jcombobox作为单元格编辑器java.awt.IllegalComponentStateException:必须在屏幕上显示组件以确定其位置

Question

我使用自定义JComboBox作为JTable中的单元格编辑器.当用户使用键盘控件进入单元格时,它会尝试打开弹出窗口.这会导致以下错误:

java.awt.IllegalComponentStateException: component must be showing on the screen to determine its location
    at java.awt.Component.getLocationOnScreen_NoTreeLock(Component.java:1964)
    at java.awt.Component.getLocationOnScreen(Component.java:1938)
    at javax.swing.JPopupMenu.show(JPopupMenu.java:887)
    at javax.swing.plaf.basic.BasicComboPopup.show(BasicComboPopup.java:191)
    at javax.swing.plaf.basic.BasicComboBoxUI.setPopupVisible(BasicComboBoxUI.java:859)
    at javax.swing.JComboBox.setPopupVisible(JComboBox.java:796)

我看过一些文章说这是一个已知问题,解决方法是设置:

    comboBox.putClientProperty("JComboBox.isTableCellEditor", Boolean.TRUE);

但这并没有帮助.无论如何这应该做什么？

我读过的关于这个的所有主题和文章对于问题的本质都非常模糊.

有没有人对这个问题出现的原因有什么了解？我的组合框是非常自定义的,所以它有助于理解问题的基础,所以我可以修复代码.

这是在捕获的组合框上的焦点获取事件上触发并调用setPopupVisible(true);

 public void focusGained(java.awt.event.FocusEvent e)
 {
        //if focus is gained then make sure we show the popup if it is suppose to be visible
            setPopupVisible(true);
        //and highlight the selected text if any
        comboTextEditor.setCaretPosition(comboTextEditor.getText().length());
        comboTextEditor.moveCaretPosition(0);
 }

顺便说一句,我在Java 1.7_40中获得与Java 1.6_45相同的结果

完整堆栈跟踪:

Exception in thread "AWT-EventQueue-1" java.awt.IllegalComponentStateException: component must be showing on the screen to determine its location
    at java.awt.Component.getLocationOnScreen_NoTreeLock(Component.java:1964)
    at java.awt.Component.getLocationOnScreen(Component.java:1938)
    at javax.swing.JPopupMenu.show(JPopupMenu.java:887)
    at javax.swing.plaf.basic.BasicComboPopup.show(BasicComboPopup.java:191)
    at javax.swing.plaf.basic.BasicComboBoxUI.setPopupVisible(BasicComboBoxUI.java:859)
    at javax.swing.JComboBox.setPopupVisible(JComboBox.java:796)
    at com.mbs.generic.view.swing.combobox.AutoCompleteComboBox$1.focusGained(AutoCompleteComboBox.java:185)
    at java.awt.AWTEventMulticaster.focusGained(AWTEventMulticaster.java:203)
    at java.awt.Component.processFocusEvent(Component.java:6179)
    at java.awt.Component.processEvent(Component.java:6046)
    at java.awt.Container.processEvent(Container.java:2039)
    at java.awt.Component.dispatchEventImpl(Component.java:4653)
    at java.awt.Container.dispatchEventImpl(Container.java:2097)
    at java.awt.Component.dispatchEvent(Component.java:4481)
    at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1848)
    at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:901)
    at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:513)
    at java.awt.Component.dispatchEventImpl(Component.java:4525)
    at java.awt.Container.dispatchEventImpl(Container.java:2097)
    at java.awt.Component.dispatchEvent(Component.java:4481)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:648)
    at java.awt.EventQueue.access$000(EventQueue.java:84)
    at java.awt.EventQueue$1.run(EventQueue.java:607)
    at java.awt.EventQueue$1.run(EventQueue.java:605)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
    at java.awt.EventQueue$2.run(EventQueue.java:621)
    at java.awt.EventQueue$2.run(EventQueue.java:619)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:618)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

谢谢

Answer 1

首先,让我解释一下comboBox.putClientProperty("JComboBox.isTableCellEditor", Boolean.TRUE);.通常,将鼠标悬停在某个项目上或按下键盘上的箭头键将导致JComboBox立即选择项目.由于来自的选择事件JComboBox将导致单元格编辑过程停止,因此此行为不适用于表格单元格.因此,当设置此特殊客户端属性项时,将在弹出列表中显示选中但尚未设置JComboBox.只有提交的项目(通过单击或Enter键)将更改所选项目,然后JComboBox导致编辑结束.至少,这适用于BasicLookAndFeel及其衍生物.

你遇到的问题完全不同.由于异常消息和堆栈跟踪清楚地说明,外观尝试打开JPopupMenu与之关联的JComboBox(如您所请求的),但它无法确定弹出菜单的屏幕位置,因为您JComboBox的镜头未显示在屏幕上屏幕.它想要位置的原因JComboBox是它打开相对于的新窗口JComboBox.

剩下的问题是为什么你收到了focusGained一个JComboBox没有在屏幕上显示的内容(或者为什么你认为你这样做).