一、实验目的:
1.掌握软件开发的基本流程
2.掌握常用的软件开发方式和工具。
二、实验内容：
1.设计一个包含登录界面的计算器软件，该软件可以实现第一次作业中的全部功能，同时可以保存用户的历史计算记录。
三、实验步骤：
1、登录代码：
"User.java"
package package1;
import java.awt.*;
import java.awt.event.ActionListener;
import javax.swing.*;
public class User {
public void init(){
System.out.println ("User");
//界面
JFrame jf = new JFrame ("计算机登录界面");
jf.setSize (400, 400);//窗体大小
jf.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);//窗体关闭方式
jf.setLocationRelativeTo (null);// 居中
jf.setLayout (new FlowLayout ());
ImageIcon imgIcon = new ImageIcon ("src/login/111.png");//图标对象
JLabel imgjla = new JLabel (imgIcon);//把图片显示在一个标签里面
JLabel accountjla = new JLabel ("账号: ");
JTextField accountjtf = new JTextField (36);// 36个字符宽度
JLabel passwordjla = new JLabel ("密码: ");
JPasswordField passwordjpf = new JPasswordField (36);// 36个字符宽度
JButton loginjbt = new JButton ("登录");
JButton registjbt = new JButton ("注册");
jf.add (imgjla);
jf.add (accountjla);
jf.add (accountjtf);
jf.add (passwordjla);
jf.add (passwordjpf);
jf.add (loginjbt);
jf.add (registjbt);
jf.setVisible (true);
UIListener uiListener = new UIListener ();
loginjbt.addActionListener ((ActionListener) uiListener);
registjbt.addActionListener ((ActionListener) uiListener);
uiListener.accountjtf = accountjtf;
uiListener.passwordjpf = passwordjpf;
}
public static void main(String[] args){
new User ().init ();
}
}
"UIListerner.java"
package package1;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
public class UIListener {
public JTextField accountjtf;
public JPasswordField passwordjpf;
}
2、计算机登录界面运行结果
3、计算器代码
package 计算器;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.HashMap;
import java.util.Stack;
public class MainWindow extends JFrame {
private JTextArea result;
private JTextArea history_result;
private final int btn_nums = 20;
private final JButton[] btn_sets = new JButton[btn_nums];
private boolean done = true;
public MainWindow(){
super("计算器");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Image img = Toolkit.getDefaultToolkit().getImage("title.png");//窗口图标
setIconImage(img);
String lookAndFeel = UIManager.getSystemLookAndFeelClassName();
try {
UIManager.setLookAndFeel(lookAndFeel);
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException e1) {
e1.printStackTrace();
}
setLayout(new GridLayout(1,2,2,0));
JPanel workSpace = new JPanel();
workSpace.setBackground(Color.white);
add(workSpace);
JPanel historySpace = new JPanel();
historySpace.setBackground(Color.white);
add(historySpace);
//上边显示结果的区域
workSpace.setLayout(new BorderLayout());
result = new JTextArea(8,10);
result.setFont(new Font("微软雅黑",Font.BOLD,25));
result.setEditable(false);
result.setLineWrap(true);
workSpace.add(result, BorderLayout.NORTH);
//下边按钮区域
JPanel btnPanel = new JPanel();
btnPanel.setLayout(new GridLayout(5,4));
for(int i = 0; i < btn_nums; i++) {
String[] btn_text = {
"(", ")", "C", "÷",
"7", "8", "9", "x",
"4", "5", "6", "-",
"1", "2", "3", "+",
"±", "0", ".", "="
};
btn_sets[i] = new JButton(btn_text[i]);
btn_sets[i].addActionListener(new ButtonMonitor());
btn_sets[i].setFont(new Font("微软雅黑",Font.PLAIN,20));
btn_sets[i].setFocusable(false);
btnPanel.add(btn_sets[i]);
}
workSpace.add(btnPanel);
//右边历史区域
historySpace.setLayout(new BorderLayout());
