为什么图像不显示在 JPanel 上？

Question

I want to draw an image on a JPanel which is displayed on a JFrame . I tested the paint method without the frame and it seemed to work, but as soon as I added the image on the frame it won't get shown. Instead I only see a very small square which displays a small area of the image.

Here's my code so far:

TestFrame class:

public class TestFrame extends JFrame {
    private JFrame frame = new JFrame();
    private JPanel jp = new JPanel();
    
    public MyFrame() {
        frame.setTitle("test");
        frame.setSize(300, 300);
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        
        frame.setLayout(new BorderLayout());
        
        jp.setBackground(Color.YELLOW);
        frame.add(jp, BorderLayout.CENTER);
        jp.add(new DrawPanel());
        jp.repaint();
        
        frame.setVisible(true);
    }   
}

DrawPanel class:

public class DrawPanel extends JPanel {
    private BufferedImage img;
    
    public DrawPanel() {
        try {
            img = ImageIO.read(getClass().getResourceAsStream("/resources/heart.jpg"));
        } 
        catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    @Override protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(img, 0, 0, null);
    }
}

Answer 1

在方法paintComponent()中尝试这个：

g.drawimage(img.getImage(), 0, 0, null);