java - JButton 无法通过 GIF 正确显示

Question

我有一个程序，基本上应该是一些游戏的标题屏幕。背景是一个 GIF(我不确定这是否会导致问题)，我需要一些 JButtons 来让我运行实际的游戏。问题是 JButton 有时只在我将鼠标悬停在它上面时显示(并且是瞬间)，否则它是不可见的。它工作得很好，进入游戏等等，它只是隐形的。

我已经尝试查看问题是否出在我使用 GIF 以及 paintComponent() 方法这一事实上，但是，当我使用时它并没有出现使用了 JPEG。

代码如下:

public class TestingGrounds extends JFrame{
     //declarations
     JButton snakeButton;
     JPanel snakeButtonPanel;
     JFrame window;
     Container con;
     TitleScreenHandler tsHandler = new TitleScreenHandler();
     //constructor
     public TestingGrounds(){
          //main JFrame
          window = new JFrame("Title Screen");
          window.add(new ImagePanel());
          window.setResizable(false);
          window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          window.setSize(1831, 1030);
          window.setVisible(true);
          window.setLocationRelativeTo(null);
          window.setLayout(null);

          con = window.getContentPane();

          //panel for the button to go to the snake game
          snakeButtonPanel =  new JPanel();
          snakeButtonPanel.setBounds(100,100,600,150);

          //button to go to snake game
          snakeButton = new JButton("Snake");
          snakeButton.setBackground(Color.BLACK);
          snakeButton.setForeground(Color.WHITE);
          snakeButton.setFont(new Font("Times New Roman", Font.ITALIC, 30));
          snakeButton.addActionListener(tsHandler);
          snakeButton.setFocusPainted(false);
          //adding button to panel
          snakeButtonPanel.add(snakeButton);
          //adding panel to container
          con.add(snakeButtonPanel);
          //setting the panel as visible
          snakeButtonPanel.setVisible(true);

     }
     //main method for running constructor
     public static void main(String[] args) {
          new TestingGrounds();
     }

     //what to do if the button is pressed
     public class TitleScreenHandler implements ActionListener {
          public void actionPerformed(ActionEvent event){
               //goes to main game screen if start button is pressed
               new SnakeGame();
          }
     }
}
//class for using the gif
class ImagePanel extends JPanel {
     Image image;
     public ImagePanel() {
          image = Toolkit.getDefaultToolkit().createImage("C:/Users/eklut/Desktop/Coding/ICS4U1/src/graphicsstuff/snek/source.gif");
     }

     public void paintComponent(Graphics g) {
          super.paintComponent(g);
          g.drawImage(image, 0, 0, this);
     }
}

抱歉，我知道代码量很大，但我觉得我必须展示所有代码，因为我不确定问题出在哪里。

我原以为按钮会显示在 gif 上，但它似乎恰恰相反

Answer 1

此 MCVE 包含如此多的更改，最好仔细阅读代码并查看注释。

请注意，代码使用动画 GIF 作为 BG。我会说这是用来明确证明它是 GIF，但事实是示例图像页面仅包含动画 GIF。考虑到 PNG 将支持半透明和比 GIF 更多的颜色，这种格式对其他任何东西都没有太大好处。

import java.awt.*;
import java.awt.event.*;
import java.net.MalformedURLException;
import javax.swing.*;
import java.net.URL;

//public class TestingGrounds extends JFrame {
public class TestingGrounds {

    //declarations
    JButton snakeButton;
    JPanel snakeButtonPanel;
    JFrame window;
    TitleScreenHandler tsHandler = new TitleScreenHandler();

    //constructor
    public TestingGrounds() {
        //main JFrame
        window = new JFrame("Title Screen");
        try {
            JPanel imagePanel = new ImagePanel();
            imagePanel.setLayout(new BorderLayout());
            window.add(imagePanel);
            //window.setResizable(false);
            window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            // Don't guess sizes needed. They will be wrong on other 
            // PLAFs or platforms.
            //window.setSize(850, 600);

            // should be last
            //window.setVisible(true);
            window.setLocationRelativeTo(null);
            //window.setLayout(null);

            //con = window.getContentPane();
            //panel for the button to go to the snake game
            snakeButtonPanel = new JPanel(new GridBagLayout());
            snakeButtonPanel.setOpaque(false);
            //snakeButtonPanel.setBounds(100, 100, 600, 150);

            //button to go to snake game
            snakeButton = new JButton("Snake");
            snakeButton.setMargin(new Insets(10,40,10,40));
            snakeButton.setBackground(Color.BLACK);
            snakeButton.setForeground(Color.WHITE);
            snakeButton.setFont(new Font("Times New Roman", Font.ITALIC, 30));
            snakeButton.addActionListener(tsHandler);
            snakeButton.setFocusPainted(false);
            //adding button to panel
            snakeButtonPanel.add(snakeButton);
            //adding panel to container
            //con.add(snakeButtonPanel);
            // Adding the container to imagePanel
            imagePanel.add(snakeButtonPanel);

            //setting the panel as visible
            snakeButtonPanel.setVisible(true);

            window.pack();
            window.setVisible(true);
        } catch (MalformedURLException ex) {
            ex.printStackTrace();
        }
    }

    //main method for running constructor
    public static void main(String[] args) {
        new TestingGrounds();
    }

    //what to do if the button is pressed
    public class TitleScreenHandler implements ActionListener {

        public void actionPerformed(ActionEvent event) {
            //goes to main game screen if start button is pressed
            //new SnakeGame();
            JOptionPane.showMessageDialog(snakeButton, "Snake Game");
        }
    }
}
//class for using the gif

class ImagePanel extends JPanel {

    Image image;

    public ImagePanel() throws MalformedURLException {
        image = Toolkit.getDefaultToolkit().createImage(
                new URL("/image/OtTIY.gif"));
        MediaTracker mt = new MediaTracker(this);
        mt.addImage(image, 1);
        try {
            mt.waitForAll();
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(image, 0, 0, this);
    }

    @Override
    public Dimension getPreferredSize() {
        // this allows us to pack() the window around the image
        return (new Dimension(image.getWidth(this), image.getHeight(this)));
    }
}