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我想在JEditorPane的overriden DefaultStyledDocument(也提供自定義EditorKit)中插入一個LeafElement:但是我得到了一個javax.swing.text.StateInvariantError。 因此,遵循JGuru forum topic的指導原則,我添加了writeLock()和writeUnlock()調用,但是這次我的JEditorPane保持爲空。那麼,我應該如何重寫AbstractDocument的fireXXX()方法,以便通知文檔的所有偵聽器?自己插入LeafElement
這裏我的主類:MyFrame.java
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
public class MyFrame extends JFrame {
public MyFrame(){
setSize(400, 300);
JEditorPane editorPane = new JEditorPane();
editorPane.setEditorKit(new MyEditorKit());
add(new JScrollPane(editorPane));
}
public static void main(String[] args) {
new MyFrame().setVisible(true);
}
private static final long serialVersionUID = -2122161377842820073L;
}
這裏我班MyEditorKit.java
import javax.swing.text.Document;
import javax.swing.text.StyledEditorKit;
public class MyEditorKit extends StyledEditorKit {
@Override
public Document createDefaultDocument() {
return new MyDocument();
}
private static final long serialVersionUID = -5973765338689236766L;
}
而且我的課MyDocument.java
import javax.swing.JLabel;
import javax.swing.text.DefaultStyledDocument;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;
public class MyDocument extends DefaultStyledDocument {
public MyDocument(){
BranchElement rootElement = (BranchElement) getDefaultRootElement();
writeLock();
LeafElement black10Element = (LeafElement) createLeafElement(rootElement, new SimpleAttributeSet(),0, 1);
JLabel black10 = new JLabel("10 ...");
StyleConstants.setComponent(black10Element, black10);
writeUnlock();
}
private static final long serialVersionUID = -7424640574620960694L;
}
這是錯誤堆棧跟蹤當我用writeLock()和writeUnlock()註釋行時:
Exception in thread "main" javax.swing.text.StateInvariantError: Illegal cast to MutableAttributeSet
at javax.swing.text.AbstractDocument$AbstractElement.checkForIllegalCast(AbstractDocument.java:2050)
at javax.swing.text.AbstractDocument$AbstractElement.addAttributes(AbstractDocument.java:1983)
at javax.swing.text.AbstractDocument$AbstractElement.<init>(AbstractDocument.java:1777)
at javax.swing.text.AbstractDocument$LeafElement.<init>(AbstractDocument.java:2502)
at javax.swing.text.AbstractDocument.createLeafElement(AbstractDocument.java:1275)
at MyDocument.<init>(MyDocument.java:13)
at MyEditorKit.createDefaultDocument(MyEditorKit.java:9)
at javax.swing.JEditorPane.setEditorKit(JEditorPane.java:1058)
at MyFrame.<init>(MyFrame.java:11)
at MyFrame.main(MyFrame.java:16)
在此先感謝。