Black square showing when adding .GIF to JPanel

Question

My problem is that when adding .GIF to JPanel it shows this black square background for .GIF.

Result when adding to JPanel:

This happens when I use this line:

p2.add(loadBar); // where p2 = new JPanel();

However, when I add the same .GIF to the JFrame, there is no longer a black square. Like this:

jf.add(loadBar); // where jf = new JFrame();

Result when added to JFrame:

Part of the class code:

String loadLink = "http://i.imgur.com/mHm6LYH.gif";
        URL ajaxLoad = null;
        try {
            ajaxLoad = new URL(loadLink);
        } catch (MalformedURLException e3) {
            // TODO Auto-generated catch block
            e3.printStackTrace();
        }
        ImageIcon loading = new ImageIcon(ajaxLoad);
        JLabel loadBar = new JLabel(loading);
        loadBar.setBounds(70, 60, 54, 55);
        loadBar.setOpaque(false);
        //jf.add(loadBar);
        p2.add(loadBar);

Can someone explain why this is happening? Thanks for your time and reading.

EDIT:

// Creates the Initialization Panel
        p2 = new JPanel();
        // Sets the background, black with 125 as alpha value
        // This is less transparent
        p2.setLayout(null);
        p2.setBackground(new Color(0,0,0,150));
        // Sets a border to the JPanel
        p2.setBorder(new LineBorder(Color.WHITE));
        // Sets some size to the panels
        p2.setBounds(20, 20, 200, 150);

        // Adds the loading gif
        String loadLink = "http://i.imgur.com/mHm6LYH.gif";
        URL ajaxLoad = null;
        try {
            ajaxLoad = new URL(loadLink);
        } catch (MalformedURLException e3) {
            // TODO Auto-generated catch block
            e3.printStackTrace();
        }
        ImageIcon loading = new ImageIcon(ajaxLoad);
        JLabel loadBar = new JLabel(loading);
        loadBar.setBounds(70, 60, 54, 55);
        loadBar.setOpaque(false);
        p2.add(loadBar);

This is JPanel, which is shown in the first image without JLabel. I can not show the JFrame part in the code because it spreads throughout the class. But I don’t think the problem is with the JFrame, so this could be this JPanel: /

Answer 1

...

p2.setBackground(new Color(0,0,0,150));

Swing -, , .

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. setOpaque(false), , .

, , opaque false paintComponent -. AlphaComposite, ...

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.GridBagLayout;
import java.awt.HeadlessException;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;

public class TranslucentPanelExample {

    public static void main(String[] args) {
        new TranslucentPanelExample();
    }

    public TranslucentPanelExample() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                try {
                    JLabel background = new JLabel(
                            new ImageIcon(ImageIO.read(
                                            getClass().getResource("/background.jpg"))));
                    background.setLayout(new GridBagLayout());
                    background.add(new WaitPane());

                    JFrame frame = new JFrame("Testing");
                    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    frame.add(background);
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);
                } catch (IOException exp) {
                    exp.printStackTrace();
                }
            }
        });
    }

    public class WaitPane extends JPanel {

        public WaitPane() {
            setLayout(new GridBagLayout());
            setBorder(new EmptyBorder(12, 12, 12, 12));
            // This is very important
            setOpaque(false);
            setBackground(new Color(0, 0, 0, 150));

            String loadLink = "http://i.imgur.com/mHm6LYH.gif";
            URL ajaxLoad = null;
            try {
                ajaxLoad = new URL(loadLink);
            } catch (MalformedURLException e3) {
                // TODO Auto-generated catch block
                e3.printStackTrace();
            }

            ImageIcon loading = new ImageIcon(ajaxLoad);
            JLabel loadBar = new JLabel(loading);
            loadBar.setHorizontalAlignment(JLabel.CENTER);
            loadBar.setVerticalAlignment(JLabel.CENTER);
            add(loadBar);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.setColor(getBackground());
            g.fillRect(0, 0, getWidth(), getHeight());
        }

    }

}

, , ...

, . "" , ...

Answer 2

, . , , JFrame JPanel. :

import javax.swing.*;
import java.net.*;

public class Test {
public static void main(String[] args) {
    JFrame frame = new JFrame("Test");
    frame.setSize(600, 400);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    JPanel panel = new JPanel();
    String loadLink = "http://i.imgur.com/mHm6LYH.gif";
    URL ajaxLoad = null;
    try {
        ajaxLoad = new URL(loadLink);
    } catch (MalformedURLException e3) {
        e3.printStackTrace();
    }
    ImageIcon loading = new ImageIcon(ajaxLoad);
    JLabel loadBar = new JLabel(loading);
    loadBar.setBounds(70, 60, 54, 55);
    loadBar.setOpaque(false);
    panel.add(loadBar);    
    frame.add(panel);
    frame.setVisible(true);
    }
}

, , , - . GIF . , ? , , JFrame JPanel, ? .

Answer 3

.

Please see Monitoring with ImageObserver to check the status of the image.

Add the image to JPanelwhen it is fully loaded.

---

Code example:

    new Thread(new Runnable() {

        @Override
        public void run() {
            int width = loading.getIconWidth();

            if (width >= 0) {
                isImageLoaded = true;
                p2.add(loadBar);
                return;
            }

            // Wait if the image is not loaded yet
            while (!isImageLoaded) {
                try {
                    Thread.sleep(500);
                } catch (InterruptedException ie) {
                }
            }
        }
    }).start();