swing timer doesn't work properly [closed]

Answer 1

An example of using a Swing Timer to pause action for xxx seconds:

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

@SuppressWarnings("serial")
public class QuickTimerEg extends JPanel {
   private static final int TIMER_DELAY = 2000;
   private boolean buttonsWorking = true;
   private JButton btn1 = null;
   private JButton btn2 = null;
   private Timer swingTimer;

   public QuickTimerEg() {
      ActionListener btnListener = new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            btnActionPerformed(e);
         }
      };
      setLayout(new GridLayout(4, 4));
      for (int i = 0; i < 4; i++) {
         for (int j = 0; j < 4; j++) {
            JButton button = new JButton("   ");
            button.addActionListener(btnListener);
            add(button);
         }
      }
   }

   private void btnActionPerformed(ActionEvent e) {
      if (!buttonsWorking) {
         return;
      }
      JButton button = (JButton)e.getSource();
      button.setBackground(Color.blue);
      button.setEnabled(false);
      if (btn1 == null) {
         btn1 = button;
      } else {
         buttonsWorking = false;
         btn2 = button;
         swingTimer = new Timer(TIMER_DELAY, new ActionListener() {
            public void actionPerformed(ActionEvent e) {
               btn1.setBackground(null);
               btn2.setBackground(null);
               btn1.setEnabled(true);
               btn2.setEnabled(true);
               btn1 = null;
               btn2 = null;
               buttonsWorking = true;               
            }
         });
         swingTimer.setRepeats(false);
         swingTimer.start();
      }
   }

   private static void createAndShowGui() {
      JFrame frame = new JFrame("QuickTimerEg");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(new QuickTimerEg());
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

Answer 2

As an aside, you might want to look at using List<Icon> and List<GameButton>. Such Collections are easy to shuffle in a reliable way. Also, note the difference between an individual GameButton and a collection of them, external to the GameButton class. It's the collection that you'll need to examine when any one button is clicked.

import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JToggleButton;
import javax.swing.Timer;
import javax.swing.UIManager;

/** @see http://stackoverflow.com/questions/7933424 */
public class ButtonTimer extends JPanel {

    private List<Icon> list = new ArrayList<Icon>();
    private List<GameButton> buttons = new ArrayList<GameButton>();
    private Timer timer = new Timer(1000, new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            createPanel();
        }
    });

    public ButtonTimer() {
        this.setLayout(new GridLayout(1, 0));
        list.add(UIManager.getIcon("OptionPane.errorIcon"));
        list.add(UIManager.getIcon("OptionPane.informationIcon"));
        list.add(UIManager.getIcon("OptionPane.warningIcon"));
        list.add(UIManager.getIcon("OptionPane.questionIcon"));
        createPanel();
        timer.start();
    }

    private void createPanel() {
        Collections.shuffle(list);
        this.removeAll();
        for (Icon icon : list) {
            GameButton gb = new GameButton(icon);
            buttons.add(gb);
            this.add(gb);
        }
        this.revalidate();
    }

    class GameButton extends JToggleButton {

        private Icon icon;

        public GameButton(Icon icon) {
            super(icon);
            this.icon = icon;
        }
    }

    private void display() {
        JFrame f = new JFrame("ButtonTimer");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(this);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new ButtonTimer().display();
            }
        });
    }
}

Answer 3

I don't know what you want to do, but you pass this as argument to the Timer constructor. This means that every 2 seconds, the actionPerformed method of this (instance of ConcentrationGame4) will be called. And the first thing that this method does is

GameButton button = (GameButton) e.getSource();

Obviously, this will throw an exception, since the origin of the event won't be a game button, but the timer.

To understand what a Timer does and how it works, it's very simple. You just have to read its api doc : http://download.oracle.com/javase/6/docs/api/javax/swing/Timer.html. This doc will even lead you to a tutorial explaining how they work, with examples.