我正在尝试创建一个非常简单的聊天窗口,它能够显示一些我不时添加的文本。但是,在尝试将文本附加到窗口时出现以下运行时错误:
java.lang.ClassCastException: javax.swing.JViewport cannot be cast to javax.swing.JTextPane
at ChatBox.getTextPane(ChatBox.java:41)
at ChatBox.getDocument(ChatBox.java:45)
at ChatBox.addMessage(ChatBox.java:50)
at ImageTest2.main(ImageTest2.java:160)
这是处理基本操作的类:
public class ChatBox extends JScrollPane {
private Style style;
public ChatBox() {
StyleContext context = new StyleContext();
StyledDocument document = new DefaultStyledDocument(context);
style = context.getStyle(StyleContext.DEFAULT_STYLE);
StyleConstants.setAlignment(style, StyleConstants.ALIGN_LEFT);
StyleConstants.setFontSize(style, 14);
StyleConstants.setSpaceAbove(style, 4);
StyleConstants.setSpaceBelow(style, 4);
JTextPane textPane = new JTextPane(document);
textPane.setEditable(false);
this.add(textPane);
}
public JTextPane getTextPane() {
return (JTextPane) this.getComponent(0);
}
public StyledDocument getDocument() {
return (StyledDocument) getTextPane().getStyledDocument();
}
public void addMessage(String speaker, String message) {
String combinedMessage = speaker + ": " + message;
StyledDocument document = getDocument();
try {
document.insertString(document.getLength(), combinedMessage, style);
} catch (BadLocationException badLocationException) {
System.err.println("Oops");
}
}
}
如果有更简单的方法可以做到这一点,请务必告诉我。我只需要文本是单一字体类型,并且用户无法编辑。除此之外,我只需要能够即时附加文本。