Java Swing paintComponent（）覆盖

Question

I want to set an Image as background in some JComponent ( JPanel , JLayeredPane ,..). To do that I created the class JImagePanel that extends JPanel and overrides the method. Same thing for the other components. I now have 3 classes that differ only for what they extend. I wanted to create a unique class JImageComponent that extends JComponent , and then all the others will extend it, but I can't since the classes I created already extend a class ( JImagePanel extends JPanel ). Is there any other way I can do that?

This is the code of one of the classes I created:

public class JImagePanel extends JPanel {

  private static final int DEFAULTX = 0;
  private static final int DEFAULTY = 0;
  private static final int DEFAULTWIDTH = 1100;
  private static final int DEFAULTHEIGHT = 700;

  private BufferedImage img;
  private int imagex;
  private int imagey;
  private int imagewidth;
  private int imageheight;
  private static final long serialVersionUID = 1L;

  public JImagePanel(String path){
        super();
        this.imagex=JImagePanel.DEFAULTX;
        this.imagey=JImagePanel.DEFAULTY;
        this.imagewidth=JImagePanel.DEFAULTWIDTH;
        this.imageheight=JImagePanel.DEFAULTHEIGHT;
        img = loadImage(path);
  }

  public JImagePanel(String path,int x,int y, int width, int height){
        super();
        this.imagex=x;
        this.imagey=y;
        this.imagewidth=width;
        this.imageheight=height;
        img = loadImage(path);
  }

  @Override
  protected void paintComponent(Graphics graphics) {
        super.paintComponent(graphics);

       setOpaque(false);
       graphics.drawImage(img, imagex, imagey,imagewidth,imageheight, null);
  }
}

Thank you.

Answer 1

What you are suggesting isn't logically possible since JPanel , JLayeredPane , etc. already extend JComponent . What you're trying to do is add a new step in the hierarchy. Right now it goes JImagePanel -->JPanel --> JComponent , etc. and you're trying to make it JImagePanel --> JPanel --> JImageComponent --> JComponent . To do this, you would have to change the JPanel class so it actually extends JImageComponent .

Here's my suggestion: Don't use JImageComponent on the classes that already extend components. If you make new components that don't extend pre-existing components, have them extend JImageComponent , or JComponent directly. If the purpose of your JImageComponent class was to provide unity to your elements, consider making an interface for all your elements to implement.