0

当我在 Linux 平台上运行我的应用程序时，它会抛出异常，并且在框架/面板中看不到任何组件，而是显示灰色屏幕，当我们单击/移动鼠标点到组件上方时，将显示该组件。我也有动态测试更新按钮，每次鼠标移动到按钮上方都会更新。

注意：这个相同的应用程序在 Windows 平台上运行良好。

INFO   | jvm 1    | main    | 2013/01/21 15:14:23.995 | Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.995 |     at javax.swing.plaf.basic.BasicButtonUI.getMinimumSize(BasicButtonUI.java:352)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.995 |     at javax.swing.JComponent.getMinimumSize(JComponent.java:1714)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.995 |     at java.awt.BorderLayout.minimumLayoutSize(BorderLayout.java:651)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.995 |     at java.awt.Container.minimumSize(Container.java:1651)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.995 |     at java.awt.Container.getMinimumSize(Container.java:1636)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at javax.swing.JComponent.getMinimumSize(JComponent.java:1716)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.FlowLayout.minimumLayoutSize(FlowLayout.java:448)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.Container.minimumSize(Container.java:1651)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.Container.getMinimumSize(Container.java:1636)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at javax.swing.JComponent.getMinimumSize(JComponent.java:1716)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.GridBagLayout.GetLayoutInfo(GridBagLayout.java:1094)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.GridBagLayout.getLayoutInfo(GridBagLayout.java:893)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.GridBagLayout.ArrangeGrid(GridBagLayout.java:2052)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.GridBagLayout.arrangeGrid(GridBagLayout.java:2008)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.GridBagLayout.layoutContainer(GridBagLayout.java:789)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.Container.layout(Container.java:1421)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.Container.doLayout(Container.java:1410)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.Container.validateTree(Container.java:1507)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.Container.validateTree(Container.java:1513)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.Container.validateTree(Container.java:1513)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.Container.validateTree(Container.java:1513)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.Container.validateTree(Container.java:1513)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.Container.validate(Container.java:1480)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at javax.swing.RepaintManager.validateInvalidComponents(RepaintManager.java:669)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:124)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:642)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventQueue.access$000(EventQueue.java:85)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventQueue$1.run(EventQueue.java:603)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventQueue$1.run(EventQueue.java:601)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.security.AccessController.doPrivileged(Native Method)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventQueue.dispatchEvent(EventQueue.java:612)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
INFO   | jvm 1    | main    | 2013/01/21 15:14:23.996 |     at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
4

1 回答 1

0

好的，让我们研究一下你的堆栈跟踪：

在 javax.swing.plaf.basic.BasicButtonUI.getMinimumSize(BasicButtonUI.java:352)

让我们看一下那里的代码：

public Dimension getMinimumSize(JComponent c) {
    Dimension d = getPreferredSize(c);
View v = (View) c.getClientProperty(BasicHTML.propertyKey);
if (v != null) {
    d.width -= v.getPreferredSpan(View.X_AXIS) - v.getMinimumSpan(View.X_AXIS); // Line 352
}
return d;
}

好的，所以你NullPointerException来自getPreferredSize(JComponent c)哪个返回null。

所以最后，要么你的按钮包含额外的组件，要么在 Linux 上选择的外观返回一个null值（无论出于何种原因，用这么少的细节几乎不可能找到）。

于 2013-01-21T16:09:04.833 回答