如何只显示图像使JFrame背景和JPanel透明化

嘿，我正在尝试制作某种发射器，“窗口”必须是透明的，因为如果你理解我的意思，我希望我用的图像是它的设计。 我试着做setUndecorated(true); 和setBackground(new Color(0, 0, 0, 0)); 但它看起来很奇怪。 这是一张关于它的外观的图片： http ： //prntscr.com/2pqohq这是我的代码：

 import java.awt.Color; import java.awt.Dimension; import java.awt.Graphics; import java.awt.GridBagLayout; import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import java.net.MalformedURLException; import java.util.logging.Level; import java.util.logging.Logger; import javax.imageio.ImageIO; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.SwingUtilities; /** * * Our Launcher for the client * * @author Daniel  * * Current Date: 5. feb. 2014 Current Time: 14:29:54 * Project: 742 client. File Name: Launcher.java * */ public class Launcher2 { public Launcher2() { JFrame frame = new JFrame(); frame.getContentPane().add(new ImagePanel()); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //frame.pack(); //had to remove, got an error from it... frame.setUndecorated(true); //transparent frame.setBackground(new Color(0, 0, 0, 0)); //transparent frame.setVisible(true); frame.setSize(1080, 550); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable(){ public void run() { new Launcher2(); } }); } @SuppressWarnings("serial") public class ImagePanel extends JPanel { BufferedImage img; public ImagePanel() { setLayout(new GridBagLayout()); try { img = ImageIO.read(new File("C:/Users/Daniel/Pictures/Launcher3.png/")); } catch (MalformedURLException ex) { Logger.getLogger(Launcher2.class.getName()).log(Level.SEVERE, null, ex); } catch (IOException ex) { Logger.getLogger(Launcher2.class.getName()).log(Level.SEVERE, null, ex); } } /** * Draws the image and sets the image dimension */ @Override protected void paintComponent(Graphics g) { super.paintComponent(g); //g.drawImage(img, 100, 100, 1080, 550, this); g.drawImage(img, 0, 0, getWidth(), getHeight(), this); } /** * Sets the JPanel dimension */ public Dimension getPreferredSize() { return new Dimension(1080, 550); } } } 

Answer 1

您需要将ImagePanel设置为setOpaque(false)

  public ImagePanel() { setOpaque(false); 

你也得到了exception，因为你需要在setUndecorate(true) 之前设置setUndecorate(true) pack();

  JFrame frame = new JFrame(); frame.add(new ImagePanel()); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setUndecorated(true); frame.pack(); frame.setBackground(new Color(0, 0, 0, 0)); frame.setVisible(true); 

这是我改变的唯一两件事，它起作用。 我也摆脱了setSize()

也可以使用frame.setLocationRelativeTo(null); 在pack()之后使框架居中。

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这是一个例子（仅供未来读者阅读，因为我认为这可能是一个热门话题）

 import java.awt.*; import java.awt.image.BufferedImage; import java.io.IOException; import java.net.URL; import java.util.logging.Level; import java.util.logging.Logger; import javax.imageio.ImageIO; import javax.swing.*; public class CircleSplashScreen { public CircleSplashScreen() { JFrame frame = new JFrame(); frame.getContentPane().add(new ImagePanel()); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setUndecorated(true); frame.pack(); frame.setLocationRelativeTo(null); frame.setBackground(new Color(0, 0, 0, 0)); frame.setVisible(true); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { new CircleSplashScreen(); } }); } @SuppressWarnings("serial") public class ImagePanel extends JPanel { BufferedImage img; public ImagePanel() { setOpaque(false); setLayout(new GridBagLayout()); try { img = ImageIO.read(new URL("http://www.iconsdb.com/icons/preview/royal-blue/stackoverflow-4-xxl.png")); } catch (IOException ex) { Logger.getLogger(CircleSplashScreen.class.getName()).log(Level.SEVERE, null, ex); } } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); g.drawImage(img, 0, 0, getWidth(), getHeight(), this); } @Override public Dimension getPreferredSize() { return new Dimension(500, 500); } } }