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);}}