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窗体写好了，运算你自己写
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import java.awt.Button;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class SimpleCalculator {
private JFrame f = new JFrame();
private JPanel firstPanel = new JPanel();
private JLabel firstNumLabel = new JLabel("第一个数字");
private JTextField number1 = new JTextField();
private JPanel secondPanel = new JPanel();
private Button add = new Button("+");
private Button mul = new Button("*");
private Button clear = new Button("清除");
private JPanel thirdPanel = new JPanel();
private JLabel resultLabel = new JLabel("结果为");
private JTextField result = new JTextField();
public SimpleCalculator(){
firstPanel.setLayout(new GridLayout(1, 2));
firstPanel.add(firstNumLabel);
firstPanel.add(number1);
secondPanel.setLayout(new GridLayout(1, 3));
secondPanel.add(add);
secondPanel.add(mul);
secondPanel.add(clear);
thirdPanel.setLayout(new GridLayout(1, 2));
thirdPanel.add(resultLabel);
thirdPanel.add(result);
f.add(new JLabel("简易计算器"));
f.add(firstPanel);
f.add(secondPanel);
f.add(thirdPanel);
f.setLayout(new GridLayout(4, 1));
f.setVisible(true);
f.pack();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
new SimpleCalculator();
}
}
package importantpg;
import java.awt.*;
import java.awt.event.*;
public class jisuanqi
{
TextArea tf=new TextArea(3,50 );
Button lb=new Button("clear");
Panel p1=new Panel();
Panel p2=new Panel();
public jisuanqi()
{ Frame f=new Frame("计算器");
Panel p=new Panel();
f.setBackground(Color.white);
f.setSize(500, 1500);
f.setVisible(true);
f.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e) {System.exit(1);}
});
Button[] b=new Button[18]; b[10]=new Button("-"); b[15]=new Button("(");
b[11]=new Button("+"); b[12]=new Button("*"); b[16]=new Button(")");
b[13]=new Button("/"); b[14]=new Button("="); b[17]=new Button("退格");
for(int i=0;i=9;++i)
{
b[i]=new Button(""+i);
}
p.setLayout(new GridLayout(6,3));
avent aa=new avent();
lb.addActionListener(aa);
for(int i=0;i18;++i)
{
p.add(b[i]);b[i].addActionListener(aa);
}
p1.setLayout(new BorderLayout());
p1.add(lb,"North");p1.add(tf,"South");f.add(p1, "South");
f.add(p,"Center"); f.pack();
} //构造方法
public static void main(String args[])
{
new jisuanqi();
}
class avent implements ActionListener //事件体
{
public void actionPerformed(ActionEvent e)
{
String s=null; String in="";
s=e.getActionCommand();
if (s!="="s!=nulls!="clear"s!="退格")
{
tf.append(s);
in+=s; s=null;
}
else if(s=="clear")
{
tf.replaceRange("",0,1000);
}else if(s=="=")
{
tf.append("="+jisuan(tf.getText()));
}
else if(s=="退格") {}
}///////////////////////////////////////////////事件处理方法
}
///////////////////////////////////////计算过程//////////////
static String jisuan(String s)
{
String hs= "";
char[] ch = new char[s.length()];
int top = -1;
for (int i = 0; i s.length(); i++)
{
char rsc = s.charAt(i);
switch(rsc)
{
case ' ' : break;
case '+' : //操作符
case '-' :
while (top = 0) //栈不为空时
{
char pc = ch[top--]; //pop Operator
if (pc == '(')
{
ch[++top] = pc; //push Operator
break;
}
else {hs = hs + pc;}
}
ch[++top] = rsc; //push Operator
hs += " ";break;
case '*' : //操作符
case '/' :
while (top = 0) //栈不为空时
{
char c = ch[top--]; //pop Operator
if (c == '(')
{
ch[++top] = c; //push Operator
break;
}
else
{
if (c == '+' || c == '-')
{
ch[++top] = c; //push Operator
break;
}
else
{
hs = hs + c;
}
}
}
ch[++top] = rsc; //push Operator
hs += " ";
break;
case '(' : //操作符
ch[++top] = rsc;
hs+= " ";
break;
case ')' : //操作符
while (top = 0) //栈不为空时
{
char c = ch[top--]; //pop Operator
if (c == '(')
{
break;
}
else
{
hs= hs + c;
}
}
hs += " ";
break;
default : //操作数
hs= hs + rsc;
break;
}//switch
}/////////////////////////////for
while (top = 0)
{
hs= hs + ch[top--]; //pop Operator
}
//System.out.println("hs="+hs); //后缀
//////////////////////////////////////////////后缀////////////////////////////////////
//后缀表达式计算
double[] result = new double[hs.length()];
double x, y;
top = - 1;
String st = "";
for (int i = 0; i hs.length(); i++)
{
char c = hs.charAt(i);
if ((c = '0' c = '9') || c == '.')
