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我试图通过覆盖我的 JPanel 的更新方法来实现我的游戏在 Java 中的双缓冲，我做了所有常用的代码等，但它仍然无法工作，它会引发堆栈溢出错误，以下是具体错误：

Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
        at java.awt.Rectangle.<init>(Rectangle.java:193)
        at java.awt.Rectangle.<init>(Rectangle.java:208)
        at sun.awt.image.BufImgSurfaceData.getBounds(BufImgSurfaceData.java:369)
        at sun.java2d.loops.GraphicsPrimitive.convertFrom(GraphicsPrimitive.java:533)
        at sun.java2d.loops.GraphicsPrimitive.convertFrom(GraphicsPrimitive.java:523)
        at sun.java2d.loops.MaskBlit$General.MaskBlit(MaskBlit.java:171)
        at sun.java2d.loops.Blit$GeneralMaskBlit.Blit(Blit.java:186)
        at sun.java2d.pipe.DrawImage.blitSurfaceData(DrawImage.java:927)
        at sun.java2d.pipe.DrawImage.renderImageCopy(DrawImage.java:550)
        at sun.java2d.pipe.DrawImage.copyImage(DrawImage.java:54)
        at sun.java2d.pipe.DrawImage.copyImage(DrawImage.java:982)
        at sun.java2d.SunGraphics2D.drawImage(SunGraphics2D.java:2979)
        at sun.java2d.SunGraphics2D.drawImage(SunGraphics2D.java:2964)
        at epicgame.Menu.displayMenu(Menu.java:71)
        at epicgame.GUI$1.paintComponent(GUI.java:64)
        at javax.swing.JComponent.paint(JComponent.java:1029)
        at epicgame.GUI$1.update(GUI.java:117)
        at epicgame.GUI$1.paintComponent(GUI.java:98)
        at javax.swing.JComponent.paint(JComponent.java:1029)

我的代码也不是特别复杂：

mainPanel = new JPanel()
        {
            @Override protected void paintComponent(Graphics g)
            {
                //super.paintComponent(g);

                if(menuEnabled == 1)
                {
                    Menu.displayMenu(g, mainPanel);
                }
                else if(gameNum == 1)
                { 
                    StreetFighter.StreetFighter(g, mainPanel);

                    // Calls the controls method within the controls class.
                    Controls.controls(Calendar.getInstance().getTimeInMillis() - timeOld);
                    timeOld = Calendar.getInstance().getTimeInMillis();
                }
                else if(gameNum == -1)
                {
                    Menu.scoreBoard(g, mainPanel);
                    if(loaded != true)
                    {
                        Menu.loadScoreBoard(mainPanel);
                        loaded = true;
                    }
                }
                if(gameNum > 0)
                {
                    if(longcat == true && longcatloaded != true)
                    {
                        Extras.loadLongCat();
                        longcatloaded = true;
                    }
                    if(longcatloaded == true && longcat == true)
                    {
                        Extras.displayLongCat(g, mainPanel);
                    }
                }

                // Causes an infinite loop, e.g makes the screen render over and over.
                //repaint();
                update(g);
            }

            @Override public void update(Graphics g)
            {
                System.err.println("Updating screen and using double buffer!");

                // initialize buffer
                if(dbImage == null)
                {
                    dbImage = createImage (this.getSize().width, this.getSize().height);
                    dbg = dbImage.getGraphics ();
                }
                // clear screen in background
                dbg.setColor (getBackground ());
                dbg.fillRect (0, 0, this.getSize().width, this.getSize().height);
                // draw elements in background
                dbg.setColor (getForeground());

                paint(dbg);

                // draw image on the screen
                g.drawImage (dbImage, 0, 0, this);

                try
                {
                    Thread.sleep(200);

                }
                catch (InterruptedException ex)
                {
                    System.err.print("cant delay repaint.");
                }
            }
        };

我希望有人能指出我哪里出错了，我在想可能与更新被调用太多次有关，或者可能更新是错误的方法？

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3 回答 3

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不要从. paint()_update()paintComponent()

也不要调用Thread.sleep()任何绘画方法。相反，创建一个线程，每 x 毫秒更新一次游戏模型，然后调用repaint()您已覆盖的自定义组件，paintComponent()以便绘制游戏状态。

于 2011-03-19T03:07:02.843 回答
1

您在paint组件内部调用paintComponent，这将导致组件不断重新绘制自身。这将导致StackOverflowException. 此外，API会告诫开发人员paint在应用程序中显式调用：

由 Swing 调用以绘制组件。应用程序不应直接调用paint，而应使用repaint 方法来安排组件重绘。

该方法实际上将绘画工作委托给了三个受保护的方法：paintComponent、paintBorder 和paintChildren。它们按列出的顺序调用，以确保子组件出现在组件本身的顶部。一般来说，组件及其子组件不应该在分配给边框的 insets 区域中进行绘制。子类可以像往常一样覆盖这个方法。只想专门化 UI（外观和感觉）委托的绘制方法的子类应该重写paintComponent。

于 2011-03-19T03:13:20.453 回答
0

您需要在g.dispose()完成后调用每一帧，否则它将永远不会从内存中释放，并且您会看到堆栈溢出错误。 http://download.oracle.com/javase/1.3/docs/api/java/awt/Graphics.html

于 2011-03-19T03:03:26.487 回答