为什么JPanel在变透明和播放GIF之前会出现一个黑色的矩形，有没有办法去掉它？ [关闭]

Question

我正在尝试制作一款游戏，每当播放某张卡片时，透明 GIF 就会弹出并播放，但每当它出现时，都会出现一个黑色矩形，然后再次变得透明并播放 GIF。它不会影响任何功能，但看起来有点烦人。

这是我的初始代码，创建一个创建面板的线程，播放 GIF，然后销毁面板：

public class UnoGUI{
    
    public static void main(String[] args) {
        // Makes a frame without borders
        JFrame pop = new JFrame();
        pop.setUndecorated(true);

        // Makes the Frame Itself Transparent.
        pop.setBackground(new Color(1.0f, 1.0f, 1.0f, 0.0f));

        // Makes a Square
        pop.setSize(230, 350);

        // Puts it in the Middle
        pop.setLocation(550, 250);

        // TEST
        JLabel label = new JLabel(); // Test

        // Gets the GIF (Black Square Occurs regardless of if it is a GIF or an Image)
        String arg = "coffee.png"; // special_gifs/Blue_Skip.gif

        ImageIcon icon = null;
        try {
            icon = new ImageIcon(arg);
        }
        catch (Exception e) {
            System.out.println("File Not Found");
        }
        label.setIcon(icon);
        pop.getContentPane().add(label);
        // END TEST

        // Makes it visible
        pop.setVisible(true);

        // Waits three seconds
        try {
            java.util.concurrent.TimeUnit.SECONDS.sleep(2);
        }
        catch (Exception e) {
            System.out.println("Popup Failed");
        }

        // Destroys the popup.
        pop.dispose();
    }
}

我已经尝试注释掉 GIF 本身以缩小问题范围，但矩形仍然会出现一瞬间：

public class UnoGUI{

    public static void main(String[] args) {       
        // Makes a frame without borders
        JFrame pop = new JFrame();
        pop.setUndecorated(true);

        // Makes the Frame Itself Transparent. 
        pop.setBackground(new Color(1.0f,1.0f,1.0f,0.0f));

        // Makes a Square
        pop.setSize(230, 350);

        // Puts it in the Middle
        pop.setLocation(550, 250);  

        // TEST 
        JLabel label = new JLabel (); // Test

        /*
        // COMMENTED OUT

        // Gets the GIF(Black Square Occurs regardless of if it is a GIF or an Image)
        String arg = "special_gifs/Blue_Skip.gif";
        ImageIcon icon = null;

        try {
            icon = new ImageIcon (arg);
        } catch (Exception e) {
            System.out.println("File Not Found");
        }

        label.setIcon(icon);
        // END COMMENT
        */

        pop.getContentPane().add(label);
        // END TEST

        // Makes it visible
        pop.setVisible(true);

        // Waits three seconds
        try {
            java.util.concurrent.TimeUnit.SECONDS.sleep(2);
        } catch (Exception e) {
            System.out.println("Popup Failed");
        }

        // Destroys the popup. 
        pop.dispose();
    }
}

但是当我注释掉整个标签时，黑色矩形在程序运行时消失了：

public class UnoGUI{

    public static void main(String[] args) { 
        // Makes a frame without borders
        JFrame pop = new JFrame();
        pop.setUndecorated(true);

        // Makes the Frame Itself Transparent. 
        pop.setBackground(new Color(1.0f,1.0f,1.0f,0.0f));

        // Makes a Square
        pop.setSize(230, 350);

        // Puts it in the Middle
        pop.setLocation(550, 250);  
        /*
        // COMMENTED OUT  
        // TEST
        JLabel label = new JLabel (); // Test

        // Gets the GIF(Black Square Occurs regardless of if it is a GIF or an Image)
        String arg = "special_gifs/Blue_Skip.gif";
        ImageIcon icon = null;

        try {
            icon = new ImageIcon (arg);
        } catch (Exception e) {
            System.out.println("File Not Found");
        }

        label.setIcon(icon);

        pop.getContentPane().add(label);
        // END COMMENT
        */
        // END TEST

        // Makes it visible
        pop.setVisible(true);

        // Waits three seconds
        try {
            java.util.concurrent.TimeUnit.SECONDS.sleep(2);
        } catch (Exception e) {
            System.out.println("Popup Failed");
        }

        // Destroys the popup. 
        pop.dispose();
       }
}

我认为这可能与标签加载有关，因为它只存在一秒钟，并且只有在标签被移除时才会消失，但我想知道是否有办法让它消失，这样它一直是透明的。