如何使用非抽象类实现 ActionListener?爪哇 [英] How can I implement ActionListener with a non abstract class? Java

问题描述

我最近才开始学习如何使用 Swing，并且一直在学习我在网上找到的教程.我基本上是按照教程逐字逐句"进行的，但出现错误:

I've just recently started learning how to use swing, and have been following a tutorial I found online. I've basically followed the tutorial "word for word" but I get the error:

ScoreBoard 不是抽象的，也不会覆盖抽象方法ActionListener 中的 actionPerformed(ActionEvent)

ScoreBoard is not abstract and does not override abstract method actionPerformed(ActionEvent) in ActionListener

所以我的问题是，如果类不是抽象类，我如何将 ActionListener 实现到我的类 (ScoreBoard) 中?

So my question is, how can I implement ActionListener into my class (ScoreBoard) if the class is not abstract?

这是完整的代码:(因为我不知道问题出在哪里)

Here is the entire code: (Because I have no idea where the problem could be)

package scoreboard;

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

public class ScoreBoard implements ActionListener{

//Class Variables
int redScore = 0;
int blueScore = 0;

//Class Objects
JPanel titlePanel, scorePanel, buttonPanel;
JLabel redLabel, blueLabel, redLabelT, blueLabelT;
JButton redButton, blueButton, resetButton;


public static void main(String[] args) {

    SwingUtilities.invokeLater(new Runnable(){
        public void run(){
            createFrame();
        }
    });

}//End Method

public static void createFrame(){

    JFrame frame = new JFrame("ScoreBoard");
    JFrame.setDefaultLookAndFeelDecorated(true);

    ScoreBoard panel = new ScoreBoard();
    frame.setContentPane(panel.contentPane());

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setResizable(false);
    frame.setSize(250, 190);
    frame.setVisible(true);

}//End Method

public JPanel contentPane(){

    JPanel basePanel = new JPanel();
    basePanel.setLayout(null);
    basePanel.setBackground(Color.black);

    //Title
    titlePanel = new JPanel();
    titlePanel.setLayout(null);
    titlePanel.setOpaque(false);
    titlePanel.setLocation(10, 0);
    titlePanel.setSize(250, 30);
    basePanel.add(titlePanel);

    redLabelT = new JLabel("Red Team");
    redLabelT.setLocation(0, 0);
    redLabelT.setSize(100, 30);
    redLabelT.setForeground(Color.red);
    redLabelT.setHorizontalAlignment(0);
    titlePanel.add(redLabelT);

    blueLabelT = new JLabel("Blue Team");
    blueLabelT.setLocation(120, 0);
    blueLabelT.setSize(100, 30);
    blueLabelT.setForeground(Color.blue);
    blueLabelT.setHorizontalAlignment(0);
    titlePanel.add(blueLabelT);

    //Score
    scorePanel = new JPanel();
    scorePanel.setLayout(null);
    scorePanel.setOpaque(false);
    scorePanel.setLocation(10, 40);
    scorePanel.setSize(250, 30);
    basePanel.add(scorePanel);

    redLabel = new JLabel("" + redScore);
    redLabel.setLocation(0, 0);
    redLabel.setSize(100, 30);
    redLabel.setForeground(Color.white);
    redLabel.setHorizontalAlignment(0);
    scorePanel.add(redLabel);

    blueLabel = new JLabel("" + blueScore);
    blueLabel.setLocation(120, 0);
    blueLabel.setSize(100, 30);
    blueLabel.setForeground(Color.white);
    blueLabel.setHorizontalAlignment(0);
    scorePanel.add(blueLabel);

    //Buttons
    buttonPanel = new JPanel();
    buttonPanel.setLayout(null);
    buttonPanel.setOpaque(false);
    buttonPanel.setLocation(10, 80);
    buttonPanel.setSize(250, 70);
    basePanel.add(buttonPanel);

    redButton = new JButton("Red Score");
    redButton.setLocation(0, 0);
    redButton.setSize(100, 30);
    redButton.addActionListener(this);
    buttonPanel.add(redButton);

    blueButton = new JButton("Blue Score");
    blueButton.setLocation(120, 0);
    blueButton.setSize(100, 30);
    blueButton.addActionListener(this);
    buttonPanel.add(blueButton);

    resetButton = new JButton("Reset");
    resetButton.setLocation(0, 40);
    resetButton.setSize(220, 30);
    resetButton.addActionListener(this);
    buttonPanel.add(resetButton);

    return basePanel;

   }//End Method

public void actions(ActionEvent e){

    if(e.getSource() == redButton){

        redScore ++;
        redLabel.setText("" + redScore);

    }else if(e.getSource() == blueButton){

        blueScore++;
        blueLabel.setText("" + blueScore);

    }else if(e.getSource() == resetButton){

        redScore = 0;
        blueScore = 0;
        redLabel.setText("" + redScore);
        blueLabel.setText("" + blueScore);

    }

}//End Method

}//End Class

另外，如果你能解释抽象类是什么，那也会有帮助，但实际上我现在只需要知道如何让 JButtons 工作......

Also if you can explain what an Abstract class is, that'd help too, but really I just need to know how to get JButtons working for now...

谢谢！

推荐答案

将此方法放入您的 ScoreBoard 类-

Put this method into your ScoreBoard class-

@Override
public void actionPerformed(ActionEvent ae) {
     // do something
}

如果不想让ScoreBoard类实现ActionListener，也可以这样添加监听器-

You can also add listener in this way, if you don't want ScoreBoard class to implement ActionListener-

redButton.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent ae) {
         // do something
    }
};

如果要共享侦听器，请创建其实例并将其添加到所有按钮中.

If you want to share the listener, create its instance and add it to all the buttons.

要了解抽象类，请阅读此 http://docs.oracle.com/javase/tutorial/java/IandI/abstract.html

To learn about abstract classes, read this http://docs.oracle.com/javase/tutorial/java/IandI/abstract.html

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