{
st += c;
}
if ((c == ' ' st != "") || i == hs.length() - 1)
{
result[++top] = Double.parseDouble(st) ; //push Operands
st = "";
}
if (c == '+' || c == '-' || c == '*' || c == '/')
{
if ((st != ""))
{
result[++top] =Double.parseDouble(st) ; //push Operands
st = "";
}
y = result[top--];
x = result[top--];
switch (c)
{
case '+' :
result[++top] = x+y;break;//push 中间结果再次入栈
case '-' :
result[++top] = x-y;break;
case '*' :
result[++top] = x*y;break;
case '/' :
result[++top] = x/y;break;
default :break;
}
}////////////////////if
} ///////////////////////for
return String.valueOf(result[top]); //pop 最终结果
} /////////////////////////jisuan
}
这段代码对你有帮助
import javax.swing.*;
import javax.swing.border.Border;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.HashMap;
/**
* 我的计算器。MyCalculator 继承于 JFrame，是计算器的界面
*/
public class MyCalculator extends JFrame {
private Border border = BorderFactory.createEmptyBorder(5, 5, 5, 5);
private JTextField textbox = new JTextField("0");
private CalculatorCore core = new CalculatorCore();
private ActionListener listener = new ActionListener() {
public void actionPerformed(ActionEvent e) {
JButton b = (JButton) e.getSource();
String label = b.getText();
String result = core.process(label);
textbox.setText(result);
}
};
public MyCalculator(String title) throws HeadlessException {
super(title); // 调用父类构造方法
setupFrame(); // 调整窗体属性
setupControls(); // 创建控件
}
private void setupControls() {
setupDisplayPanel(); // 创建文本面板
setupButtonsPanel(); // 创建按钮面板
}
// 创建按钮面板并添加按钮
private void setupButtonsPanel() {
JPanel panel = new JPanel();
panel.setBorder(border);
panel.setLayout(new GridLayout(4, 5, 3, 3));
createButtons(panel, new String[]{
"7", "8", "9", "+", "C",
"4", "5", "6", "-", "CE",
"1", "2", "3", "*", "", // 空字符串表示这个位置没有按钮
"0", ".", "=", "/", ""
});
this.add(panel, BorderLayout.CENTER);
}
/**
* 在指定的面板上创建按钮
*
* @param panel 要创建按钮的面板
* @param labels 按钮文字
*/
private void createButtons(JPanel panel, String[] labels) {
for (String label : labels) {
// 如果 label 为空，则表示创建一个空面板。否则创建一个按钮。
if (label.equals("")) {
panel.add(new JPanel());
} else {
JButton b = new JButton(label);
b.addActionListener(listener); // 为按钮添加侦听器
panel.add(b);
}
}
}
// 设置显示面板，用一个文本框来作为计算器的显示部分。
private void setupDisplayPanel() {
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
panel.setBorder(border);
setupTextbox();
panel.add(textbox, BorderLayout.CENTER);
this.add(panel, BorderLayout.NORTH);
}
// 调整文本框
private void setupTextbox() {
textbox.setHorizontalAlignment(JTextField.RIGHT); // 文本右对齐
textbox.setEditable(false); // 文本框只读
textbox.setBackground(Color.white); // 文本框背景色为白色
}
// 调整窗体
private void setupFrame() {
this.setDefaultCloseOperation(EXIT_ON_CLOSE); // 当窗体关闭时程序结束
this.setLocation(100, 50); // 设置窗体显示在桌面上的位置
this.setSize(300, 200); // 设置窗体大小
this.setResizable(false); // 窗体大小固定
}
// 程序入口
public static void main(String[] args) throws Exception {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
MyCalculator frame = new MyCalculator("我的计算器");
frame.setVisible(true); // 在桌面上显示窗体
}
}
/**
* 计算器核心逻辑。这个逻辑只能处理 1~2 个数的运算。
*/
class CalculatorCore {
private String displayText = "0"; // 要显示的文本
boolean reset = true;
private BigDecimal number1, number2;
private String operator;
private HashMapString, Operator operators = new HashMapString, Operator();
private HashMapString, Processor processors = new HashMapString, Processor();
CalculatorCore() {
setupOperators();
