Wait()、Notify()、定时器和 Jbuttons

Question

我什至不知道如何解决这个问题，但是在阅读了一些内容并进行了很多尝试（失败）之后，我决定向社区寻求帮助。我有表单 A 打开并要求用户输入延迟表单 B 打开的时间。目前我正在使用sleep() 来执行此操作，但现在我想插入另一个对话框以允许用户在计时器用完之前中断计时器并调出表单 B。我相信正确的方法是使用wait() 和notify()，但我似乎无法理解生产者和消费者模型的众多示例。任何帮助表示赞赏。

Answer 1

javax.swing.Timer 的完美工作。详情请参阅How to Use Swing Timers。这是一个示例，可引导您朝着正确的方向前进。

import java.awt.*;
import java.awt.event.*;
import javax.swing.Timer;
import javax.swing.*;

public class TimerDemo extends JFrame implements ActionListener {

    private Timer timer;
    private JButton jbDoSomethingDelayed;
    private JButton jbDoItImmediately;

    public TimerDemo() {        
        setLayout(new FlowLayout());
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setTitle("Timer demo");

        jbDoSomethingDelayed = new JButton("Do something with a delay");
        jbDoItImmediately = new JButton("Do it. Do it NOW!");

        add(jbDoSomethingDelayed);
        add(jbDoItImmediately);

        jbDoItImmediately.setEnabled(false);

        timer = new Timer(0, this); // we override delay later
        timer.setRepeats(false); // we don't want it firing repeatedly

        jbDoSomethingDelayed.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String msg = "Enter delay and confirm dialog";
                JSpinner spinner = new JSpinner(new SpinnerNumberModel(5, 1, 10, 1));
                Object[] content = new Object[] {msg, spinner};
                int showConfirmDialog = JOptionPane.showConfirmDialog(TimerDemo.this, content, "Choose", JOptionPane.OK_CANCEL_OPTION);
                if (showConfirmDialog == JOptionPane.OK_OPTION) {
                    // the important part
                    timer.setInitialDelay(((Integer)spinner.getValue()) * 1000);                    
                    jbDoSomethingDelayed.setEnabled(false);
                    jbDoItImmediately.setEnabled(true);
                    timer.start();
                }
            }
        });

        jbDoItImmediately.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                timer.stop();
                onTimerTimeout();
            }
        });

        pack();
        setLocationRelativeTo(null);
    }

    public void actionPerformed(ActionEvent e) {
        // called by timer on EDT, no worries here
        onTimerTimeout();
    }

    private void onTimerTimeout() {   
        jbDoSomethingDelayed.setEnabled(true);
        jbDoItImmediately.setEnabled(false);
        JOptionPane.showConfirmDialog(this, "You've done it now. No, really...", "It is done", JOptionPane.DEFAULT_OPTION, JOptionPane.INFORMATION_MESSAGE);        
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                TimerDemo demo = new TimerDemo();
                demo.setVisible(true);
            }
        });
    }
}

Answer 2

最简单的方法是做这样的事情

Thread a = new Thread(new Runnable(){
   public void run(){
      //do whatever display
      try{
        Thread.sleep(timeToShowBform);
      }
      catch(InterruptedException ex){
         //interrupted.
      }finally{
      //show form B
      SwingUtilities.invokeLater(...)

   }
});

class BRunnable implements Runnable{
public void run(){
 //if clicked, then this runnable is called.
 a.interrupt();
}
}

线程a 假设在sleep 被阻塞，然后在调用a.interrupt() 时唤醒a。