总结：虽然，没有人会帮你到底，凭什么要对你怜香惜玉

注意实现哪一个运算就把相关代码放在else if这个判断语句里面

package com.rue;

import java.awt.BorderLayout;

import java.awt.FlowLayout;

import java.awt.Font;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.*;

//实现计算器的功能，我他妈的真是不懂变通。

class Ji extends JFrame implements ActionListener {

private static final String CE = null;

// 定义按钮

StringBuffer str = new StringBuffer();

JButton jb_0, jb_1, jb_2, jb_3, jb_4, jb_5, jb_6, jb_7, jb_8, jb_9, jb_jia,

jb_jian, jb_cheng, jb_chu, jb_dian, jb_deng, jb_delete;

JLabel jf;

double num1 = 0;

double num2 = 0;

char c = '\0';

double m;

boolean ready = true;

public Ji() {

JPanel jp = new JPanel(new GridLayout(5, 4));// 把所有的按钮组件和文本框放在这个panel里面

jf = new JLabel("0.0");

jf.setFont(new Font("", 1, 18));

jf.setHorizontalAlignment(JLabel.RIGHT);

jb_delete = new JButton("CE");// 设一个删除的按钮

jb_0 = new JButton("0");

JButton jb_genghao = new JButton("√");

jb_1 = new JButton("1");

jb_genghao.addActionListener(this);

jb_2 = new JButton("2");

jb_3 = new JButton("3");

jb_4 = new JButton("4");

jb_5 = new JButton("5");

jb_6 = new JButton("6");

jb_7 = new JButton("7");

jb_8 = new JButton("8");

jb_9 = new JButton("9");

jb_jia = new JButton("+");

jb_jian = new JButton("-");

jb_cheng = new JButton("*");

jb_chu = new JButton("/");

jb_dian = new JButton(".");

jb_deng = new JButton("=");

//

jb_delete.addActionListener(this);

jb_0.addActionListener(this);

jb_1.addActionListener(this);

jb_2.addActionListener(this);

jb_3.addActionListener(this);

jb_4.addActionListener(this);

jb_5.addActionListener(this);

jb_6.addActionListener(this);

jb_7.addActionListener(this);

jb_8.addActionListener(this);

jb_9.addActionListener(this);

jb_jia.addActionListener(this);

jb_jian.addActionListener(this);

jb_cheng.addActionListener(this);

jb_chu.addActionListener(this);

jb_dian.addActionListener(this);

jb_deng.addActionListener(this);

JButton jb_Back = new JButton("Back");

jb_Back.addActionListener(this);

jp.add(jb_1);

jp.add(jb_2);

jp.add(jb_3);

jp.add(jb_4);

jp.add(jb_5);

jp.add(jb_6);

jp.add(jb_7);

jp.add(jb_8);

// this.add(jp);

jp.add(jb_9);

jp.add(jb_jia);

jp.add(jb_jian);

jp.add(jb_cheng);

jp.add(jb_chu);

jp.add(jb_dian);

jp.add(jb_deng);

jp.add(jb_0);

jp.add(jb_Back);

jp.add(jb_delete);

jp.add(jb_genghao);

this.add(jf, BorderLayout.NORTH);

this.add(jp);

// this.setLayout();

this.setVisible(true);

this.setBounds(100, 20, 230, 300);

this.setDefaultCloseOperation(3);

}

public double count() {

switch (c) {

case '+':

m = num1 + num2;

break;

case '-':

m = num1 - num2;

break;

case '*':

m = num1 * num2;

break;

case '/':

m = num1 / num2;

break;

case '√':

m = Math.sqrt(num1);

break;

case 'E':

m = '\0';

}

return m;

}

public void actionPerformed(ActionEvent e) {

String str = e.getActionCommand();

if (str.equals("0") || str.equals(".") || str.equals("1")

|| str.equals("2") || str.equals("3") || str.equals("4")

|| str.equals("5") || str.equals("6") || str.equals("7")

|| str.equals("8") || str.equals("9") || str.equals("1")) {

if (ready) {

jf.setText(str);

ready = false;

} else {

jf.setText(jf.getText() + str);

ready = false;

}

} else if (str.equals("+")) {

num1 = Double.parseDouble(jf.getText());

// count();

// 其实可以感觉到操作符有点不正常的。就是操作符设置的问题有点大

// if(num1=){}

c = '+';

ready = true;

} else if (str.equals("√")) {

num1 = Double.parseDouble(jf.getText());

c = '√';

ready = true;

} else if (str.equals("CE")) {

num1 = Double.parseDouble(jf.getText());

// c='c';//这里可以判断按的是哪一个按钮吗？

jf.setText("0.0");// 记住这里是要清空，但并不是把lable也全部删除看不见。Label的作用。

ready = true;// 当这里为false时，它会与0.0连接一起显示出来，此时设置我ture。它正常了。是不是继续执行下一步的意思呢？

} else if (str.equals("-")) {

num1 = Double.parseDouble(jf.getText());

c = '-';

ready = true;

} else if (str.equals("*")) {

num1 = Double.parseDouble(jf.getText());

c = '*';

ready = true;

} else if (str.equals("/")) {

num1 = Double.parseDouble(jf.getText());

c = '/';

ready = true;

} else if (str.equals("=")) {

num2 = Double.parseDouble(jf.getText());

jf.setText(count() + "");

ready = false;

}

}

}

public class Test {

public static void main(String[] args) {

new Ji();

}

}