Java界面计算器的实现

实现一个计算器，运行界面如下：

运行界面
在eclipse中运行通过
主要运用了Java的图形界面显示，流式布局方式，使用监听器,实现简单的加减乘除计算，结果显示在result文本框中

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

public class Calculator extends JFrame { 

public Calculator(){ 

setLayout(new FlowLayout(FlowLayout.LEFT,10,20)); //建立流式布局 
add(new JLabel("Number 1")); 
JTextField tf1 = new JTextField(3); //文本框JTextFiled
 add(tf1); 

add(new JLabel("Number 2")); 
JTextField tf2 = new JTextField(3); //文本框JTextFiled 
add(tf2);

 add(new JLabel("result")); 
JTextField tf3 = new JTextField(5); //文本框JTextFiled 
add(tf3);

 JButton btnAdd = new JButton("Add"); //Add按钮引用对象名为btnAdd 
add( btnAdd);

 btnAdd.addActionListener(new ActionListener() { //加一个监听器 

public void actionPerformed(ActionEvent e) { //实现功能的方法

 double result = Double.parseDouble(tf1.getText()) + Double.parseDouble(tf2.getText()); 
 tf3.setText(result+"");  //将result的结果转换为string形式显示在tf3对应的文本框中
 }
 }); 

JButton btnSubtract = new JButton("Subtract"); 
add(btnSubtract);

 btnSubtract.addActionListener(new ActionListener(){ 

public void actionPerformed(ActionEvent e) { 

double result = Double.parseDouble(tf1.getText()) - Double.parseDouble(tf2.getText()); 

tf3.setText(result+"");
 }
 }); 

JButton btnMultiply = new JButton("Multiply"); 
add(btnMultiply); 

btnMultiply.addActionListener(new ActionListener(){ 

public void actionPerformed(ActionEvent e) {

 double result = Double.parseDouble(tf1.getText()) * Double.parseDouble(tf2.getText());

 tf3.setText(result+""); 
} 
});

 JButton btnDivide = new JButton("Divide"); 
add(btnDivide); 

btnDivide.addActionListener(new ActionListener(){ 

public void actionPerformed(ActionEvent e) { 

double result = Double.parseDouble(tf1.getText()) / Double.parseDouble(tf2.getText());

 tf3.setText(result+"");
 }
 });
}


 public static void main(String[] args) { 

Calculator frame = new Calculator(); 

frame.setTitle("Exercise16_4"); //设置标题

 frame.setSize(360,200); //设置框的初始大小 

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); /*设置关闭按钮*/

 frame.setVisible(true); //显示界面
 }
}