setupProcessors();
}
// 为每种命令添加处理方式
private void setupProcessors() {
processors.put("[0-9]", new Processor() {
public void calculate(String command) {
numberClicked(command);
}
});
processors.put("\\.", new Processor() {
public void calculate(String command) {
dotClicked();
}
});
processors.put("=", new Processor() {
public void calculate(String command) {
equalsClicked();
}
});
processors.put("[+\\-*/]", new Processor() {
public void calculate(String command) {
operatorClicked(command);
}
});
processors.put("C", new Processor() {
public void calculate(String command) {
clearClicked();
}
});
processors.put("CE", new Processor() {
public void calculate(String command) {
clearErrorClicked();
}
});
}
// 为每种 operator 添加处理方式
private void setupOperators() {
operators.put("+", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.add(number2);
}
});
operators.put("-", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.subtract(number2);
}
});
operators.put("*", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.multiply(number2);
}
});
operators.put("/", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.divide(number2, 30, RoundingMode.HALF_UP);
}
});
}
// 根据命令处理。这里的命令实际上就是按钮文本。
public String process(String command) {
for (String pattern : processors.keySet()) {
if (command.matches(pattern)) {
processors.get(pattern).calculate(command);
break;
}
}
return displayText;
}
// 当按下 CE 时
private void clearErrorClicked() {
if (operator == null) {
number1 = null;
} else {
number2 = null;
}
displayText = "0";
reset = true;
}
// 当按下 C 时，将计算器置为初始状态。
private void clearClicked() {
number1 = null;
number2 = null;
operator = null;
displayText = "0";
reset = true;
}
// 当按下 = 时
private void equalsClicked() {
calculateResult();
number1 = null;
number2 = null;
operator = null;
reset = true;
}
// 计算结果
private void calculateResult() {
number2 = new BigDecimal(displayText);
Operator oper = operators.get(operator);
if (oper != null) {
BigDecimal result = oper.process(number1, number2);
displayText = result.toString();
}
}
// 当按下 +-*/ 时（这里也可以扩展成其他中间操作符）
private void operatorClicked(String command) {
if (operator != null) {
calculateResult();
}
number1 = new BigDecimal(displayText);
operator = command;
reset = true;
}
// 当按下 . 时
private void dotClicked() {
if (displayText.indexOf(".") == -1) {
displayText += ".";
} else if (reset) {
displayText = "0.";
}
reset = false;
}
// 当按下 0-9 时
private void numberClicked(String command) {
if (reset) {
displayText = command;
} else {
displayText += command;
}
reset = false;
}
// 运算符处理接口
interface Operator {
BigDecimal process(BigDecimal number1, BigDecimal number2);
}
// 按钮处理接口
interface Processor {
void calculate(String command);
}
}
package jisuanqi_new;
import java.awt.*;
import java.awt.event.*;
public class JiSuanQi_new implements ActionListener
{
Panel p1;//声明面板p1
TextField t1;//声明文本行t1
String[] label = {"7","8","9","/","4","5","6","*","1","2","3","-","0",".","=","+"};//声明标签数组label1存放按钮上的标签
Button[] b;//声明按钮数组存放16个按钮
private int i;//声明i以备后用
private String op1 = "0";//运算数备用
private String operator = "+";//运算符备用
private boolean append = false;//备用
public JiSuanQi_new()//构造方法
{
t1=new TextField();//初始化文本行t1
b = new Button[label.length];//初始化按钮数组b
p1=new Panel();//初始化面板p1
p1.setLayout(new GridLayout(4,4,4,4));//使面板选择网格布局管理器以备储存16个按钮（4行4列）
for(int i=0;ib.length;i++)//利用for循环把标签放在按钮上，使每个按钮添加事件监听器，在面板p1上添加上16个按钮
{
