java - 悬停/单击时使 JButton 变暗

Question

ImageIcon backpackImageIcon = new ImageIcon("images/gui/button_backpack.png");
JButton backpackButton = new JButton();
backpackButton.setBounds(660,686,33,33);
backpackButton.setBorderPainted(false);
backpackButton.setFocusPainted(false);
backpackButton.setVisible(true);
backpackButton.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke("B"), "backpackButtonPress");
backpackButton.getActionMap().put("backpackButtonPress", ClassBackpackButton);
backpackButton.setAction(ClassBackpackButton);
backpackButton.setIcon(backpackImageIcon);
backpackButton.setToolTipText("Backpack[B]");
panel.add(backpackButton);      

我有多个按钮按照这种方式设置。我希望能够做的是让它们在悬停时变暗 10%，在点击时变暗 20%。我试图四处寻找如何做到这一点，但没有运气(只找到了 javascript 的东西)。抱歉，如果之前有人问过这个问题，感谢您的帮助。

** 编辑 **

我尝试过这样做，但它只是将图像变成空白:

BufferedImage bufferedImage = null;
try {
    bufferedImage = ImageIO.read(new File("images/gui/button_backpack.png"));
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}
BufferedImage darkerBackpackBufferedImage = new BufferedImage(32, 32, BufferedImage.TYPE_BYTE_INDEXED);
RescaleOp op = new RescaleOp(1.3f, 0, null);
darkerBackpackBufferedImage = op.filter(bufferedImage, null);
ImageIcon darkerBackpackImageIcon = new ImageIcon((Image) darkerBackpackBufferedImage);
backpackButton.setRolloverIcon((ImageIcon) darkerBackpackImageIcon);

** 编辑 ** 包含解决方案

这是我为阅读上面这篇文章的任何人提供的修改后的 shiftColor 函数...祝你好运:)

public BufferedImage shiftColor(BufferedImage img, int rShift, int gShift, int bShift) {
    Color tmpCol;
    int tmpRed, tmpGreen, tmpBlue;
    for (int x = 0; x < img.getWidth(); x++) {
        for (int y = 0; y < img.getHeight(); y++) {
            tmpCol=new Color(img.getRGB(x,y));
            tmpRed = (tmpCol.getRed()-rShift < 0) ? 0 : tmpCol.getRed()-rShift; //if shifted color is less than 0 change to 0
            tmpGreen = (tmpCol.getGreen()-gShift < 0) ? 0 : tmpCol.getGreen()-gShift; //if shifted color is less than 0 change to 0
            tmpBlue = (tmpCol.getBlue()-bShift < 0) ? 0 : tmpCol.getBlue()-bShift; //if shifted color is less than 0 change to 0
            tmpCol=new Color(tmpRed, tmpGreen, tmpBlue);
            img.setRGB(x,y,tmpCol.getRGB());
        }
    }
    return img;
}

Answer 1

有两种方法

1) 使用built-in methods in JButtons API

button.setIcon((Icon i));
button.setRolloverIcon((Icon i));
button.setPressedIcon(Icon i));
button.setDisabledIcon(Icon i));

2) 使用ButtonModel