java - 自动关闭对话框

Question

我对 JOptionPane 有疑问，如何自动关闭对话框，我可以使用该对话框在事件中提醒用户并在延迟后自动关闭，而无需关闭对话框？

public class ShutdownComputer
{  
    public static void main(String[]args)  
    {  
        int wholeTimeBeforeShutdown=0;  

        int hour=0;  
        int minute=0;  
        int second=0;  

        try  
        {  
            String a=JOptionPane.showInputDialog(null,"HOUR","HOUR BEFORE SHUTDOWN",JOptionPane.QUESTION_MESSAGE);  
            String b=JOptionPane.showInputDialog(null,"MINUTE","MINUTE BEFORE SHUTDOWN",JOptionPane.QUESTION_MESSAGE);  
            String c=JOptionPane.showInputDialog(null,"SECOND","SECOND BEFORE SHUTDOWN",JOptionPane.QUESTION_MESSAGE);  

            if((a==null)||(a.equals("")))  
            {  
                a="0";  
            }  

            if((b==null)||(b.equals("")))  
            {  
                b="0";  
            }  

            if((c==null)||(c.equals("")))  
            {  
                c="0";  
            }  

            int e=Integer.parseInt(a);  
            int f=Integer.parseInt(b);  
            int g=Integer.parseInt(c);  

            wholeTimeBeforeShutdown=wholeTimeBeforeShutdown+((e*60)*60);  
            wholeTimeBeforeShutdown=wholeTimeBeforeShutdown+(f*60);  
            wholeTimeBeforeShutdown=wholeTimeBeforeShutdown+(g);  

            wholeTimeBeforeShutdown=wholeTimeBeforeShutdown*1000;  


            Thread.sleep(wholeTimeBeforeShutdown);  

            JOptionPane.showMessageDialog(null, "You only have less than 2 minutes left"); 

            Runtime.getRuntime().exec("shutdown -r -f -t 120");  
        }  
        catch(Exception exception)  
        {  
            exception.printStackTrace();  
        }  
    }  
}

Answer 1

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.concurrent.TimeUnit;

import javax.swing.JDialog;
import javax.swing.JOptionPane;
import javax.swing.Timer;

…

    final String msg="Shutdown\nWill happen automatically in "; 
    final JOptionPane op=new JOptionPane(null, JOptionPane.INFORMATION_MESSAGE);
    final JDialog d=op.createDialog("Shutdown");
    d.setModal(true);
    // deadline in three hours:
    final long deadline=System.nanoTime()+TimeUnit.HOURS.toNanos(3);
    ActionListener updater=new ActionListener() {
      public void actionPerformed(ActionEvent e)
      {
        long left=deadline-System.nanoTime();
        if(left<=0) {
          d.dispose();
          return;
        }
        String time;
        long t=TimeUnit.NANOSECONDS.toHours(left);
        if(t>0) time=t>1? t+" hours": "one hour";
        else {
          t=TimeUnit.NANOSECONDS.toMinutes(left);
          time=t>1? t+" minutes": "one minute";
        }
        op.setMessage(msg+time);
      }
    };
    updater.actionPerformed(null);//update initial message
    d.pack(); // resize dialog for the updated message
    final Timer t=new Timer(1000, updater);
    t.setInitialDelay(0);
    t.setRepeats(true);
    t.start();
    d.setVisible(true);
    t.stop();
    // do your action

请注意，此代码发出的消息将向下舍入时间值，但我认为这对您来说是一个可用的起点。