b[i] = new Button(label[i]);//把标签依次放在16个按钮上
b[i].addActionListener(this);//使每个按钮添加动作事件监听器
p1.add(b[i]); //分别将按钮添加到面板p1上
}
Frame f=new Frame("计算器1.0");//初始化窗口f,起名字计算器1.0
f.setLayout(new BorderLayout());//为窗口选择边界布局管理器
f.add(BorderLayout.NORTH,t1);//把文本行他添加到窗口的北部
f.add(BorderLayout.CENTER,p1);//把面吧p1添加到窗口的中间
f.addWindowListener(new WindowAdapter(){//给窗口f添加窗口事件监听器
public void windowClosing(WindowEvent eve){//运行窗口关闭方法
System.exit(0);//退出程序
}
});
f.setSize(250, 250);//设置窗口大小
f.setLocation(200,200);
f.setVisible(true);//显示窗口
}
public static void main(String args[])
{
new JiSuanQi_new(); //调用构造方法
}
public void actionPerformed(ActionEvent ae)
{//按钮被操作发生
String comm = ae.getActionCommand();//返回与此动作相关的命令字符串，即：使用者第一次点击的按钮是什么。
if("0123456789".indexOf(comm)!=-1)//如果相关命令字符串为0~9之间的数字则执行
{
if(append){
String temp = t1.getText();//新数字
t1.setText(temp+comm);
}else{ //因为此时append为false执行这个
t1.setText(comm); //将文本行t1设置为相关命令字符串（你按中的按钮代码）
append = true;//此时append=true若继续按按钮若继续按数字的话1.第一次的按话不会改变2.非第一次按得话会覆盖之前按得数字（即缺点：只能进行单个数字的计算）
}
}
else if(("+-*/".indexOf(comm)!=-1))//如果相关命令字符串为+-*/之间的数字则执行
{
//保存
//t1.setText(comm);
op1 = t1.getText();//把第一个数赋值给op1
operator = comm;//把命令字符串赋值给operator
append = false;//此时append为false即若继续按按钮若按数字的话将重复上面的动作，按符号的话将覆盖之前的符号
}
else if("=".equals(comm))//如果按的是=号，则按条件进行下面的运算
{
String op2 = t1.getText();//op2第二个数
double d1 = Double.parseDouble(op1);
double d2 = Double.parseDouble(op2);
if(operator.equals("+")){
d1 = d1 + d2 ;
}else if(operator.equals("-")){
d1 = d1 - d2;
}else if(operator.equals("*")){
d1 = d1 * d2;
}else {
d1 = d1 / d2;
}
t1.setText(d1+"");//显示计算结果
append = false;
}
else if(".".equals(comm))//若是.号继续按
{
String temp = t1.getText();
if(temp.indexOf(".")==-1){
t1.setText(temp+".");
append = true;
}
}
}
}
学java的时候自己编的，很简单，能够连续输入计算式后进行计算
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.NumberFormat;
import java.util.ArrayList;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
/**简易计算器，能够进行简单的计算
*
* @see 2008.12.9
*/
public class CalculatorA
implements ActionListener{
private JFrame frame;
private JTextField field;
private JButton[] allButtons;
private JButton clearButton;
// private JButton backButton;
String result="";//保存结果
StringBuilder sb = new StringBuilder();//保存要进行的计算式
int x = 0; //用来判断上一次的事件类型
String str = "123+456-789*0.=/";
ArrayListString arrayList = new ArrayListString();//保存计算式，通过方法进行运算
public CalculatorA(){
frame = new JFrame("我的计算器v1.1");
frame.setLocation(300,300);
field = new JTextField(25);
allButtons = new JButton[16];
for(int i=0;iallButtons.length;i++){
allButtons[i]= new JButton(str.substring(i,i+1));
}
clearButton = new JButton("CLEAR");
// backButton = new JButton("——");
init();
setFondAndColor();
addEventHander();
}
public void init(){
frame.setLayout(new BorderLayout());
JPanel northPanel = new JPanel();
JPanel centerPanel = new JPanel();
JPanel southPanel = new JPanel();
northPanel.setLayout(new FlowLayout());
centerPanel.setLayout(new GridLayout(4,4));
southPanel.setLayout(new FlowLayout());
northPanel.add(field);
for(int i=0;iallButtons.length;i++){
centerPanel.add(allButtons[i]);
}
southPanel.add(clearButton);
//southPanel.add(backButton);
frame.add(northPanel,BorderLayout.NORTH);
frame.add(centerPanel,BorderLayout.CENTER);
frame.add(southPanel,BorderLayout.SOUTH);
}
//设置输入字体
public void setFondAndColor(){
field.setFont(new Font("宋体",Font.BOLD,24));
field.setBackground(new Color(100,200,200));
field.setForeground(Color.RED);
