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();	}}