java swing 简易计算器

源码如下：

package test;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

class myFrame extends JFrame {
   public myFrame() {
       setTitle("计算器");
       add(new myPanel());
       pack();
   }
}

class myPanel extends JPanel {
   //显示计算器按钮的值和计算后的值
   JTextField display;
   JPanel panel1;//面板1
   JPanel panel2;//面板2
   String nowButton;//当前按下的

   public myPanel() {

       setLayout(new BorderLayout());

       //把文本框加在上面north里
       display = new JTextField("");
       display.setEnabled(true);
       add(display, BorderLayout.NORTH);

       //监听操作按钮
       ActionListener command = new commandAction();

       //panel1是中间16个按钮的布局，放到布局管理器的center里
       panel1 = new JPanel();
       panel1.setLayout(new GridLayout(4, 4));

       addButton1("7", command);
       addButton1("8", command);
       addButton1("9", command);
       addButton1("+", command);
       addButton1("4", command);
       addButton1("5", command);
       addButton1("6", command);
       addButton1("-", command);
       addButton1("1", command);
       addButton1("2", command);
       addButton1("3", command);
       addButton1("*", command);
       addButton1(".", command);
       addButton1("0", command);
       addButton1("=", command);
       addButton1("/", command);

       add(panel1, BorderLayout.CENTER);


       //panel2是下面的backspace和c的2个的布局，放到布局管理器的south里
       panel2 = new JPanel();
       panel2.setLayout(new GridLayout(1, 2));

       addButton2("BackSace", command);
       addButton2("C", command);

       add(panel2, BorderLayout.SOUTH);

   }

   //注册事件监听器方法（panel1的）
   public void addButton1(String label ,ActionListener listener) {
       JButton button = new JButton(label);
       button.addActionListener(listener);
       panel1.add(button);
   }

   //注册监听器方法（panel2的）
   private void addButton2(String label, ActionListener listener) {
       // TODO 自动生成的方法存根
       JButton button = new JButton(label);
       button.addActionListener(listener);
       panel2.add(button);
   }

   //单击按钮执行命令的监听器
   class commandAction implements ActionListener {
       @Override
       public void actionPerformed(ActionEvent event) {
           // TODO 自动生成的方法存根
           nowButton = event.getActionCommand();

           if (nowButton != "BackSace" && nowButton != "=") {
               //如果是回退和=就不打印这个了
               display.setText(display.getText() + nowButton);
           }

           if (nowButton.equals("=")) {
               //如果是等于号，就计算结果
               display.setText(jisuan1(display.getText()));
           }

           if (nowButton.equals("BackSace")) {
               //回退一个字符
               StringBuffer sb = new StringBuffer(display.getText());
               display.setText(sb.substring(0, sb.length()-1));
           }
           if (nowButton.equals("C")) {
               //清空
               display.setText("");
           }
       }
   }

   //用来计算的方法
   public String jisuan1(String string) {
       StringBuffer sb = new StringBuffer(string);
       int commandCount = 0;//符号数量

       int j = 0;//计数器
       //计算有多少个运算符，就有n+1个数字
       for (j = 0; j < sb.length(); j++) {
           if (sb.charAt(j) <= '9' && sb.charAt(j) >= '0' || sb.charAt(j) == '.') {
               continue;
           }else {
               commandCount++;
           }
       }

       //初始化符号数组
       char[] command = new char[commandCount];
       //初始化数字数组（用字符串表示）
       String[] num = new String[commandCount+1];
       for (j = 0; j < num.length; j++) {
           num[j] = "";
       }

       //遍历一遍，吧每个数字存进数字数组，每个符号存进符号数组
       int k = 0;
       for (j = 0; j < sb.length(); j++) {
           if (sb.charAt(j) <= '9' && sb.charAt(j) >= '0' || sb.charAt(j) == '.') {
               num[k] += sb.charAt(j);
               continue;
           }else {
               command[k] = sb.charAt(j);
               k++;
           }
       }

       //计算结果
       double result = 0;
       for (int i = 0; i < commandCount; i++) {

           //取前两个数，和第一个操作符，运算
           double num1 = Double.parseDouble(num[i]);
           double num2 = Double.parseDouble(num[i+1]);
           char cc = command[i];

           //计算
           switch (cc) {
           case '+':
               result = num1 + num2;
               break;
           case '-':
               result = num1 - num2;
               break;
           case '*':
               result = num1 * num2;
               break;
           case '/':
               result = num1 / num2;
               break;
           default:
               break;
           }
           num[i+1] = String.valueOf(result);
       }

       return String.valueOf(result);
   }
}

public class JiSuanQi {
   public static void main(String[] args) {
       myFrame frame = new myFrame();
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//关闭窗口
       frame.setVisible(true);
   }
}

java swing 简易计算器

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