Java 缓冲区策略：编译器不喜欢它
我正在尝试在画布上使用双缓冲，这是我以前从未做过的事情。我利用了在线教程，并设置了以下代码来实例化画布并为其设置缓冲。我编写了完整的过程，包括渲染图形（此处未显示），并且编译器接受它。
volCanvas = new VolCanvas();
volCanvas.setBackground(Color.black);
volCanvas.setBounds(10, 380, 1180, 125);
add(volCanvas);
volCanvas.createBufferStrategy(2); (Program blows up here)
offScreen = volCanvas.getBufferStrategy();
ofsg = (Graphics2D) offScreen.getDrawGraphics();
但程序在下面代码中的标记行处崩溃了。运行时抛出非法状态异常，并解释“组件必须有一个有效的对等点”。
据我所知，源代码基本上与我在几个示例中看到的一样，所以我不知道这里发生了什么。任何帮助将不胜感激。
谢谢，
约翰·多纳
I am attempting to use double buffering with a canvas, something I've never done before. I took advantage of the tutorials online, and set up the following code to instantiate a canvas and set up the buffering for it. I coded the complete process including the rendering graphiocs (not shown here), and the compiler accepts it.
volCanvas = new VolCanvas();
volCanvas.setBackground(Color.black);
volCanvas.setBounds(10, 380, 1180, 125);
add(volCanvas);
volCanvas.createBufferStrategy(2); (Program blows up here)
offScreen = volCanvas.getBufferStrategy();
ofsg = (Graphics2D) offScreen.getDrawGraphics();
But the program blows up at the flagged line in the code below. The runtime throws an illegal state exception, with the explanation "Component must have a valid peer".
So far as I can tell, the source code is essentially as I've seen it in several examples, so I haven't a clue what is going on here. Any help would be greatly appreciated.
Thanks,
John Doner
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这基本上意味着您的 GUI 不可见，或者您尚未将组件添加到可见的 GUI。
您在论坛上的其他问题涉及 Swing 应用程序。您不应该使用 AWT 组件（Canvas）在 Swing 应用程序中，在 JComponent 或 JPanel 上进行自定义绘制默认情况下是双缓冲的。
It basically means your GUI is not visible or you haven't added your component to a visible GUI.
Your other questions on the forum deal with Swing applications. You should not use an AWT component (Canvas) in a Swing application. Do custom painting on a JComponent or JPanel. Swing is double buffered by default.