简易计算器
oop原则:组合大于继承
基础写法
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
//简易计算器
public class TextCalc {
public static void main(String[] args) {
new Calculator();
}
}
//计算器类
class Calculator extends Frame{
public Calculator() {
//3个文本框TextField
TextField num1 = new TextField(10);
TextField num2 = new TextField(10);
TextField num3 = new TextField(20);
//1个按钮Button
Button button = new Button("=");
button.addActionListener(new MyCalculator(num1,num2,num3) );
//1个标签Label
Label label = new Label("+");
//布局
setLayout(new FlowLayout());
add(num1);
add(label);
add(num2);
add(button);
add(num3);
pack();
setVisible(true);
}
}
//计算器监听类
class MyCalculator implements ActionListener {
private TextField num1,num2,num3;
public MyCalculator(TextField num1,TextField num2,TextField num3) {
this.num1=num1;
this.num2=num2;
this.num3=num3;
}
@Override
public void actionPerformed(ActionEvent e) {
//获得加数和被加数
int n1 = Integer.parseInt(num1.getText());
int n2 = Integer.parseInt(num2.getText());
//进行加法运算,结果放到第三个框
num3.setText(""+(n1+n2));
//清除前两个框
num1.setText("");
num2.setText("");
}
}
完全面向对象
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
//简易计算器
public class TextCalc {
public static void main(String[] args) {
new Calculator().loadFrame();
}
}
//计算器类
class Calculator extends Frame{
//属性
TextField num1,num2,num3;
//方法
public void loadFrame(){
//3个文本框TextField
num1 = new TextField(10);
num2 = new TextField(10);
num3 = new TextField(20);
Button button = new Button("=");
Label label = new Label("+");
button.addActionListener(new MyCalculator(this) );
//布局
setLayout(new FlowLayout());
add(num1);
add(label);
add(num2);
add(button);
add(num3);
pack();
setVisible(true);
}
}
//计算器监听类
class MyCalculator implements ActionListener {
Calculator calculator = null;
public MyCalculator(Calculator calculator) {
this.calculator=calculator;
}
@Override
public void actionPerformed(ActionEvent e) {
//1获得加数和被加数
//2进行加法运算,结果放到第三个框
//3清除前两个框
int n1 = Integer.parseInt(calculator.num1.getText());
int n2 = Integer.parseInt(calculator.num2.getText());
calculator.num3.setText(""+(n1+n2));
calculator.num1.setText("");
calculator.num2.setText("");
}
}
内部类
- 更好的包装
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
//简易计算器
public class TextCalc {
public static void main(String[] args) {
new Calculator().loadFrame();
}
}
//计算器类
class Calculator extends Frame{
//属性
TextField num1,num2,num3;
//方法
public void loadFrame(){
//3个文本框TextField
num1 = new TextField(10);
num2 = new TextField(10);
num3 = new TextField(20);
Button button = new Button("=");
Label label = new Label("+");
button.addActionListener(new MyCalculator() );
//布局
setLayout(new FlowLayout());
add(num1);
add(label);
add(num2);
add(button);
add(num3);
pack();
setVisible(true);
}
//内部类最大的好处,就是可以畅通无阻的访问外部类的属性和方法,降低了编码成本
private class MyCalculator implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
//1获得加数和被加数
//2进行加法运算,结果放到第三个框
//3清除前两个框
int n1 = Integer.parseInt(num1.getText());
int n2 = Integer.parseInt(num2.getText());
num3.setText(""+(n1+n2));
num1.setText("");
num2.setText("");
}
}
}