GUI03 简易计算器组合+内部类回顾复习

Posted 2021-02-18 xd-study

6、简易计算器、组合+内部类回顾复习

当前的代码（面向过程）

public class TestCalc {
    public static void main(String[] args) {
        new Calculator();
    }
}
//计算器类
class Calculator extends Frame{
    public Calculator() {
        //三个文本框
        TextField textField1 = new TextField(10);//字符数
        TextField textField2 = new TextField(10);//字符数
        TextField textField3 = new TextField(20);//字符数
        //一个按钮
        Button button = new Button("=");
        button.addActionListener(new MyCalculatorListener(textField1,textField2,textField3));
        //一个标签
        Label label = new Label("+");
        //布局
        setLayout(new FlowLayout());
        add(textField1);
        add(label);
        add(textField2);
        add(button);
        add(textField3);
        pack();
        setVisible(true);
    }
}
//监听器类
class MyCalculatorListener implements ActionListener{
    private TextField num1,num2,num3;
    public MyCalculatorListener(TextField num1,TextField num2,TextField num3) {
        this.num1 = num1;
        this.num2 = num2;
        this.num3 = num3;
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        //1.获取前两个数
        int n1 =Integer.parseInt(num1.getText());
        int n2 =Integer.parseInt(num2.getText());
        //2.将前面两个数相加放在第三个框
        int n3 = n1 + n2;
        num3.setText(Integer.toString(n3));
        //清除前二个数
        num1.setText("");
        num2.setText("");
    }
}

组合的方式优化（完全对象化），面向对象：

public class TestCalc {
    public static void main(String[] args) {
        new Calculator().loadFrame();
    }
}
//计算器类
class Calculator extends Frame{
    public  TextField num1,num2,num3;
    public void loadFrame() {
        //三个文本框
        num1 = new TextField(10);//字符数
        num2 = new TextField(10);//字符数
        num3 = new TextField(20);//字符数
        //一个按钮
        Button button = new Button("=");
        button.addActionListener(new MyCalculatorListener(this));
        //一个标签
        Label label = new Label("+");
        //布局
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(button);
        add(num3);
        pack();
        setVisible(true);
    }
}
//监听器类
class MyCalculatorListener implements ActionListener{
    Calculator calculator = null;
    public MyCalculatorListener(Calculator calculator) {
        this.calculator = calculator;
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        //1.获取前两个数
        int n1 =Integer.parseInt(calculator.num1.getText());
        int n2 =Integer.parseInt(calculator.num2.getText());
        //2.将前面两个数相加放在第三个框
        int n3 = n1 + n2;
        calculator.num3.setText(Integer.toString(n3));
        //清除前二个数
        calculator.num1.setText("");
        calculator.num2.setText("");
    }
}

内部类的优化：

public class TestCalc {
    public static void main(String[] args) {
        new Calculator().loadFrame();
    }
}
//计算器类
class Calculator extends Frame{
    public  TextField num1,num2,num3;
    public void loadFrame() {
        //三个文本框
        num1 = new TextField(10);//字符数
        num2 = new TextField(10);//字符数
        num3 = new TextField(20);//字符数
        //一个按钮
        Button button = new Button("=");
        button.addActionListener(new MyCalculatorListener());
        //一个标签
        Label label = new Label("+");
        //布局
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(button);
        add(num3);
        pack();
        setVisible(true);
    }
    //监听器类
    //内部类最大的好处是可以畅通无阻的访问外部类
    class MyCalculatorListener implements ActionListener{
        public void actionPerformed(ActionEvent e) {
            //1.获取前两个数
            int n1 =Integer.parseInt(num1.getText());
            int n2 =Integer.parseInt(num2.getText());
            //2.将前面两个数相加放在第三个框
            int n3 = n1 + n2;
            num3.setText(Integer.toString(n3));
            //清除前二个数
            num1.setText("");
            num2.setText("");
        }
    }
}