Question

我有一个半透明 JPanel。我通过扩展JButton创建了一个自定义JButton ，因为我需要一个带圆角的按钮，并希望为它添加一些效果。我已将按钮设为非不透明。当我将这个按钮添加到我的半透明JPanel时，它很好。但是在翻滚时，按钮后面会画一个黑色的补丁，看起来很糟糕。我在网上寻找解决方案但却找不到有用的解决方案。这个问题也在http://www.java.net/node/661798描述，但我无法真正让kirillcool的建议工作.....任何帮助将不胜感激

Answer 1

我相信你需要添加：

button.setContentAreaFilled( false );

Answer 2

不确定某人是否还有兴趣... 您可以通过覆盖paintComponent()方法来解决问题，让Java以您喜欢的任何形状绘制JButton。您只需要使用setBackground()方法将Graphics对象的背景设置为透明。您还需要在使用clearRect()方法绘制图形对象之前清除它，然后使用JButton背景的alpha级别再次填充它。这是我的代码片段..它显示了覆盖paintComponent()。通过将其粘贴到您的JButton中，您应该获得带有圆边的JButton，即使它在半透明背景上

private int outerRoundRectSize = 10;
private int innerRoundRectSize = 8;

public void paintComponent(Graphics g) 
{
    int h = getHeight();
    int w = getWidth();

    Graphics2D g2d = (Graphics2D) g.create();
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);

    Color GP = null;

    //////////////get rid of the black background////////////////////////
    g2d.setBackground(new Color(0,0,0,0.0f));
    g2d.clearRect(0, 0, w, h);
    g2d.setPaint(new Color(0,0,0,0.3f));
    g2d.fillRect(0, 0, w, h);
    //////////////get rid of the black background////////////////////////

    ButtonModel model = getModel();
    if(!model.isEnabled()) 
    {
        setForeground(Color.GRAY);
        GP = new Color(0.5f,0.2f,0.6f);
    }
    else
    {
        setForeground(Color.WHITE);
        if(model.isRollover()) 
        {
            GP = new Color(0.5f,0.2f,0.6f);
        } 
        else 
        {
            GP = new Color(0.0f,1.0f,0.0f);
        }   
    }
    g2d.setPaint(GP);
    Color p1 = null;
    Color p2 = null;

    if(getModel().isPressed()) 
    {
        GP = new Color(1.0f,0.0f,0.0f);
        g2d.setPaint(GP);
        p1=new Color(0.12f,0.7f,0.3f);
        p2=new Color(0.7f,0.5f,0.6f);
    } 
    else 
    {
        p1=new Color(0.0f,0.5f,0.7f);
        p2=new Color(0.0f,1.0f,1.0f);
        GP = new Color(0.0f,0.0f,1.0f);
    }

    RoundRectangle2D.Float r2d = new RoundRectangle2D.Float(0, 0, w - 1, h - 1, outerRoundRectSize, outerRoundRectSize);
    Shape clip = g2d.getClip();
    g2d.clip(r2d);
    //g2d.fillRect(0, 0, w, h);
    g2d.fillRoundRect(0, 0, w, h, outerRoundRectSize, outerRoundRectSize);
    g2d.setClip(clip);
    g2d.setPaint(p1);
    g2d.drawRoundRect(0, 0, w - 1, h - 1, outerRoundRectSize,outerRoundRectSize);
    g2d.setPaint(p2);
    g2d.drawRoundRect(1, 1, w - 3, h - 3, innerRoundRectSize,innerRoundRectSize);

    g2d.dispose();
    super.paintComponent(g);
}

透明的JButton仍在绘制它的背景

2 个答案: