Java Timer 类操作执行更新两秒

Question

我目前正在实施一个简单的篮球记分牌程序。 对于记分牌，我使用的是java内置的javax.swing.Timer类。 我试图让显示屏在每次计时器调用动作时减少一秒。 截至目前，每次调用 actionPerforming 时，它都会减少 2。 任何提示或帮助将不胜感激。 谢谢！

另外，如果我问得不正确或太模糊，我很抱歉。 我是新来的。 如果您需要澄清或需要我修复某些问题，请告诉我。 我已经包含了片段，然后在最后包含了完整的代码。

这是我的代码中实例化计时器的部分：

Timer clock;
/.....
clock = new Timer(1000, this);
clock.addActionListener(this);

这是它更新的地方（在 actionListener 方法中）：

if(event.getSource() == clock){
        if(seconds > 0 && seconds < 60){
            seconds--;
        }else{
            if(seconds == 0 && minutes != 0){
                seconds = 59;
                minutes--;
            }else{
                if(minutes == 0){
                    clock.stop();
                    Toolkit.getDefaultToolkit().beep();
                }
            }
        }
        if(seconds < 10){
            clockLabel.setText(minutes + ":0" + seconds);
        }else{
        clockLabel.setText(minutes + ":" + seconds);
        }
    }

以下是我的程序的所有代码：

import javax.swing.*;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.Timer;
public class BasketballScoreboard extends JFrame implements ActionListener{
/**
 * 
 */
private static final long serialVersionUID = 1L;
JPanel panel;
JButton exit;//Button to exit program
JButton resetScores;//Button to reset both scores
Timer clock;
JLabel score;
JLabel fouls;
JLabel addOne;
JLabel addTwo;
JLabel addThree;
JLabel addFouls;
JLabel bonus;
JLabel homeBonus;
JLabel awayBonus;
JLabel clockLabel;
JLabel clockControls;
JButton resetFouls;
JButton addHomeFoul;
JButton addAwayFoul;
JButton home2;//Button to add 2 points to home score
JButton home1;//Button to add 1 points to home score
JButton home3;//Button to add 3 points to home score
JButton away1;//Button to add 1 points to away score
JButton away2;//Button to add 2 points to away score
JButton away3;//Button to add 3 points to away score
JButton startClock;
JButton stopClock;
JLabel home;//Home team name
JLabel away;//Away team name
JLabel homeFouls;
JLabel awayFouls;
private int homeFoulsNum = 0;
private int awayFoulsNum = 0;
JLabel homeScore;//Home score
JLabel awayScore;//Away Score
private int homeScoreNum = 0;
private int awayScoreNum = 0;
private int seconds = 00;
private int minutes = 8;
public BasketballScoreboard(){
    GridLayout scoreboardLayout = new GridLayout(14,3);
    panel = new JPanel();
    exit = new JButton("Exit");
    exit.setHorizontalAlignment(SwingConstants.CENTER);
    exit.addActionListener(this);
    clockLabel = new JLabel(minutes + ":0" + seconds);
    clockLabel.setHorizontalAlignment(SwingConstants.CENTER);
    clock = new Timer(1000, this);
    clock.addActionListener(this);
    startClock = new JButton("Start Clock");
    startClock.setHorizontalAlignment(SwingConstants.CENTER);
    startClock.addActionListener(this);
    clockControls = new JLabel("Clock Controls: ");
    clockControls.setHorizontalAlignment(SwingConstants.CENTER);
    stopClock = new JButton("Stop Clock");
    stopClock.setHorizontalAlignment(SwingConstants.CENTER);
    stopClock.addActionListener(this);
    score = new JLabel("Score: ");
    score.setHorizontalAlignment(SwingConstants.CENTER);
    fouls = new JLabel("Fouls: ");
    fouls.setHorizontalAlignment(SwingConstants.CENTER);
    bonus = new JLabel("Bonus: ");
    bonus.setHorizontalAlignment(SwingConstants.CENTER);
    homeBonus = new JLabel("");
    homeBonus.setHorizontalAlignment(SwingConstants.CENTER);
    awayBonus = new JLabel("");
    awayBonus.setHorizontalAlignment(SwingConstants.CENTER);
    addFouls = new JLabel("Add Foul: ");
    addFouls.setHorizontalAlignment(SwingConstants.CENTER);
    addOne = new JLabel("+1: ");
    addOne.setHorizontalAlignment(SwingConstants.CENTER);
    addTwo = new JLabel("+2: ");
    addTwo.setHorizontalAlignment(SwingConstants.CENTER);
    addThree = new JLabel("+3: ");
    addThree.setHorizontalAlignment(SwingConstants.CENTER);

