在運行時更改 Java Swing 主題會導致 JTable 錯誤

Question

我想在我的Java Swing GUI 中更改運行時的外觀和感覺。

為此，我調用UIManager.setLookAndFeel()和SwingUtilities.updateComponentTreeUI()來刷新 GUI，這似乎可以工作，但后一種方法會導致嚴重的 GUI 錯誤：任何帶有JTable的選項卡都會導致以下異常並且無法呈現適當地：

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at com.sun.java.swing.plaf.windows.WindowsTableHeaderUI$XPDefaultRenderer.paint(WindowsTableHeaderUI.java:171)
    at javax.swing.CellRendererPane.paintComponent(CellRendererPane.java:151)
    at javax.swing.plaf.basic.BasicTableHeaderUI.paintCell(BasicTableHeaderUI.java:710)
    at javax.swing.plaf.basic.BasicTableHeaderUI.paint(BasicTableHeaderUI.java:652)
    at javax.swing.plaf.synth.SynthTableHeaderUI.paint(SynthTableHeaderUI.java:173)
    at javax.swing.plaf.synth.SynthTableHeaderUI.update(SynthTableHeaderUI.java:144)
    at javax.swing.JComponent.paintComponent(JComponent.java:780)
    at javax.swing.JComponent.paint(JComponent.java:1056)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JViewport.paint(JViewport.java:728)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JLayeredPane.paint(JLayeredPane.java:586)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5217)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1579)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1502)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1272)
    at javax.swing.JComponent.paint(JComponent.java:1042)
    at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:39)
    at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:79)
    at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:116)
    at java.awt.Container.paint(Container.java:1978)
    at java.awt.Window.paint(Window.java:3906)
    at javax.swing.RepaintManager$4.run(RepaintManager.java:842)
    at javax.swing.RepaintManager$4.run(RepaintManager.java:814)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:814)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:789)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:738)
    at javax.swing.RepaintManager.access$1200(RepaintManager.java:64)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1732)
    at java.awt.event.InvocationEvent.dispatch$$$capture(InvocationEvent.java:311)

只有當鼠標移到項目上並且它不可用時，它才會呈現渲染項目的“重影”效果。

此處已報告了一個 Java 錯誤。 我正在運行 Java 版本1.8.0_231 。 有沒有辦法解決這個問題，或者我做錯了什么？

private static void setHeaderAlignment(JTable table)
{
    JTableHeader header = table.getTableHeader();
    HeaderRenderer headerRenderer = new HeaderRenderer(table);
    header.setDefaultRenderer(headerRenderer);
}

Answer 1

可能是因為您的JTableHeader header是您的 static 方法的局部變量。

嘗試將其提取為 class 中的 class 屬性，並在某個時間將其設置為 JTable。 然后調用您的 static 方法。

在嘗試設置自己的默認渲染器之前，它將提供對該屬性的訪問。

Answer 2

不設置默認渲染器可修復該錯誤。 似乎我根本不需要 header 渲染器，所以我很高興完全放棄它。