JAVA 编写计算器 要代码最简单的

如题所述

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.=/";
ArrayList<String> arrayList = new ArrayList<String>();//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;i<allButtons.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;i<allButtons.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;i<allButtons.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 ArrayList<String> getResult(ArrayList<String> list){
String res = null;
String[] s = {"/","*","-","+"};
int i=0;
if(list.size()>1){
for(;i<s.length;){
if(s[i].equals("/")){
for(int j=0;j<list.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;j<list.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;j<list.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;j<list.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;k<c.length;k++){
c[k] = res.charAt(k);
}
for(int k=0;k<c.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();
}
}

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