    resetScores = new JButton("Reset Scores");
    resetScores.setHorizontalAlignment(SwingConstants.CENTER);
    resetScores.addActionListener(this);
    resetFouls = new JButton("Reset Fouls");
    resetFouls.setHorizontalAlignment(SwingConstants.CENTER);
    resetFouls.addActionListener(this);
    home = new JLabel(JOptionPane.showInputDialog("Enter Home Team Name"));
    home.setHorizontalAlignment(SwingConstants.CENTER);
    away = new JLabel(JOptionPane.showInputDialog("Enter Away Team Name"));
    away.setHorizontalAlignment(SwingConstants.CENTER);
    home1 = new JButton("Home +1");
    home1.setHorizontalAlignment(SwingConstants.CENTER);
    home1.addActionListener(this);

    home2 = new JButton("Home +2");
    home2.setHorizontalAlignment(SwingConstants.CENTER);
    home2.addActionListener(this);
    home2.setMnemonic('h');
    home3 = new JButton("Home +3");
    home3.setHorizontalAlignment(SwingConstants.CENTER);
    home3.addActionListener(this);
    addHomeFoul = new JButton("Home Foul +1");
    addHomeFoul.setHorizontalAlignment(SwingConstants.CENTER);
    addHomeFoul.addActionListener(this);
    addAwayFoul = new JButton("Away Foul +1");
    addAwayFoul.setHorizontalAlignment(SwingConstants.CENTER);
    addAwayFoul.addActionListener(this);
    away1 = new JButton("Away + 1");
    away1.setHorizontalAlignment(SwingConstants.CENTER);
    away1.addActionListener(this);
    away2 = new JButton("Away +2");
    away2.addActionListener(this);
    away2.setHorizontalAlignment(SwingConstants.CENTER);
    away2.setMnemonic('a');
    away3 = new JButton("Away +3");
    away3.setHorizontalAlignment(SwingConstants.CENTER);
    away3.addActionListener(this);
    homeScore = new JLabel("" + homeScoreNum);
    homeScore.setHorizontalAlignment(SwingConstants.CENTER);
    awayScore = new JLabel("" + awayScoreNum);
    awayScore.setHorizontalAlignment(SwingConstants.CENTER);
    homeFouls = new JLabel("" + homeFoulsNum);
    homeFouls.setHorizontalAlignment(SwingConstants.CENTER);
    awayFouls = new JLabel("" + awayFoulsNum);
    awayFouls.setHorizontalAlignment(SwingConstants.CENTER);
    panel.setLayout(scoreboardLayout);
    panel.add(new JLabel(""));
    panel.add(clockLabel);
    panel.add(new JLabel(""));
    panel.add(new JLabel(""));
    panel.add(home);
    panel.add(away);