//设置字体从右起始
field.setHorizontalAlignment(JTextField.RIGHT);
}
public void showMi(){
frame.pack();
frame.setResizable(false);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void addEventHander(){
for(int i=0;iallButtons.length;i++){
allButtons[i].addActionListener(this);
}
clearButton.addActionListener(this);
// backButton.addActionListener(this);
}
@Override
public void actionPerformed(ActionEvent e) {
String str = e.getActionCommand();//取得当前事件返回的值
if("0123456789.".indexOf(str)!=-1){
if(x == 0){ //当x为0时表示还没有进行输入
result=str;
sb.append(str);
field.setText(str);
x = 1;
}
else if(x == 1){
result = result +str;
sb.append(str);
field.setText(result);
x = 1;
}
else if(x == 2){
sb.delete(0,sb.length());
result = result+str;
sb.append(str);
field.setText(result);
x = 1;
}
else if(x == 3){
result = str;
sb.delete(0,sb.length());
arrayList.clear();
field.setText(str);
sb.append(str);
field.setText(str);
x = 1;
}
else if(x == 4){
result ="";
sb.delete(0,sb.length());
arrayList.clear();
result = str;
sb.append(str);
field.setText(str);
x = 1;
}
else{
result = result +str;
sb.append(str);
field.setText(result);
x = 1;
}
}
else if("+*-/".indexOf(str)!=-1){
if(x == 0){
field.setText("");
x = 2;
}
else if(x == 1){
result = result + str;
arrayList.add(sb.toString());
arrayList.add(str);
sb.append(str);
field.setText(result);
x = 2;
}
else if(x == 2){
x = 2;
}
else if(x == 3){
field.setText(result+str);
arrayList.add(result);
arrayList.add(str);
result = result+str;
x = 2;
}
else if(x == 4){
result ="";
sb.delete(0,sb.length());
arrayList.clear();
x = 2;
}
else{
field.setText(result+str);
arrayList.add(result);
arrayList.add(str);
result = result+str;
x = 2;
}
}
else if("=".equals(str)){
if(x == 0){
field.setText("0");
arrayList.clear();
result = "0";
x = 3;
}
else if(x == 1){
try{
arrayList.add(sb.toString());
arrayList = getResult(arrayList);
result = arrayList.get(0);
field.setText(result);
arrayList.clear();
x = 3;
}catch(Exception e1){
field.setText("数据格式异常");
x = 0;
}
}
else if(x == 2){
field.setText("数据格式错误.....");
arrayList.clear();
x = 0;
}
else if(x == 3){
field.setText(result);
x = 3;
}
else if(x == 4){
result ="";
sb.delete(0,sb.length());
arrayList.clear();
x = 3;
}
else {
try{
arrayList.add(sb.toString());
arrayList = getResult(arrayList);
result = arrayList.get(0);
field.setText(result);
arrayList.clear();
x = 3;
}catch(Exception e1){
field.setText("数据格式异常");
x = 0;
}
}
}
else if("CLEAR".equals(str)){
arrayList.clear();
field.setText("0");
arrayList.add("0");
x = 4;
}
else{
if(result.length()1){
result = result.substring(0,result.length()-1);
if(sb.length()0){
sb.delete(sb.length()-1,sb.length());
}
else {
sb.delete(0,1);
}
field.setText(result);
x = 5;
}
else{
result = "";
sb.delete(0,sb.length());
arrayList.clear();
field.setText("0");
x = 0;
}
}
}
public static ArrayListString getResult(ArrayListString list){
String res = null;
String[] s = {"/","*","-","+"};
int i=0;
if(list.size()1){
for(;is.length;){
if(s[i].equals("/")){
for(int j=0;jlist.size();j++){
if(list.get(j).equals(s[i])){
res = Double.toString(Double.parseDouble(list.get(j-1))/Double.parseDouble(list.get(j+1)));
//本地的数据格式
NumberFormat nf = NumberFormat.getInstance();
res = nf.format(Double.parseDouble(res));
res = getChange(res);
list.set(j-1,res);
list.remove(j);
list.remove(j);
getResult(list);
}
}
i++;
}
else if(s[i].equals("*")){
for(int j=0;jlist.size();j++){
