javax.swing.Timer 的困难

Question

按下勾选按钮时出现运行时错误。当按下刻度按钮触发事件时，我正在尝试使用 javax.swing.Timer 所以如果有人有任何建议，我将不胜感激。我目前正在使用 Eclipse，按下勾选按钮时出现运行时错误。

线程“AWT-EventQueue-0”java.lang.Error 中的异常：未解决 编译问题：ClockPanel 类型必须实现继承的 抽象方法 ActionListener.actionPerformed(ActionEvent) 在 ClockPanel.actionPerformed(ClockPanel.java:10)

这是我正在使用的代码（3 个类）。

import java.util.Calendar;
import java.util.GregorianCalendar;

class Clock 
{
     int hour;
     int minute;
     int second;

     Calendar gregcal = new GregorianCalendar();
     int h = gregcal.get(Calendar.HOUR_OF_DAY);
     int m = gregcal.get(Calendar.MINUTE);
     int s = gregcal.get(Calendar.SECOND);

    //default constructor
    Clock()
    {
        hour = h;
        minute = m;
        second = s; 
    }

    //parameterized constructor
    Clock(int hour, int minute, int second)
    {
        this.hour = hour;
        this.minute = minute;
        this.second = second;      
    }

    public int getHour()
    {
        return hour;
    }

    public int getMinute()
    {
        return minute;
    }


    public int getSecond()
    {
        return second;
    }

    public String toString()
    {
        return "The time is: " + hour + ":" + minute + ":" + second ;    
    }   

    public void tick()
    {
        second += 1;
        if(second > 60)
        {
            second = 0;
            minute++;
        }
        if(minute > 60)
        {
            minute =0;
            hour++;
        }
        if(hour > 24)
        {
            hour = 0;
        }
        System.out.println(this.toString());
    }
}

// next class


import java.awt.*;
import java.util.Calendar;
import java.util.GregorianCalendar;

import javax.swing.*;

public class TestClock 
{
    public static void main(String[] args)
    {
        Calendar gregcal = new GregorianCalendar();
        int h = gregcal.get(Calendar.HOUR_OF_DAY);
        int m = gregcal.get(Calendar.MINUTE);
        int s = gregcal.get(Calendar.SECOND);

        Clock c = new Clock(h, m, s);

        JFrame application = new JFrame("Clock");
        ClockPanel panel = new ClockPanel(c);

        application.add(panel);
        application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        application.setSize(160,80);
        application.setVisible(true);  
    }

}


// the last class here is the problem
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JButton;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.Timer;

class ClockPanel extends JPanel implements ActionListener
{
    Clock myck = new Clock();
    private javax.swing.Timer timer;
    JTextField txt1, txt2, txt3;
    JLabel  jl1, jl2;
    JButton tick;
    JPanel top, buttom;



    ClockPanel(Clock ck)
    {

        this.setLayout(new GridLayout(2,1));
        top = new JPanel();
        top.setLayout(new GridLayout(1,5));

        String hour  = "" + ck.getHour(); // easier way  
        txt1 = new JTextField(hour);
        top.add(txt1);

        jl1 = new JLabel(" : ");
        top.add(jl1);

        String minute = Integer.toString(ck.getMinute()); // harder convertion
        txt2 = new JTextField(minute);
        top.add(txt2);

        jl2 = new JLabel(" : ");
        top.add(jl2);

        String second = Integer.toString(ck.getSecond());
        txt3 = new JTextField(second);
        top.add(txt3);
        this.add(top);


        buttom = new JPanel(new GridLayout(1,1));


        tick = new JButton("tick");
        buttom.add(tick);
        tick.addActionListener(this);
        this.add(buttom);

    }

    javax.swing.Timer t = new javax.swing.Timer(1000, new ActionListener() {



    public void actionPerformed(ActionEvent ae) 
    {

        if(ae.getSource().equals(tick))
        {

            myck.tick();
            txt1.setText(Integer.toString(myck.getHour()));
            txt2.setText(Integer.toString(myck.getMinute()));
            txt3.setText(Integer.toString(myck.getSecond()));   
        }   
    }
    });
    public void start()
    {
        t.start();
    }
}

Answer 1

根据我的 cmets，您的问题是您必须为 ClockPanel 类提供该类范围内的 actionPerformed 方法。您甚至不应该尝试运行无法编译的类，而应该在尝试运行代码之前先修复所有编译错误。