CODEWITHSUNDEEP
javaswingjpanel
user1315621
user1315621

Reputation: 3372

Draw JPanel into JPanel

I have two classes that extend JPanel: MapPanel and CityPanel. I am trying to draw a CityPanel into a MapPanel but nothing appears. I do not understand why if I add a JButton in the same way it will be displayed perfectly. Here's the code:

public class PanelMap extends JPanel {

    public PanelMap() {
        CityPanel city = new CityPanel();
        city.setVisible(true);
        this.add(city);
    }

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

}



public class CityPanel extends JPanel {

    private BufferedImage image;

    public CityPanel() {
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawString("Test", 0, 0);     }

}

EDIT:

I have this code in CityMap. It display the string but no the image.

public CityPanel(String filePath, int red, int green, int blue) {
        this.image = colorImage(filePath, red, green, blue);
        this.setSize(100, 100);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(image, 50, 50, null); 
        g.drawString("sdjkfpod", 50, 50);
    }

Upvotes: 0

Views: 117

Answers (1)

Sanjeev Saha
Sanjeev Saha

Reputation: 2652

Could you please replace your following constructor of PanelMap.java:

public PanelMap() {
  CityPanel city = new CityPanel();
  city.setVisible(true);
  this.add(city);
}

By following constructor:

public PanelMap() {
    String filePath = "C:\\...\\city2.png";
    CityPanel city = new CityPanel(filePath, 0, 255, 255);       
    this.setLayout(new BorderLayout());
    this.add(city, BorderLayout.CENTER);        
}

and see the result?

Following changes have been made to your code:

  • The statement city.setVisible(true); is removed since it is not required at all.
  • The statement this.add(city); was indeed adding CityPanel to PanelMap but CityPanel took up very small space and looked as a very small rectangle. This is the reason the BorderLayout has been used.

Following PanelMapDemo.java adds PanelMap to a JFrame and creates an executable example.

public class PanelMapDemo extends javax.swing.JFrame {
private static final long serialVersionUID = 1L;

public static void main(String[] args) {
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            PanelMapDemo demoFrame = new PanelMapDemo("PanelMapDemo");
            demoFrame.setVisible(true);
        }
    });
}

public PanelMapDemo(String title) {
    super(title);
    setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);
    add(new PanelMap());
    setSize(new java.awt.Dimension(400, 200));
    setLocationRelativeTo(null);
 }
}

On my system when the original picture was:

enter image description here

Your MapPanel changes the picture to:

enter image description here

Hope, this helps.

Upvotes: 1

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