    panel.add(score);
    panel.add(homeScore);
    panel.add(awayScore);
    panel.add(fouls);
    panel.add(homeFouls);
    panel.add(awayFouls);
    panel.add(bonus);
    panel.add(homeBonus);
    panel.add(awayBonus);
    panel.add(addOne);
    panel.add(home1);
    panel.add(away1);
    panel.add(addTwo);
    panel.add(home2);
    panel.add(away2);
    panel.add(addThree);
    panel.add(home3);
    panel.add(away3);
    panel.add(new JLabel(""));
    panel.add(new JLabel(""));
    panel.add(new JLabel(""));
    panel.add(addFouls);
    panel.add(addHomeFoul);
    panel.add(addAwayFoul);
    panel.add(clockControls);
    panel.add(startClock);
    panel.add(stopClock);

    panel.add(new JLabel(""));
    panel.add(new JLabel(""));
    panel.add(new JLabel(""));
    panel.add(resetScores);
    panel.add(resetFouls);
    panel.add(exit);
    this.add(panel);
}
@Override
public void actionPerformed(ActionEvent event){
    if(event.getSource() == home1){
        homeScoreNum++;
        homeScore.setText("" + homeScoreNum);
    }
    if(event.getSource() == home2){
        homeScoreNum += 2;
        homeScore.setText("" + homeScoreNum);
    }
    if(event.getSource() == home3){
        homeScoreNum += 3;
        homeScore.setText("" + homeScoreNum);
    }
    if(event.getSource() == addHomeFoul){
        homeFoulsNum ++;
        homeFouls.setText("" + homeFoulsNum);
        if(homeFoulsNum >= 6 && homeFoulsNum < 9){
            homeBonus.setText("u2713");
        }
        if(homeFoulsNum >= 9){
            homeBonus.setText("u2713u2713");
        }
    }
    if(event.getSource() == away1){
        awayScoreNum++;
        awayScore.setText("" + awayScoreNum);
    }
    if(event.getSource() == away2){
        awayScoreNum += 2;
        awayScore.setText("" + awayScoreNum);
    }
    if(event.getSource() == away3){
        awayScoreNum += 3;
        awayScore.setText("" + awayScoreNum);
    }
    if(event.getSource() == addAwayFoul){
        awayFoulsNum++;
        awayFouls.setText("" + awayFoulsNum);
        if(awayFoulsNum >= 6 && awayFoulsNum < 9){
            awayBonus.setText("u2713");
        }
        if(awayFoulsNum >= 9){
            awayBonus.setText("u2713u2713");
        }
        }
    if(event.getSource() == exit){
        System.exit(0);     }
    if(event.getSource() == resetScores){
        homeScoreNum = 0;
        awayScoreNum = 0;
        homeScore.setText("" + homeScoreNum);
        awayScore.setText("" + awayScoreNum);
    }
    if(event.getSource() == resetFouls){
        homeFoulsNum = 0;
        awayFoulsNum = 0;
        homeFouls.setText("" + homeFoulsNum);
        awayFouls.setText("" + awayFoulsNum);
        homeBonus.setText("");
        awayBonus.setText("");
    }
    //Here is where the event handling for the timer comes in.
            //I believe this is where the problem is.
             if(event.getSource() == clock){
        if(seconds > 0 && seconds < 60){
            seconds--;
        }else{
            if(seconds == 0 && minutes != 0){
                seconds = 59;
                minutes--;
            }else{
                if(minutes == 0){
                    clock.stop();
                    Toolkit.getDefaultToolkit().beep();
                }
            }
        }
        if(seconds < 10){
            clockLabel.setText(minutes + ":0" + seconds);
        }else{
        clockLabel.setText(minutes + ":" + seconds);
        }
    }
    if(event.getSource() == startClock){
        clock.start();
    }
    if(event.getSource() == stopClock){
        clock.stop();
    }

}
public static void main(String[] args){
    BasketballScoreboard first = new BasketballScoreboard();
    first.setTitle("Scoreboard");
    first.setSize(350, 300);
    first.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    first.setVisible(true);
}
}

Answer 1

您的问题在下一行：

clock = new Timer(1000, this);
clock.addActionListener(this);

您添加ActionListener 2 次，因此您的代码执行 2 次。因此，删除clock.addActionListener(this);，一切都会起作用。