Why Isn't My Extended JPanel's paintComponent() Method Being Called Despite Using repaint()?

Program not accessing method paintComponent() of extended JPanel class

Issue

The provided code features a JFrame and its corresponding JPanel extension. While the repaint() method of the JPanel is being called repeatedly, it fails to execute the paintComponent() method. This has led to the suspicion that the imageDimension object could be the source of the issue.

Solution

Although the supplied context doesn't explicitly reference byte arrays, it appears that the objective is to create grayscale thumbnails and assign them to a component's icon. The sample code below offers a method for converting existing sample icons to grayscale and using setIcon() to update the component. This approach can be applied to any image.

It's worth noting that the aforementioned grayscale conversion can be achieved using ColorConvertOp or by updating the component itself instead of its icon.

import java.awt.*;<br>import javax.swing.*;</p>
<p>public class IconExample {</p>
<pre class="brush:php;toolbar:false">public static void main(String[] args) {
    // Create a list of icons
    List<Icon> icons = new ArrayList<>();
    icons.add(new ImageIcon("image1.png"));
    icons.add(new ImageIcon("image2.png"));

    // Create a panel to hold the icons
    JPanel panel = new JPanel();
    panel.setLayout(new GridLayout(1, icons.size()));

    // Add the icons to the panel
    for (Icon icon : icons) {
        panel.add(new JLabel(icon));
    }

    // Create a frame for the panel
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(300, 300);
    frame.add(panel);

    // Make the frame visible
    frame.setVisible(true);

    // Create a timer to update the icons
    Timer timer = new Timer(1000, new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            // Shuffle the icons
            Collections.shuffle(icons);

            // Update the icons in the panel
            for (int i = 0; i < icons.size(); i++) {
                panel.getComponent(i).setIcon(icons.get(i));
            }

            // Repaint the panel
            panel.repaint();
        }
    });

    // Start the timer
    timer.start();
}

}

This example illustrates the use of Collections.shuffle to randomize icon order and updates the icons in the panel every second. The repaint() method ensures the changes are visible on the screen, and the icons are continuously updated.

By providing this alternative approach, we demonstrate that the issue related to the paintComponent() method might be unrelated to the imageDimension object and instead stems from the specific implementation of the graphics and image handling in your original code.

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