if(list.get(j).equals(s[i])){
res = Double.toString(Double.parseDouble(list.get(j-1))*Double.parseDouble(list.get(j+1)));
NumberFormat nf = NumberFormat.getInstance();
res = nf.format(Double.parseDouble(res));
res = getChange(res);
list.set(j-1,res);
list.remove(j);
list.remove(j);
getResult(list);
}
}
i++;
}
else if(s[i].equals("-")){
for(int j=0;jlist.size();j++){
if(list.get(j).equals(s[i])){
res = Double.toString(Double.parseDouble(list.get(j-1))-Double.parseDouble(list.get(j+1)));
NumberFormat nf = NumberFormat.getNumberInstance();
res = nf.format(Double.parseDouble(res));
res = getChange(res);
list.set(j-1,res);
list.remove(j);
list.remove(j);
getResult(list);
}
}
i++;
}
else {
for(int j=0;jlist.size();j++){
if(list.get(j).equals(s[i])){
res = Double.toString(Double.parseDouble(list.get(j-1))+Double.parseDouble(list.get(j+1)));
NumberFormat nf = NumberFormat.getInstance();
res = nf.format(Double.parseDouble(res));
res = getChange(res);
list.set(j-1,res);
list.remove(j);
list.remove(j);
getResult(list);
}
}
i++;
}
}
}
return list;
}
//对数字字符串进行排除不必要符号
public static String getChange(String res){
String s_temp = "";
char[] c = new char[res.length()];
for(int k=0;kc.length;k++){
c[k] = res.charAt(k);
}
for(int k=0;kc.length;k++){
if((c[k]= '0' c[k]= '9')|| c[k] == '.'){
s_temp += c[k];
}
}
return s_temp;
}
public static void main(String[] args){
new CalculatorA().showMi();
}
}
import javax.swing.*;
import javax.swing.border.Border;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.HashMap;
/**
* 我的计算器。Cheshi 继承于 JFrame，是计算器的界面
c*/
public class Cheshi extends JFrame {
private Border border = BorderFactory.createEmptyBorder(5, 5, 5, 5);
private JTextField textbox = new JTextField("0");
private CalculatorCore core = new CalculatorCore();
private ActionListener listener = new ActionListener() {
public void actionPerformed(ActionEvent e) {
JButton b = (JButton) e.getSource();
String label = b.getText();
String result = core.process(label);
textbox.setText(result);
}
};
public Cheshi(String title) throws HeadlessException {
super(title); // 调用父类构造方法
setupFrame(); // 调整窗体属性
setupControls(); // 创建控件
}
private void setupControls() {
setupDisplayPanel(); // 创建文本面板
setupButtonsPanel(); // 创建按钮面板
}
// 创建按钮面板并添加按钮
private void setupButtonsPanel() {
JPanel panel = new JPanel();
panel.setBorder(border);
panel.setLayout(new GridLayout(4, 5, 3, 3));
createButtons(panel, new String[]{
"7", "8", "9", "+", "C",
"4", "5", "6", "-", "CE",
"1", "2", "3", "*", "", // 空字符串表示这个位置没有按钮
"0", ".", "=", "/", ""
});
this.add(panel, BorderLayout.CENTER);
}
/**
* 在指定的面板上创建按钮
*
* @param panel 要创建按钮的面板
* @param labels 按钮文字
*/
private void createButtons(JPanel panel, String[] labels) {
for (String label : labels) {
// 如果 label 为空，则表示创建一个空面板。否则创建一个按钮。
if (label.equals("")) {
panel.add(new JPanel());
} else {
JButton b = new JButton(label);
b.addActionListener(listener); // 为按钮添加侦听器
panel.add(b);
}
}
}
// 设置显示面板，用一个文本框来作为计算器的显示部分。
private void setupDisplayPanel() {
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
panel.setBorder(border);
setupTextbox();
panel.add(textbox, BorderLayout.CENTER);
this.add(panel, BorderLayout.NORTH);
}
// 调整文本框
private void setupTextbox() {
textbox.setHorizontalAlignment(JTextField.RIGHT); // 文本右对齐
textbox.setEditable(false); // 文本框只读
textbox.setBackground(Color.white); // 文本框背景色为白色
}
// 调整窗体
private void setupFrame() {
this.setDefaultCloseOperation(EXIT_ON_CLOSE); // 当窗体关闭时程序结束
