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
}
}
