ActionListener未实现

Question

我正在学习JRadoButton，并在这个特定的程序中制作了三个JRadoButton。JRadoButton是pizzaButton、burgerButton和hotdogButton。当用户选择其中之一时，我想打印特定的行。我覆盖了ActionPer的方法，甚至为每个无线电按钮实现了ActionListener。但是每次尝试后，程序似乎都忽略了ActionPer的方法。'

public class Main {

    public static void main(String[] args) {

        new MyFrame();
    }
}

`` `

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

public class MyFrame extends JFrame implements ActionListener {

    JRadioButton pizzaButton;
    JRadioButton burgerButton;
    JRadioButton hotdogButton;

    MyFrame() {

        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        this.setLayout(new FlowLayout());

        JRadioButton pizzaButton = new JRadioButton("pizza");
        JRadioButton burgerButton = new JRadioButton("burger");
        JRadioButton hotdogButton = new JRadioButton("hot dog");

        ButtonGroup group = new ButtonGroup();
        group.add(pizzaButton);
        group.add(burgerButton);
        group.add(hotdogButton);

        pizzaButton.addActionListener(this);
        burgerButton.addActionListener(this);
        hotdogButton.addActionListener(this);

        this.setVisible(true);
        this.add(pizzaButton);
        this.add(burgerButton);
        this.add(hotdogButton);
        this.pack();
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource()==pizzaButton) {
            System.out.println("You ordered a pizza");
        } else if (e.getSource()==burgerButton) {
            System.out.println("You ordered a burger");
        } else if (e.getSource()==hotdogButton) {
            System.out.println("You ordered a hot dog");
        }
    }
}

``

我尝试检查可能出错的地方，并仔细检查是否将ActionListener添加到了JRadioButtons中。

Answer 1

您覆盖了您的引用，执行的操作比较了两个不同的对象。

改变

    JRadioButton pizzaButton = new JRadioButton("pizza");
    JRadioButton burgerButton = new JRadioButton("burger");
    JRadioButton hotdogButton = new JRadioButton("hot dog");

自

    pizzaButton = new JRadioButton("pizza");
    burgerButton = new JRadioButton("burger");
    hotdogButton = new JRadioButton("hot dog");

Answer 2

在actionPerformed（）中，您将按钮作为类属性引用，而在构造函数中，您使用本地变量，这意味着不同的对象。尝试更改：

        JRadioButton pizzaButton = new JRadioButton("pizza");
        JRadioButton burgerButton = new JRadioButton("burger");
        JRadioButton hotdogButton = new JRadioButton("hot dog");

到…里面

        this.pizzaButton = new JRadioButton("pizza");
        this.burgerButton = new JRadioButton("burger");
        this.hotdogButton = new JRadioButton("hot dog");