简单加减乘除计算器

import java.awt.FlowLayout;import java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JButton;import javax.swing.JComboBox;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JOptionPane;import javax.swing.JPanel;import javax.swing.JTextField;import java.util.*;public class SuperCalculator extends JFrame implements ActionListenerprivate JLabel heading;private JPanel headerPanel;private JTextField number1 = null; private JComboBox op = null; private JTextField number2 = null; private JButton eq = null;private JButton clear = null;private JButton a1 = null;private JButton a2 = null;private JButton a3 = null;private JButton a4 = null;private JTextField result = null;public SuperCalculator()this.setLayout(new FlowLayout(FlowLayout.CENTER);this.add(heading = new JLabel(“ “);this.add(heading = new JLabel(“SUPER CALCULATOR“);this.add(heading = new JLabel(“ “);this.add(heading = new JLabel(“ “);this.add(heading = new JLabel(“ “);/this.setLayout(null)；/ this.add(heading = new JLabel(“ “);this.add(heading = new JLabel(“Numner1“);number1 = new JTextField(5);op = new JComboBox(new String“+“,“-“,“,“);number2 = new JTextField(5);eq = new JButton(“Exit“);eq.addActionListener(this);a1 = new JButton(“Add“);a1.addActionListener(this);a2 = new JButton(“Subtract“);a2.addActionListener(this);a3 = new JButton(“Multiple“);a3.addActionListener(this);a4 = new JButton(“Divide“);a4.addActionListener(this);clear = new JButton(“Clear“);clear.addActionListener(this);result = new JTextField(5);this.add(number1);this.add(heading = new JLabel(“Numner2“);this.add(number2);this.add(heading = new JLabel(“Result“);this.add(result);/this.result.disable();this.add(heading = new JLabel(“ “);this.add(heading = new JLabel(“ “);this.add(a1);this.add(a2);this.add(a3);this.add(a4);this.add(heading = new JLabel(“ “);this.add(clear); this.add(eq);this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);this.setSize(480, 280);this.setLocationRelativeTo(null);this.setTitle(“Super Calculator“);this.setResizable(false);this.setVisible(true);public static void main(String args) new SuperCalculator();Overridepublic void actionPerformed(ActionEvent arg0) if(arg0.getSource() = eq)System.exit(0); if(arg0.getSource() = a1)double n1 = 0.0;double n2 = 0.0;tryn1 = Double.parseDouble(number1.getText();catch(NumberFormatException nfe)JOptionPane.showMessageDialog(null, “number1 is not correct form“);tryn2 = Double.parseDouble(number2.getText();catch(NumberFormatException nfe)JOptionPane.showMessageDialog(null, “number2 is not correct form“);result.setText(String.valueOf(n1+n2);if(arg0.getSource() = a2)double n1 = 0.0;double n2 = 0.0;tryn1 = Double.parseDouble(number1.getText();catch(NumberFormatException nfe)JOptionPane.showMessageDialog(null, “number1 is not correct form“);tryn2 = Double.parseDouble(number2.getText();catch(NumberFormatException nfe)JOptionPane.showMessageDialog(null, “number2 is not correct form“);result.setText(String.valueOf(n1-n2);if(arg0.getSource() = a3)double n1 = 0.0;double n2 = 0.0;tryn1 = Double.parseDouble(number1.getText();catch(NumberFormatException nfe)JOptionPane.showMessageDialog(null, “number1 is not correct form“);tryn2 = Double.parseDouble(number2.getText();catch(NumberFormatException nfe)JOptionPane.showMessageDialog(null, “number2 is not correct form“);result.setText(String.valueOf(n1*n2);if(arg0.getSource() = a4)double n1 = 0.0;double n2 = 0.0;tryn1 = Double.parseDouble(number1.getText();catch(NumberFormatException nfe)JOptionPane.showMessageDialog(null, “number1 is not correct form“);tryn2 = Double.parseDouble(number2.getText();catch(NumberFormatException nfe)JOptionPane.showMessageDialog(null, “number2 is not correct form“);if(n2 != 0)result.setText(String.valueOf(n1/n2);elseJOptionPane.showMessageDialog(null, “you cannot divide a num