实现简易计算器 当按下“=”时能实现两个数的加减乘除

import javax.swing.*;import java.awt.*;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.util.ArrayList;import java.util.List;import static javax.swing.WindowConstants.EXIT_ON_CLOSE;public class Test01{public static void main(String[] args){List<String> cheng = new ArrayList();List<String> jia = new ArrayList();List<String> jian = new ArrayList();List<String> chu = new ArrayList();String str[] = {"%","CE","C","<-","7","8","9","*","4","5","6","-","1","2","3","+"};Font sansSerif = new Font("Times", Font.BOLD, 12);JFrame frame = new JFrame("计算器");JPanel jPanel1 = new JPanel();JPanel jPanel2 = new JPanel();JPanel jPanel3 = new JPanel();jPanel3.setLayout(new GridLayout(1,3,2,2));JButton jButton1 = new JButton("0");JButton jButton2 = new JButton(".");JButton jButton3 = new JButton("=");/*String text = jButton2.getText();System.out.println(text);*/JTextField jTextfield = new JTextField(5);jTextfield.setFont(sansSerif);jButton1.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {//显示的文字jTextfield.setText(jTextfield.getText()+jButton1.getText());/*jTextField.setBackground();*/}});jButton2.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {//显示的文字jTextfield.setText(jTextfield.getText()+jButton2.getText());/*jTextField.setBackground();*/}});jButton3.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {//显示的文字if(cheng.isEmpty() != true){String jTextfieldText = jTextfield.getText();cheng.add(jTextfieldText);int i = Integer.parseInt(cheng.get(0));int j = Integer.parseInt(cheng.get(1));int result1 = i*j;jTextfield.setText(jTextfield.getText()+jButton3.getText()+result1);}else if (jia.isEmpty() != true){String jTextfieldText = jTextfield.getText();jia.add(jTextfieldText);int i = Integer.parseInt(jia.get(0));int j = Integer.parseInt(jia.get(1));int result1 = i+j;jTextfield.setText(jTextfield.getText()+jButton3.getText()+result1);}else if (jian.isEmpty() != true){String jTextfieldText = jTextfield.getText();jian.add(jTextfieldText);int i = Integer.parseInt(jian.get(0));int j = Integer.parseInt(jian.get(1));int result1 = i-j;jTextfield.setText(jTextfield.getText()+jButton3.getText()+result1);}else if (chu.isEmpty() != true){String jTextfieldText = jTextfield.getText();chu.add(jTextfieldText);int i = Integer.parseInt(chu.get(0));int j = Integer.parseInt(chu.get(1));int result1 = i/j;jTextfield.setText(jTextfield.getText()+jButton3.getText()+result1);}/*jTextField.setBackground();*/}});jPanel3.add(jButton1);jPanel3.add(jButton2);jPanel3.add(jButton3);jPanel2.setLayout(new GridLayout(4,4,2,2));JButton btn[] = new JButton[str.length];for(int i = 0;i<str.length;i++){btn[i] = new JButton(str[i]);jPanel2.add(btn[i]);jPanel2.setFont(sansSerif);int finalI = i;if (i == 0){btn[0].addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {System.out.println("这里是除法");String content = jTextfield.getText();jTextfield.setText("");chu.add(content);}});}else if (i == 1) {btn[1].addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {System.out.println("这里是CE");int index = 0;String text1 = jTextfield.getText();for (int i = (text1.length() - 1); i >= 0; i--) {if (text1.charAt(i) == '+') {index = i;}}String result = text1.substring(0,index+1);jTextfield.setText(result);}});}else if (i == 2){btn[2].addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {jTextfield.setText("");jia.removeAll(jia);jian.removeAll(jian);cheng.removeAll(cheng);chu.removeAll(chu);}});}else if (i == 3){btn[3].addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {int length = jTextfield.getText().length();String result = jTextfield.getText().substring(0,length-1);jTextfield.setText(result);}});}else if (i == 7){btn[7].addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {System.out.println("这里是乘法");String content = jTextfield.getText();jTextfield.setText("");cheng.add(content);}});}else if (i == 11){btn[11].addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {System.out.println("这里是减法");String content = jTextfield.getText();jTextfield.setText("");jian.add(content);}});}else if (i == 15){btn[15].addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {System.out.println("这里是加法");String content = jTextfield.getText();jTextfield.setText("");jia.add(content);}});}else {btn[i].addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {jTextfield.setText(jTextfield.getText()+btn[finalI].getText());}});}}jPanel1.setSize(300,200);jPanel1.setLayout(new BorderLayout(2,2));jPanel1.add(jTextfield, "North");jPanel1.add(jPanel2, "Center");jPanel1.add(jPanel3, "South");frame.setContentPane(jPanel1);frame.setDefaultCloseOperation(EXIT_ON_CLOSE);frame.setSize(500, 500);frame.pack();frame.setVisible(true);}}