javaswing

How to set an image as a background for Frame in Swing GUI of java?


I have created one GUI using Swing of Java. I have to now set one sample.jpeg image as a background to the frame on which I have put my components.How to do that ?


Solution

  • There is no concept of a "background image" in a JPanel, so one would have to write their own way to implement such a feature.

    One way to achieve this would be to override the paintComponent method to draw a background image on each time the JPanel is refreshed.

    For example, one would subclass a JPanel, and add a field to hold the background image, and override the paintComponent method:

    public class JPanelWithBackground extends JPanel {
    
      private Image backgroundImage;
    
      // Some code to initialize the background image.
      // Here, we use the constructor to load the image. This
      // can vary depending on the use case of the panel.
      public JPanelWithBackground(String fileName) throws IOException {
        backgroundImage = ImageIO.read(new File(fileName));
      }
    
      public void paintComponent(Graphics g) {
        super.paintComponent(g);
    
        // Draw the background image.
        g.drawImage(backgroundImage, 0, 0, this);
      }
    }
    

    (Above code has not been tested.)

    The following code could be used to add the JPanelWithBackground into a JFrame:

    JFrame f = new JFrame();
    f.getContentPane().add(new JPanelWithBackground("sample.jpeg"));
    

    In this example, the ImageIO.read(File) method was used to read in the external JPEG file.