How to change background image of JPanel

Question

Is it possible to change the Image of a JPanel after it was initialized?

Block.java (The JPanel to change img)

@SuppressWarnings("serial")
public class Block extends JPanel{

    private int rotation;

    public Block(){
    }

    @Override
    protected void paintComponent(Graphics g){ 
        super.paintComponent(g);    
        Graphics2D g2 = (Graphics2D) g;

        g2.drawImage(Images.greenBlock, 0, 0, null); 

    } 
}

Now i need a method like changeImage:

...
JPanel xy = new Block();

xy.changeImage(newImg); //I know this method does NOT exist

Thank you for your help

Answer 1

Change this:

JPanel xy = new Block();

to this:

Block xy = new Block();

and give Block a changeImage(newImg) method where you change the image that your variable greenBlock refers to. Within your changeImage method, don't forget to call repaint();

Question: why the break; statement within your paintComponent method?

---

e.g.,

public class Block extends JPanel{

    private int rotation;
    // if you wish to initialize it with greenBlock...
    private Image myImage = Images.greenBlock;

    public Block(){
    }

    @Override
    protected void paintComponent(Graphics g){ 
        super.paintComponent(g);    
        Graphics2D g2 = (Graphics2D) g;
        g2.drawImage(myImage, 0, 0, null);
    } 

    public void changeImage(Image img) {
        this.myImage = img;
        repaint();
    }
}