How to stop a JButton going gray when disabled?

问题:

I have to write a card game. When a card is clicked a random card image is generated but because you can only click on the card once, the button is set to be disabled after clicked. How can I stop the card image from going gray once it's clicked so that the new generated card image is clearly visible?

//Actions performed when an event occurs
public void actionPerformed(ActionEvent e)
{

    if (e.getSource() == card1)
    {
    randomInteger();
    card1.setIcon(cardImages[randomInt]);
    card1.setEnabled(false);

    }
    else if (e.getSource() == card2)
    {
    randomInteger();
    card2.setIcon(cardImages[randomInt]);
    card2.setEnabled(false);
    }
    else if (e.getSource() == card3)
    {
    randomInteger();
    card3.setIcon(cardImages[randomInt]);
    card3.setEnabled(false);
    }
    else if (e.getSource() == card4)
    {
    randomInteger();
    card4.setIcon(cardImages[randomInt]);
    card4.setEnabled(false);
    }
    else
    {
    randomInteger();
    card5.setIcon(cardImages[randomInt]);
    card5.setEnabled(false);
    }

}

}

回答1:

You simply need to set the disabled icon of the button to the same value as the icon of the button. See this example:

On the left a button where I have set both icon and disabledIcon. On the right I have only set the icon:

import java.awt.BorderLayout;
import java.net.MalformedURLException;
import java.net.URL;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class TestDisabledButtons {

    public static final String CARD_URL = "http://assets0.wordansassets.com/wvc-1345850020/wordansfiles/images/2012/8/24/156256/156256_340.jpg";

    protected void createAndShowGUI() throws MalformedURLException {
        JFrame frame = new JFrame("Test button");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        ImageIcon imageIcon = new ImageIcon(new URL(CARD_URL));
        JButton button = new JButton(imageIcon);
        JButton button2 = new JButton(imageIcon);
        button.setDisabledIcon(imageIcon);
        button.setEnabled(false);
        button2.setEnabled(false);
        frame.add(button, BorderLayout.WEST);
        frame.add(button2, BorderLayout.EAST);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    new TestDisabledButtons().createAndShowGUI();
                } catch (MalformedURLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        });
    }

}