Question

我正在开发一个程序，它会计算点击按钮之前的时间我在使用Timer方面遇到了麻烦。我想要有类似的东西 00:00:00 - ＆gt; 00:00:01 - ＆gt; 00:00:02 ......等我的问题是

它停留在00:00:01

这是我的代码

Timer timer=new Timer(1000,null);


JLabel time=new JLabel("00:00:00");
timer.addActionListener(new ActionListener()
{
    @Override
    public void actionPerformed(ActionEvent e)
    {
         DecimalFormat df=new DecimalFormat("00");
         int h=0;
         int m=0;
         int s=0;
         s++;
         if(s==60)
         {
             m++;
             if(m==60)
             {
                  h++;
             }
         }
         time.setText(df.format(h)+":"+df.format(m)+":"+df.format(s));
         revalidate();
         repaint();
      }
   });
   timer.start();

Answer 1

您已在ActionListener ...

的上下文中将变量声明为局部变量

@Override
public void actionPerformed(ActionEvent e)
{
     DecimalFormat df=new DecimalFormat("00");
     int h=0;
     int m=0;
     int s=0;

这意味着每次actionPerformed变量都会重置为0 ...

尝试改为使用实例变量......

当你通过限制时，你也没有重置变量，例如......

s++;
if (s >= 60) {
    s = 0;
    m++;
    if (m >= 60) {
        h++;
        m = 0;
    }
}

作为替代方案，你可以维护一个单独的计数器，它作为已经过的秒数并使用一些模块数学来计算时间部分

private int count = 0;

//...

Timer timer = new Timer(1000, new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        count++;

        int hours = count / (60 * 60);
        float remainder = count % (60 * 60);
        float mins = remainder / (60);
        remainder = remainder % (60);
        float seconds = remainder;

        DecimalFormat df=new DecimalFormat("00");
        time.setText(df.format(hours) + ":" + df.format(mins) + ":" + df.format(seconds));

    }
});
timer.start();

这使得管理单个值然后决定如何最好地格式化它，而不是管理三个状态这一事实变得更加简单......恕我直言

Answer 2

如果我了解你，你应该先存储startTime -

final long startTime = System.currentTimeMillis();

然后使用它来计算actionPerformed()，

中的时间字段

DecimalFormat df = new DecimalFormat("00");
long endTime = System.currentTimeMillis();
long diff = endTime - startTime;
int h = (int) (diff) / (60*60*1000);
diff -= h * (60*60*1000);
int m = (int) (endTime-startTime) / (60*1000);
diff -= m * (60 * 1000);
int s = (int) (diff / 1000);

time.setText(df.format(h) + ":" + df.format(m)
    + ":" + df.format(s));
revalidate();
repaint();

修改

根据您的新要求，

替换

final long startTime = System.currentTimeMillis();

与

final Calendar startTime = Calendar.getInstance();

然后

DecimalFormat df = new DecimalFormat("00"); long endTime = System.currentTimeMillis(); long diff = endTime - startTime.getTimeInMillis(); int h = (int) (diff) / (60 * 60 * 1000); diff -= h * (60 * 60 * 1000); int m = (int) (endTime - startTime.getTimeInMillis()) / (60 * 1000); diff -= m * (60 * 1000); int s = (int) (diff / 1000);

如何更新已用时间

2 个答案: