java用Swing编写简单计算器

先写个用来处理计算的类Calculate

import java.util.*;
public class Calculate {
	public  static Stack num=new Stack();
	public  static Stack operator =new Stack();
	public  static void work(){
		String s2=num.pop();
		String s1=num.pop();
		float num2=Float.parseFloat(s2);
		float num1=Float.parseFloat(s1);
	        String op=operator.pop();
	        float num3;
		switch(op){
	              case "+":  num3=num1+num2;num.push(num3+"");break;
	              case "-":  num3=num1-num2;num.push(num3+"");break;
	              case "*":  num3=num1*num2;num.push(num3+"");break;
	              case "/":  num3=num1/num2;num.push(num3+"");break;
		}
	}
	public static String count(String s) {
		 int i = 0;
		 while ( i < s.length ( ) ) {
			 switch ( s.charAt ( i ) )
			 {
			    case '+':
			    case '-':  while(!operator.empty()) {
					    work();
				       }
				       operator.push(s.charAt(i)+"");
				       i++;
				       break;
			    case '*':
			    case '/':   while(!operator.empty()&&(operator.peek().equals("*")||operator.peek().equals("/"))) {	
			                     work();
					     System.out.println("Ok");
				        }
				        operator.push(s.charAt(i)+"");
				        i++;
				        break;
			     default :  String number="";
				        for(;i='0'&&s.charAt(i)<='9'||s.charAt(i)=='.');i++) {
				        	  number=number+s.charAt(i);
				        }
				        num.push(number);
			}
		 }
		 while(!operator.empty()) {
			work();
		 }
		 return num.peek();
	}
}

编写计算器界面和添加AWT事件及处理

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calculator extends JFrame implements ActionListener{
	static Calculator frm=new Calculator();
	static JPanel pan1=new JPanel();
	static JPanel pan2=new JPanel();
	static JTextField tf=new JTextField("0");
	static JButton[] b=new JButton[10];
	static JButton bp,ba,bs,bm,bd,be,bc,br;
	String expression=new String();
	public static void main(String[] args) {
		for(int i=0;i<=9;i++)
			b[i]=new JButton(""+i);
		bp=new JButton(".");ba=new JButton("+");
		bs=new JButton("-");bm=new JButton("*");
		bd=new JButton("/");be=new JButton("=");
		bc=new JButton("c");br=new JButton("<--");
		frm.setTitle("计算器");
		frm.setLayout(null);
		frm.setSize(300,280);
		frm.setResizable(false);
		GridLayout grid1=new GridLayout(4,4);
		GridLayout grid2=new GridLayout(1,2);
		pan1.setLayout(grid1);
		pan2.setLayout(grid2);
		tf.setBounds(45,15,200,25);
		pan1.setBounds(45,50,200,120);
		pan2.setBounds(45,170,200,30);
		tf.setBackground(Color.CYAN);
		tf.setHorizontalAlignment(JTextField.RIGHT);
		pan1.add(b[7]);pan1.add(b[8]);pan1.add(b[9]);pan1.add(bd);
		pan1.add(b[4]);pan1.add(b[5]);pan1.add(b[6]);pan1.add(bm);
		pan1.add(b[1]);pan1.add(b[2]);pan1.add(b[3]);pan1.add(bs);
		pan1.add(b[0]);pan1.add(bp);pan1.add(be);pan1.add(ba);
		pan2.add(bc);pan2.add(br);
		frm.add(tf);
		frm.add(pan1);
		frm.add(pan2);
		for(int i=0;i<=9;i++)
			 b[i].addActionListener(frm);
		bd.addActionListener(frm);bm.addActionListener(frm);
		bs.addActionListener(frm);ba.addActionListener(frm);
		bc.addActionListener(frm);br.addActionListener(frm);
		bp.addActionListener(frm);be.addActionListener(frm);
		frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frm.setVisible(true);
	}
	public void actionPerformed(ActionEvent e) {
		if(e.getActionCommand().equals("=")){
			expression=Calculate.count(expression);
			tf.setText(expression);
		}
		else if(e.getActionCommand().equals("c")){
			expression="";
			tf.setText("0");
		}
		else if(e.getActionCommand().equals("<--")){
			expression=expression.substring(0,expression.length()-1);
			tf.setText(expression);
		}
		else{
		    expression+=e.getActionCommand();
		    tf.setText(expression);
		}
	}
}