e.getActionCommand());
if(flag)
flag1=true;
}
public void btnBegin_actionPerformed(ActionEvent e) {
flag=false;
flag1=false;
flag2=false;
flag3=false;
front="";
behind="";
re="";
txtResult.setText("0");
}
public void btnMinus_actionPerformed(ActionEvent e) {//取反運算符事件處理
if(txtResult.getText().equals("0")){//如果文本框內容為0
txtResult.setText(txtResult.getText());
}else if(txtResult.getText().indexOf("-")>=0){//若文本框中含有負號
String a=txtResult.getText().replaceAll("-","");
txtResult.setText(a);
}else if(flag){
txtResult.setText("0");
}else{
txtResult.setText("-"+txtResult.getText());
}
}
public void btnCancel_actionPerformed(ActionEvent e) {//退格事件處理方法
String str=txtResult.getText();
if(str.length() == 1){//如文本框中只剩下最后一個字符,將文本框內容置為0
txtResult.setText("0");
}
if(str.length()>1){
str=str.substring(0,str.length()-1);
txtResult.setText(str);
}
}
public static void main(String[] args){
FrameCalculate fc = new FrameCalculate();
fc.setSize(400,310);
fc.setLocation(200,150);
fc.setVisible(true);
}
}
class FrameCalculate_btnCancel_actionAdapter implements ActionListener {
private FrameCalculate adaptee;
FrameCalculate_btnCancel_actionAdapter(FrameCalculate adaptee) {
this.adaptee = adaptee;
}
public void actionPerformed(ActionEvent e) {
adaptee.btnCancel_actionPerformed(e);
}
}
class FrameCalculate_btnMinus_actionAdapter implements ActionListener {
private FrameCalculate adaptee;
FrameCalculate_btnMinus_actionAdapter(FrameCalculate adaptee) {
this.adaptee = adaptee;
}
public void actionPerformed(ActionEvent e) {
adaptee.btnMinus_actionPerformed(e);
}
}
class FrameCalculate_btnBegin_actionAdapter implements ActionListener {
private FrameCalculate adaptee;
FrameCalculate_btnBegin_actionAdapter(FrameCalculate adaptee) {
this.adaptee = adaptee;
}
public void actionPerformed(ActionEvent e) {
adaptee.btnBegin_actionPerformed(e);
}
}
class FrameCalculate_btnPoint_actionAdapter implements ActionListener {
private FrameCalculate adaptee;
FrameCalculate_btnPoint_actionAdapter(FrameCalculate adaptee) {
this.adaptee = adaptee;
}
public void actionPerformed(ActionEvent e) {
adaptee.btnPoint_actionPerformed(e);
}
}
class FrameCalculate_btnEqual_actionAdapter implements ActionListener {
private FrameCalculate adaptee;
FrameCalculate_btnEqual_actionAdapter(FrameCalculate adaptee) {
this.adaptee = adaptee;
}
public void actionPerformed(ActionEvent e) {
adaptee.btnEqual_actionPerformed(e);
}
}
class FrameCalculate_btnIncrease_actionAdapter implements ActionListener {
private FrameCalculate adaptee;
FrameCalculate_btnIncrease_actionAdapter(FrameCalculate adaptee) {
this.adaptee = adaptee;
}
public void actionPerformed(ActionEvent e) {
adaptee.btnIncrease_actionPerformed(e);
}
}
class FrameCalculate_btnZero_actionAdapter implements ActionListener {
private FrameCalculate adaptee;
FrameCalculate_btnZero_actionAdapter(FrameCalculate adaptee) {
this.adaptee = adaptee;
}
public void actionPerformed(ActionEvent e) {
adaptee.btnZero_actionPerformed(e);
}
}
class FrameCalculate_btnNull_actionAdapter implements ActionListener {
private FrameCalculate adaptee;
FrameCalculate_btnNull_actionAdapter(FrameCalculate adaptee) {
this.adaptee = adaptee;
}
public void actionPerformed(ActionEvent e) {
adaptee.btnNull_actionPerformed(e);
}
}