Question

这是我用来在J3D Canvas3D上绘制图像的代码：

    Graphics g = Canvas.getGraphics(); //Canvas is the Canvas3D
    g.drawImage(new ImageIcon("back/loadingscreen.png").getImage(),
            0, 0, Canvas);

但是每当我运行代码时，我都会在g.drawImage（）的行中得到一个NullPointerException。我不知道是什么导致了这个例外，我们将不胜感激。

Answer 1

您的ImageIcon为空请使用它来正确加载ImageIcon

 InputStream stream = this.getClass().getClassLoader().getResourceAsStream("back/loadingscreen.png");
     BufferedImage bufferedImage=ImageIO.read(stream);
     ImageIcon icon= new ImageIcon(bufferedImage);

     Graphics g = Canvas.getGraphics(); 
        g.drawImage(icon.getImage(), 0, 0, Canvas);

Answer 2

尝试这样的事情：

图形g = Canvas.getGraphics（）;

如果（克== NULL）{

System.out.println（“没有从getGraphics方法接收任何Graphics对象。”）;

}

ImageIcon icon = new ImageIcon（“back / loadingscreen.png”）;

如果（图标== NULL）{

System.out.println("The icon is not received meaning the URL path (back/laodingscreen.png) is probably wrong.");

}

Graphics.drawImage（）处的空指针异常

2 个答案: