Java实训项目之编写计算器（练习书中例题）

public class Example8_9 {
    public static void main(String [] args){
     NumberView win = new NumberView();
     win.setBounds(100,100,600,360);
     win.setTitle("计算器");
    }
}

import javax.swing.*;
import java.awt.*;

public class NumberView extends JFrame {
    public JTextField inputNunmberOne ,inputNumberTwo;
    public JComboBox  choiceFuhao;
    public JTextArea textShow;
    public JButton button;
    public OperatorListener operator;      //监听ItemEvent事件的监视器
    public  ComputerListener computer;     //监听ActionEvent事件的监视器
    public NumberView(){
        init();
        setVisible(true);
        SetDefaultCloseOpertion(JFrame.EXIT_ON_CLOSE);
    }

    private void SetDefaultCloseOpertion(int exitOnClose) {
    }

    private void init() {
        setLayout(new FlowLayout());
        Font font = new Font("宋体",Font.BOLD,22);
        inputNumberTwo = new JTextField(5);
        inputNunmberOne = new JTextField(5);
        inputNunmberOne.setFont(font);
        inputNumberTwo.setFont(font);
        choiceFuhao = new JComboBox<>();
        choiceFuhao.setFont(font);
        button = new JButton("计算");
        button.setFont(font);
        choiceFuhao.addItem("选择运算符号：");
        String [] a = {"+","-","*","/"};
        for (int i=0;i

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

public class OperatorListener implements ItemListener, ActionListener {
    NumberView view;
    public void setView(NumberView view){
        this.view=view;
    }
    public void itemStateChanged(ItemEvent e){
        String fuhao = view.choiceFuhao.getSelectedItem().toString();
        view.computer.setFuhao(fuhao);
    }
    public void actionPerformed(ActionEvent e){
        String fuhao = view.choiceFuhao.getSelectedItem().toString();
        view.computer.setFuhao(fuhao);
    }
}

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class ComputerListener implements ActionListener {
    NumberView view;
    String fuhao;
    public void setView(NumberView view){
        this.view=view;
    }
    public  void setFuhao(String s){
        fuhao=s;
    }
    public void actionPerformed(ActionEvent e){
        try {
            double number1=Double.parseDouble(view.inputNunmberOne.getText());
            double number2=Double.parseDouble(view.inputNumberTwo.getText());
            double result = 0;
            boolean isShow = true;
            if (fuhao.equals("+")){
                result=number1+number2;
            }
           else if (fuhao.equals("-")){
                result=number1-number2;
            }
           else if (fuhao.equals("*")){
                result=number1*number2;
            }
           else if (fuhao.equals("/")){
                result=number1/number2;
            }
           else {
               isShow=false;
            }
           if (isShow){
               view.textShow.append(number1+" "+fuhao+" "+number2+" = "+result+"n");
           }
        }
        catch (Exception exp){
            view.textShow.append("n请输入数字字符n");
        }
    }
}