一个jframe的背景contentPane干扰了它上面的jpanel

Question

我有一个jframe，上面有一个jpanel，这个panel经常需要用repaint（）和revalidate（）更改它的内容。我已经设法将图像、文本和按钮按我希望的方式放置在这个JPanel上。一切都在工作，但现在我试图为jframe设置一个背景，这不会干扰上面的内容。例如，如果有一个树的绘图，它应该出现在jpanel的文本后面，而不会破坏它。我发现semi的工作原理是在jframe上使用setContentPane()，添加一个类，它扩展了jpanel并覆盖了paintComponent（）。所有内容都出现在屏幕上，但文本被垂直压扁，元素被移到框架的顶部。

如果我不使用setContentPane（）而是将background类添加到框架中，那么无论JPanel的setOpaque（）如何，它都不会出现。我还尝试使用jLayeredPane，因为我在internet上读到的东西表明这是正确的答案。然而，我无法让它工作，背景仍然隐藏。

private final int WIDTH = 1024;
private final int HEIGHT = 768;    

Frame()
{
    JFrame frame = new JFrame();
    panel = new JPanel();
    gbc = new GridBagConstraints();

    //Unrelated elements
    //font = new Font(Font.MONOSPACED, Font.PLAIN, 20);
    //border = BorderFactory.createEmptyBorder();
    //imageResizer = new ImageResizer();

    frame.setTitle("Shady Path");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(WIDTH, HEIGHT);
    frame.setLocationRelativeTo(null);
    frame.setResizable(false);
    frame.setIconImage(new ImageIcon("res/human.png").getImage());
    frame.setContentPane(new DrawPanel());

    panel.setLayout(new GridBagLayout());
    panel.setOpaque(false);
    gbc.anchor = GridBagConstraints.PAGE_START;

    frame.add(panel);
    frame.setVisible(true);
 }

 //One of the two methods that change the contents of the jpanel
 void appendMain(String mainImage, JTextArea mainText, JButton button)
 {
    panel.removeAll();

    image = new JLabel(imageResizer.resize(200, 200, mainImage));
    gbc.insets = new Insets(0, 0, 30, 0);
    gbc.gridwidth = GridBagConstraints.REMAINDER;
    panel.add(image, gbc);

    formatText(mainText);
    panel.add(mainText, gbc);

    button.setFont(font);
    button.setForeground(Color.WHITE);
    button.setBackground(Color.BLACK);
    button.setBorder(border);
    gbc.fill = GridBagConstraints.VERTICAL;
    gbc.insets = new Insets(50, 0, 70, 0);
    panel.add(button, gbc);

    panel.revalidate();
    panel.repaint();
 }

 //This is for the text formating
 private void formatText(JTextArea baseText)
 {
    baseText.setEditable(false);
    baseText.setForeground(Color.WHITE);
    baseText.setFont(font);
    baseText.setLineWrap(true);
    baseText.setWrapStyleWord(true);
    baseText.setMargin(new Insets(0, 300, 0, 300));
    baseText.setOpaque(false);

    gbc.insets = new Insets(30, 0, 0, 0);
    gbc.weightx = 1;
    gbc.fill = GridBagConstraints.HORIZONTAL;
 }

 //The following code is for the paintComponent() class 
 //The imageResizer is another class that I made, but it just resizes images and it is unrelated.
 public class DrawPanel extends JPanel
 {
    private Image image;

 public DrawPanel()
 {
    ImageResizer imageResizer = new ImageResizer();
    ImageIcon imageIcon = imageResizer.resize(1024, 768, "res/test.png");
    image = imageIcon.getImage();
 }

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

Answer 1

嗯...看起来@hovercraftfullofeels的评论是对的。实际上，我只需要将DrawPanel的布局设置为BorderLayout，一切都修复了。

 public DrawPanel()
 {
    this.setLayout(new BorderLayout());

    ImageResizer imageResizer = new ImageResizer();
    ImageIcon imageIcon = imageResizer.resize(1024, 768, "res/test.png");
    image = imageIcon.getImage();
 }