为什么调用JFrame.pack（）会增加额外的空间？

最初，我使用的代码运行良好，但有点令人费解。 将方法的某些部分移动到JFrame的构造函数后，事情正常。

除了使用pack（）之外的所有东西都能使框架成为合适的尺寸。

这是原始代码：

public class BaseGameFrame extends JFrame { public static final int WINDOWED = 0; public static final int UFS = 1; protected BaseGamePanel gamePanel; public BaseGameFrame(String title, int pWidth, int pHeight, long period, int windowType){ super(title); switch(windowType){ case UFS: this.setUndecorated(true); Rectangle screenSize = this.getGraphicsConfiguration().getBounds(); pWidth = screenSize.width; pHeight = screenSize.height; break; default: break; } this.setVisible(true); this.setResizable(false); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); this.createPanel(pWidth, pHeight, period); } protected void createPanel(final int pWidth, final int pHeight, long period){ this.gamePanel = new BaseGamePanel(pWidth, pHeight, period); this.add(this.gamePanel); this.pack(); } public static void main(String[] args){ new BaseGameFrame("Test", 800, 600, 20L * 1000000L, UFS); } } 

这是在修改它之后：

 public class BaseGameFrame extends JFrame { protected BaseGamePanel gamePanel; public BaseGameFrame(String title, VideoType vType, BaseGamePanel gp){ super(title); switch(vType){ case UFS: this.setUndecorated(true); Rectangle screenSize = this.getGraphicsConfiguration().getBounds(); gp.setPDimensions(new Dimension(screenSize.width, screenSize.height)); break; default: break; } this.add(gp); this.pack(); this.setVisible(true); this.setResizable(false); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } public static void main(String[] args){ BaseGamePanel gp = new BaseGamePanel(800, 600, 20L * 1000000L); new BaseGameFrame("Test", VideoType.UFS, gp); } } 

我不太确定问题是什么……但最终发生的事情是：

Answer 1

确保在调用pack()或setVisible(true) 之前调用setResizable(false) setVisible(true)