java - 屏幕快照基于JPanel的位置和大小

我正在尝试对JPanel的功能进行截图，但保存后会得到黑色图像。

这是代码：

private void takeScreenshot(String print){
        JFileChooser c = new JFileChooser(getRealDesktop());
        FileFilter jpg = new FileNameExtensionFilter(".jpg", ImageIO.getReaderFileSuffixes());
        FileFilter jpeg = new FileNameExtensionFilter(".jpeg", ImageIO.getReaderFileSuffixes());
        FileFilter png = new FileNameExtensionFilter(".png", ImageIO.getReaderFileSuffixes());
        c.setFileFilter(png);
        c.setFileFilter(jpeg);
        c.setFileFilter(jpg);
        c.showSaveDialog(this);
        if(c.getSelectedFile() != null){
            String ssLoc = c.getSelectedFile().getAbsolutePath()+c.getFileFilter().getDescription();
            System.out.println(ssLoc);
            BufferedImage bufImg = new BufferedImage(ssWindow.getSize().width, ssWindow.getSize().height,BufferedImage.TYPE_INT_RGB);
            ssWindow.paint(bufImg.createGraphics());
            File imageFile = new File(ssLoc);
            try{
                imageFile.createNewFile();
                ImageIO.write(bufImg, "JPG", imageFile);
            }catch(Exception ex){
                System.err.println(ex);
            }
        }
    }

按下动作按钮如下所示：

this.setVisible(false);
takeScreenshot("ssTake");
this.setVisible(true);

如何使这项工作？

最佳答案

谢谢，吉尔伯特·勒布朗。

我重新编写了一些代码以使用机器人来执行此操作，现在代码如下所示：

private void takeScreenshot(String print){
        JFileChooser c = new JFileChooser(getRealDesktop());
        FileFilter jpeg = new FileNameExtensionFilter("JPEG (*.jpg;*.jpeg;*.jpe;*.jfif)", "jpg", "jpeg", "jpe", "jfif");
        c.setFileFilter(jpeg);
        c.showSaveDialog(this);
        if(c.getSelectedFile() != null){
            ssLoc = c.getSelectedFile().getAbsolutePath()+".jpg";
            try {
                Thread.sleep(150);
                Robot robot = new Robot();
                BufferedImage screenShot = robot.createScreenCapture(new Rectangle(ssWindow.getX(),ssWindow.getY(),ssWindow.getWidth(),ssWindow.getHeight()));
                ImageIO.write(screenShot, "JPG", new File(ssLoc));
                System.out.println(print);
            } catch (AWTException | IOException | InterruptedException ex) {
                Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }