swing小计算器练习

这个计算器程序是对Swing的一个练习，逻辑比较简单

 

它只能进行单次运算(不能进行多项式运算)，考虑了除数不能为0的情况

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calculator extends JFrame 
implements ActionListener{	
	JTextField jtf = new JTextField();	
	JButton b1,b2,b3,b4,b5,b6,b7,b8,b9,b0;
    JButton badd,bsub,bmul,bdiv,bequal,bdot;
	int select = 0;
	JPanel jp1 = new JPanel();
	//分别代表0~9数字和加减乘除等于和点符号
	double temp = 0.0;
	double num = 0.0;
	public Calculator(){
		//生成两个区域，上面区域为一个文本域,下面为计算器的按钮
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		Container c = this.getContentPane();	
		jtf.setHorizontalAlignment(JTextField.RIGHT);
		c.add(jtf,BorderLayout.NORTH);
		c.add(jp1,BorderLayout.CENTER);
		
		jp1.setLayout(new GridLayout(4,4));
			
		b1 = new JButton("1");
		b1.addActionListener(this);
		jp1.add(b1);
		
		b2 = new JButton("2");
		b2.addActionListener(this);
		jp1.add(b2);
		
		b3 = new JButton("3");
		b3.addActionListener(this);
		jp1.add(b3);
		
		badd = new JButton("+");
		badd.addActionListener(this);
		jp1.add(badd);
		
		b4 = new JButton("4");
		b4.addActionListener(this);
		jp1.add(b4);
		
		b5 = new JButton("5");
		b5.addActionListener(this);
		jp1.add(b5);
		
		b6 = new JButton("6");
		b6.addActionListener(this);
		jp1.add(b6);
		
		bsub = new JButton("-");
		bsub.addActionListener(this);
		jp1.add(bsub);
		
		b7 = new JButton("7");
		b7.addActionListener(this);
		jp1.add(b7);
		
		b8 = new JButton("8");
		b8.addActionListener(this);
		jp1.add(b8);
		
		b9 = new JButton("9");
		b9.addActionListener(this);
		jp1.add(b9);
		
		bmul = new JButton("*");
		bmul.addActionListener(this);
		jp1.add(bmul);
		
		b0 = new JButton("0");
		b0.addActionListener(this);
		jp1.add(b0);
		
		bdot = new JButton(".");
		bdot.addActionListener(this);
		jp1.add(bdot);
		
		bequal = new JButton("=");
		bequal.addActionListener(this);
		jp1.add(bequal);
		
		bdiv = new JButton("//");
		bdiv.addActionListener(this);
		jp1.add(bdiv);	
	}
	public void actionPerformed(ActionEvent e){
		//jtf.setText(jtf.getText()+e.getActionCommand());
		if(e.getSource() == b1){
			jtf.setText(jtf.getText()+e.getActionCommand());
		}
		if(e.getSource() == b2){
			jtf.setText(jtf.getText()+e.getActionCommand());
		}
		if(e.getSource() == b3){
			jtf.setText(jtf.getText()+e.getActionCommand());
		}
		if(e.getSource() == b4){
			jtf.setText(jtf.getText()+e.getActionCommand());
		}
		if(e.getSource() == b5){
			jtf.setText(jtf.getText()+e.getActionCommand());
		}
		if(e.getSource() == b6){
			jtf.setText(jtf.getText()+e.getActionCommand());
		}
		if(e.getSource() == b7){
			jtf.setText(jtf.getText()+e.getActionCommand());
		}
		if(e.getSource() == b8){
			jtf.setText(jtf.getText()+e.getActionCommand());
		}
		if(e.getSource() == b9){
			jtf.setText(jtf.getText()+e.getActionCommand());
		}
		if(e.getSource() == b0){
			jtf.setText(jtf.getText()+e.getActionCommand());
		}
		if(e.getSource() == badd){
			temp = Double.parseDouble(jtf.getText());
			jtf.setText("");
			select = 1;
		}
		if(e.getSource() == bsub){
			temp = Double.parseDouble(jtf.getText());
			jtf.setText("");
			select = 2;
		}
		if(e.getSource() == bmul){
			temp = Double.parseDouble(jtf.getText());
			jtf.setText("");
			select = 3;
		}
		if(e.getSource() == bdiv){
			temp = Double.parseDouble(jtf.getText());
			jtf.setText("");
			select = 4;
		}
		if(e.getSource() == bequal){
			if(select == 1){
				num = Double.parseDouble(jtf.getText());
				jtf.setText((num = temp+num)+"");
			}
			else if(select == 2){
				num = Double.parseDouble(jtf.getText());
				jtf.setText((num = temp-num)+"");
			}
			else if(select == 3){
				num = Double.parseDouble(jtf.getText());
				jtf.setText((num = temp*num)+"");
			}
			else if(select == 4){
				num = Double.parseDouble(jtf.getText());
				if(num == 0){
					JOptionPane.showMessageDialog(jp1, "除数不能为0");
				}
				jtf.setText((num = temp/num)+"");
			}
		}
	}
	public static void main(String[] args) {
		Calculator mainFrame = new Calculator();
		mainFrame.setSize(400,400);
		mainFrame.setTitle("calculator by jk");
		mainFrame.setVisible(true);
	}
}