JLabel history_title = new JLabel("历史记录");
history_title.setFont(new Font("微软雅黑",Font.BOLD,20));
historySpace.add(history_title, BorderLayout.NORTH);
JButton clear_all = new JButton("clear all");
clear_all.setFont(new Font("微软雅黑",Font.BOLD,15));
clear_all.setFocusable(false);
clear_all.addActionListener(e -> history_result.setText(""));
history_result = new JTextArea();
history_result.setFont(new Font("微软雅黑",Font.BOLD,20));
history_result.setEditable(false);
history_result.setLineWrap(true);
JScrollPane history_scroll = new JScrollPane(history_result);
historySpace.add(history_scroll, BorderLayout.CENTER);
setSize(800,600);
setMinimumSize(new Dimension(800,600));
setLocationRelativeTo(null);//显示在屏幕中央
setFocusable(true);
setVisible(true);
}
public static void main(String[] args){
MainWindow wnd = new MainWindow();
// String exp = "((1+2x4)÷3-2)÷(1-1)";
// exp = "(9x5)";
// ExpRes res = wnd.calculateExp(exp);
// System.out.println(res.tag + " " + res.msg + " " + res.res);
}
private void addNegative(){
String exp = result.getText();
//添加负号
int ptr = exp.length()-1;
while (ptr >= 0 && exp.charAt(ptr) >= 48 && exp.charAt(ptr) <= 57){
ptr--;
}
String tmp = exp.substring(0, ptr+1) + "(" + "-" + exp.substring(ptr+1) + ")";
result.setText(tmp);
}
private boolean checkLegality(char pre_char, char this_char){
//pre_char为前一个位置的字符，this_char为当前输入的字符
switch (this_char) {
case '(' -> {
return pre_char == ' ' || pre_char == '(' || pre_char == '+' || pre_char == '-' ||
pre_char == 'x' || pre_char == '÷';
}
case ')', '+', '-', 'x', '÷' -> {
return pre_char == ')' || (pre_char >= 48 && pre_char <= 57);
}
case '.', '_' -> {
return pre_char >= 48 && pre_char <= 57;
}
default -> {
return pre_char == ' ' || pre_char == '.' || pre_char == '(' || pre_char == '+' || pre_char == '-' ||
pre_char == 'x' || pre_char == '÷' || (pre_char >= 48 && pre_char <= 57);
}
}
}
private int checkPriority(char a, char b){
//检查运算符a和b的优先级,a为符号栈栈顶运算符，b为待插入运算符
int[][] priority = new int[][]{
/* + */{-1, -1, 1, 1},
/* - */{-1, -1, 1, 1},
/* x */{-1, -1, -1, -1},
/* ÷ */{-1, -1, -1, -1},
/* ( */{1, 1, 1, 1}};
/* + - x ÷ */
HashMap<Character, Integer> char2idx = new HashMap<>();
char2idx.put('+', 0);
char2idx.put('-', 1);
char2idx.put('x', 2);
char2idx.put('÷', 3);
char2idx.put('(', 4);
return priority[char2idx.get(a)][char2idx.get(b)];
}
private void getResult(){
String exp = result.getText();
ExpRes expRes = calculateExp(exp);
int res_int = (int)expRes.res;
String res_str = "";
if(expRes.tag.equals("OK")){
if(expRes.res == 0) res_str += "0";
else{
if(expRes.res/res_int != 1){
res_str += expRes.res;
}else{
res_str += res_int;//去掉整数结果后面的小数
}
}
}
System.out.println(expRes.tag + " " + expRes.msg + " " + expRes.res);
if(expRes.tag.equals("OK")){
result.setText(exp + " =\n" + res_str);
String old_history = history_result.getText();
history_result.setText(old_history + exp + " =\n" + res_str + "\n\n");
}else if(expRes.tag.equals("ERROR")){
result.setText(exp + "\n" + expRes.tag + " : " + expRes.msg);
}
done = true;
}
private ExpRes calculateExp(String exp){
//计算表达式的值
Stack<Character> operatorStack = new Stack<>();
Stack<Double> numberStack = new Stack<>();
int ptr = 0;
while(ptr != exp.length()){
char cur = exp.charAt(ptr++);
if(cur >= 48 && cur <= 57){//当前字符为数字
