java更改DocumentListener中的文档 [英] java change the document in DocumentListener

问题描述

我使用 DocumentListener 来处理 JTextPane 文档中的任何更改。而用户类型我想删除 JTextPane 的内容，而是插入自定义文本。无法在 DocumentListener 中更改文档，而是在此处说出一个解决方案：
java.lang.IllegalStateException在TextArea，Java中使用Document Listener
，但我不知道我明白，至少我不知道该怎么办？

I use a DocumentListener to handle any change in a JTextPane document. while the user types i want to delete the contents of JTextPane and insert a customized text instead. it is not possible to change the document in the DocumentListener,instead a solution is said here: java.lang.IllegalStateException while using Document Listener in TextArea, Java ,but i don't understand that, at least i don't know what to do in my case?

推荐答案

DocumentListener 实际上只适用于更改通知，不应该用于修改文本字段/文档。

DocumentListener is really only good for notification of changes and should never be used to modify a text field/document.

相反，使用 DocumentFilter

Instead, use a DocumentFilter

查看此处了解示例

仅供参考

问题的根本课程是 DocumentListener 在文档更新时通知>。尝试修改文档（除了冒无限循环的风险）使文档处于无效状态，因此异常

The root course of your problem is that the DocumentListener is notified WHILE the document is been updated. Attempts to modify the document (apart from risking a infinite loop) put the document into a invalid state, hence the exception

更新示例

这是非常基本的例子......它不处理插入或删除，但是我的测试已经删除了工作而没有做任何事情......

This is VERY basic example...It doesn't handle insert or remove, but my testing had remove working without doing anything anyway...

public class TestHighlight {

    public static void main(String[] args) {
        new TestHighlight();
    }

    public TestHighlight() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JTextPane textPane = new JTextPane(new DefaultStyledDocument());
                ((AbstractDocument) textPane.getDocument()).setDocumentFilter(new HighlightDocumentFilter(textPane));
                JFrame frame = new JFrame("Test");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new JScrollPane(textPane));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }

        });
    }

    public class HighlightDocumentFilter extends DocumentFilter {

        private DefaultHighlightPainter highlightPainter = new DefaultHighlightPainter(Color.YELLOW);
        private JTextPane textPane;
        private SimpleAttributeSet background;

        public HighlightDocumentFilter(JTextPane textPane) {
            this.textPane = textPane;
            background = new SimpleAttributeSet();
            StyleConstants.setBackground(background, Color.RED);
        }

        @Override
        public void insertString(FilterBypass fb, int offset, String text, AttributeSet attr) throws BadLocationException {
            System.out.println("insert");
            super.insertString(fb, offset, text, attr);
        }

        @Override
        public void remove(FilterBypass fb, int offset, int length) throws BadLocationException {
            System.out.println("remove");
            super.remove(fb, offset, length);
        }

        @Override
        public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {

            String match = "test";

            super.replace(fb, offset, length, text, attrs);

            int startIndex = offset - match.length();
            if (startIndex >= 0) {

                String last = fb.getDocument().getText(startIndex, match.length()).trim();
                System.out.println(last);
                if (last.equalsIgnoreCase(match)) {

                    textPane.getHighlighter().addHighlight(startIndex, startIndex + match.length(), highlightPainter);

                }

            }
        }

    }

}

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