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[英]Java exception: java.lang.ClassCastException: javax.swing.Timer cannot be cast to javax.swing.JButton
[英]How to resolve this error “java.lang.ClassCastException: javax.swing.JList$3 cannot be cast to javax.swing.DefaultListModel”
我从下拉列表中获取选定的值并添加到 jlist 中。 但是我只收到我的字段(日期选择器字段和另一个组合框字段)的这个错误。 我初始化并使用了默认列表模型。 每次在添加之前我都会清除我的清单。 但是当我在组合框中选择一个值时,它显示错误为
4 Mar, 2014 7:39:23 AM adminscreen.taskallocationscreennew t_dateActionPerformed
SEVERE: null
java.lang.ClassCastException: javax.swing.JList$3 cannot be cast to javax.swing.DefaultListModel
at adminscreen.taskallocationscreennew.t_dateActionPerformed(taskallocationscreennew.java:820)
at adminscreen.taskallocationscreennew.access$600(taskallocationscreennew.java:50)
at adminscreen.taskallocationscreennew$7.actionPerformed(taskallocationscreennew.java:579)
at org.jdesktop.swingx.JXDatePicker.fireActionPerformed(JXDatePicker.java:876)
at org.jdesktop.swingx.JXDatePicker.commitEdit(JXDatePicker.java:706)
at org.jdesktop.swingx.plaf.basic.BasicDatePickerUI.commit(BasicDatePickerUI.java:901)
at org.jdesktop.swingx.plaf.basic.BasicDatePickerUI$Handler.monthViewActionPerformed(BasicDatePickerUI.java:1374)
at org.jdesktop.swingx.plaf.basic.BasicDatePickerUI$Handler.actionPerformed(BasicDatePickerUI.java:1349)
at org.jdesktop.swingx.JXMonthView.fireActionPerformed(JXMonthView.java:1797)
at org.jdesktop.swingx.JXMonthView.commitSelection(JXMonthView.java:1695)
at org.jdesktop.swingx.plaf.basic.BasicMonthViewUI$Handler.mouseReleased(BasicMonthViewUI.java:2075)
at java.awt.Component.processMouseEvent(Component.java:6267)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
at java.awt.Component.processEvent(Component.java:6032)
at java.awt.Container.processEvent(Container.java:2041)
at java.awt.Component.dispatchEventImpl(Component.java:4630)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4577)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
at java.awt.Container.dispatchEventImpl(Container.java:2085)
at java.awt.Window.dispatchEventImpl(Window.java:2478)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
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)
下面是我的代码:
private void d_pagetypeActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
System.out.println("d_pagetype"+d_pagetype.getSelectedItem());
try {
if(l_storieslist.getModel() != null)
{
((DefaultListModel) l_storieslist.getModel()).clear();
listf(directoryName);
}
else
{
}
} catch (Exception ex) {
Logger.getLogger(taskallocationscreennew.class.getName()).log(Level.SEVERE, null, ex);
}
l_storieslist.setModel(fileNameList);
l_storieslist.setBackground(Color.WHITE);
}
在以下行中:
l_storieslist.setModel(fileNameList);
fileNameList 是 JList 的实例,它应该是 DefaultListModel 的实例。
可能您不需要再次设置模型。 而是在现有模型上进行操作。 您可以像在代码中一样获取对现有模型的引用
ListModel model = l_storieslist.getModel();
并执行添加/删除您想要的任何列表项的操作。
模型应该在 List 初始化时设置( 在这里发现)
默认情况下,它使用内部类 impl 作为模型,您需要在构建列表时显式设置 DefaultListModel!
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