this.setLocation(100, 50); // 设置窗体显示在桌面上的位置
this.setSize(300, 200); // 设置窗体大小
this.setResizable(false); // 窗体大小固定
}
// 程序入口
public static void main(String[] args) throws Exception {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
Cheshi frame = new Cheshi("我的计算器");
frame.setVisible(true); // 在桌面上显示窗体
}
}
/**
* 计算器核心逻辑。这个逻辑只能处理 1~2 个数的运算。
*/
class CalculatorCore {
private String displayText = "0"; // 要显示的文本
boolean reset = true;
private BigDecimal number1, number2;
private String operator;
private HashMapString, Operator operators = new HashMapString, Operator();
private HashMapString, Processor processors = new HashMapString, Processor();
CalculatorCore() {
setupOperators();
setupProcessors();
}
// 为每种命令添加处理方式
private void setupProcessors() {
processors.put("[0-9]", new Processor() {
public void calculate(String command) {
numberClicked(command);
}
});
processors.put("\\.", new Processor() {
public void calculate(String command) {
dotClicked();
}
});
processors.put("=", new Processor() {
public void calculate(String command) {
equalsClicked();
}
});
processors.put("[+\\-*/]", new Processor() {
public void calculate(String command) {
operatorClicked(command);
}
});
processors.put("C", new Processor() {
public void calculate(String command) {
clearClicked();
}
});
processors.put("CE", new Processor() {
public void calculate(String command) {
clearErrorClicked();
}
});
}
// 为每种 operator 添加处理方式
private void setupOperators() {
operators.put("+", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.add(number2);
}
});
operators.put("-", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.subtract(number2);
}
});
operators.put("*", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.multiply(number2);
}
});
operators.put("/", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.divide(number2, 30, RoundingMode.HALF_UP);
}
});
}
// 根据命令处理。这里的命令实际上就是按钮文本。
public String process(String command) {
for (String pattern : processors.keySet()) {
if (command.matches(pattern)) {
processors.get(pattern).calculate(command);
break;
}
}
return displayText;
}
// 当按下 CE 时
private void clearErrorClicked() {
if (operator == null) {
number1 = null;
} else {
number2 = null;
}
displayText = "0";
reset = true;
}
// 当按下 C 时，将计算器置为初始状态。
private void clearClicked() {
number1 = null;
number2 = null;
operator = null;
displayText = "0";
reset = true;
}
// 当按下 = 时
private void equalsClicked() {
calculateResult();
number1 = null;
number2 = null;
operator = null;
reset = true;
}
// 计算结果
private void calculateResult() {
number2 = new BigDecimal(displayText);
Operator oper = operators.get(operator);
if (oper != null) {
BigDecimal result = oper.process(number1, number2);
displayText = result.toString();
}
}
// 当按下 +-*/ 时（这里也可以扩展成其他中间操作符）
private void operatorClicked(String command) {
if (operator != null) {
calculateResult();
}
number1 = new BigDecimal(displayText);
operator = command;
reset = true;
}
// 当按下 . 时
private void dotClicked() {
if (displayText.indexOf(".") == -1) {
displayText += ".";
} else if (reset) {
displayText = "0.";
}
reset = false;
}
// 当按下 0-9 时
private void numberClicked(String command) {
if (reset) {
displayText = command;
} else {
displayText += command;
}
reset = false;
}
// 运算符处理接口
interface Operator {
BigDecimal process(BigDecimal number1, BigDecimal number2);
}
// 按钮处理接口
interface Processor {
void calculate(String command);
}
}