String numBuffer = "" + cur;
while(ptr < exp.length() && ((exp.charAt(ptr) >= 48 && exp.charAt(ptr) <= 57) || exp.charAt(ptr) == '.')){
numBuffer += exp.charAt(ptr++);
}
double value = Double.parseDouble(numBuffer);
numberStack.add(value);
}else if(cur == '('){
if(ptr < exp.length() && exp.charAt(ptr) == '-'){//左括号右边紧接-号，证明这是一个负数
String numBuffer = "-";
while(ptr < exp.length() && exp.charAt(ptr) != ')'){
numBuffer += exp.charAt(ptr++);
}
double value = Double.parseDouble(numBuffer);
numberStack.add(value);
ptr++;
}else{
operatorStack.add(cur);
}
}else if(cur == ')'){
char top = 0;
//操作符栈非空
if(!operatorStack.empty()) top = operatorStack.peek();
while(top != '('){
double num1 = numberStack.pop();
double num2 = numberStack.pop();
double res = 0;
char operator = operatorStack.pop();
switch (operator) {
case '+' -> res = num2 + num1;
case '-' -> res = num2 - num1;
case 'x' -> res = num2 * num1;
case '÷' -> {
if (num1 != 0) {
res = num2 / num1;
} else {
return new ExpRes("ERROR", "Divided by 0", 0);
}
}
}
numberStack.add(res);
if(!operatorStack.empty()) top = operatorStack.peek();
if(top == '(') top = operatorStack.pop();
}
}else if(cur == '+' || cur == '-' || cur == 'x' || cur == '÷'){
if(operatorStack.empty()) operatorStack.add(cur);
else {
char top = operatorStack.peek();
if(checkPriority(top, cur) == -1){
double num1 = numberStack.pop();
double num2 = numberStack.pop();
double res = 0;
char operator = operatorStack.pop();
switch (operator) {
case '+' -> res = num2 + num1;
case '-' -> res = num2 - num1;
case 'x' -> res = num2 * num1;
case '÷' -> {
if (num1 != 0) {
res = num2 / num1;
} else {
return new ExpRes("ERROR", "Divided by 0", 0);
}
}
}
operatorStack.add(cur);
numberStack.add(res);
}else{
operatorStack.add(cur);
}
}
}
}
if(!operatorStack.empty()){
while (!operatorStack.empty()){
double num1 = numberStack.pop();
double num2 = numberStack.pop();
double res = 0;
char operator = operatorStack.pop();
switch (operator) {
case '+' -> res = num2 + num1;
case '-' -> res = num2 - num1;
case 'x' -> res = num2 * num1;
case '÷' -> {
if (num1 != 0) {
res = num2 / num1;
} else {
return new ExpRes("ERROR", "Divided by 0", 0);
}
}
}
numberStack.add(res);
}
}
double exp_res = numberStack.pop();
return new ExpRes("OK", "", exp_res);
}
class ButtonMonitor implements ActionListener{
public void actionPerformed(ActionEvent e){
JButton clickBtn = (JButton)e.getSource();
for(int i = 0; i < btn_nums; i++){
if(clickBtn == btn_sets[i]){
if(done) result.setText("");
if(i == 2){//按下C(Clear)
result.setText("");
done = true;
}else if(i == 16){//按下负号
String exp = result.getText();
if(!exp.isEmpty() && checkLegality(exp.charAt(exp.length()-1), '_')){
addNegative();
done = false;
}
}else if(i == 19){//按下等号
System.out.println("Exp: " + result.getText());
getResult();
}else {
String exp = result.getText();
char pre_char = ' ';
if(!exp.isEmpty()){
pre_char = exp.charAt(exp.length()-1);
}
if(checkLegality(pre_char, btn_sets[i].getText().charAt(0))){
result.setText(exp + btn_sets[i].getText());
done = false;
}
}
}
}
}
}
class ExpRes{
String tag;
String msg;
double res;
public ExpRes(String tag, String msg, double res){
this.tag = tag;
this.msg = msg;
this.res = res;
}
}
}
4、计算器界面运行结果
5、计算器输入数据测试结果
6.程序流程图
四、实验结果
设计的包含登录界面的计算器运行成功。