Question

有多少技巧可以多次调用JFrame.setGlassPane(Component)吗？在下面的代码中，我首先调用它在玻璃窗格中创建一个红色框。这很好。然后，在鼠标单击处理程序中，我再次调用它以在新的玻璃窗格中创建一个蓝色框。这不起作用。原始的红色玻璃窗格消失，但不显示蓝色玻璃窗格。我在这里做错了什么？

public class GlassPaneProblem extends Component {

    private BufferedImage img;
    private JFrame f;

    public void paint(Graphics g) {
        g.drawImage(img, 0, 0, null);
    }

    public GlassPaneProblem() {
        try {
            img = ImageIO.read(new File("images/AppleCorps.JPG"));
        } catch (IOException e) {
        }
        this.addMouseListener(new MouseAdapter() {
            public void mouseClicked(MouseEvent e) {
                BlueGlassPane blueGlassPane = new BlueGlassPane();
                setTheGlassPane(blueGlassPane);
            }
        });
    }

    public Dimension getPreferredSize() {
        if (img == null) {
            return new Dimension(100, 100);
        } else {
            return new Dimension(img.getWidth(null), img.getHeight(null));
        }
    }

    public void run() {
        f = new JFrame("Glass Pane Problem");

        f.add(this);
        f.pack();
        RedGlassPane redGlassPane = new RedGlassPane();
        setTheGlassPane(redGlassPane);
        f.setVisible(true);
    }

    void setTheGlassPane(JComponent glassPane) {
        f.setGlassPane(glassPane);
        f.getGlassPane().setVisible(true);
    }

    public static void main(String[] args) {
        GlassPaneProblem glassPaneProblem = new GlassPaneProblem();
        glassPaneProblem.run();
    }
}

class RedGlassPane extends JComponent {
    protected void paintComponent(Graphics g) {
        Rectangle clip = g.getClipBounds();
        g.setColor(Color.RED);
        g.fillRect(clip.x + clip.width / 3, clip.y + clip.height / 3,
            clip.width / 3, clip.height / 3);
    }
}

class BlueGlassPane extends JComponent {
    protected void paintComponent(Graphics g) {
        Rectangle clip = g.getClipBounds();
        g.setColor(Color.BLUE);
        g.fillRect(clip.x + clip.width / 3, clip.y + clip.height / 3,
            clip.width / 3, clip.height / 3);
    }
}

像这样调用repaint()并不能解决问题：

void setTheGlassPane(JComponent glassPane) {
    f.setGlassPane(glassPane);
    f.getGlassPane().setVisible(true);
    f.repaint();
}

Answer 1

在setTheGlassPane()中，将其添加为第一行：

f.getGlassPane().setVisible(false);

不止一次调用JFrame.setGlassPane（Component）

1 个答案: