pyqt SyntaxHighlighter 怎么使用

PyQt中的`QSyntaxHighlighter`类可以用于在`QPlainTextEdit`或`QTextEdit`中高亮显示文本。下面是一个简单的示例：

from PyQt5.QtCore import QRegExp
from PyQt5.QtGui import QColor, QTextCharFormat, QFont, QSyntaxHighlighter
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QTextEdit
import sys

class PythonHighlighter(QSyntaxHighlighter):
    def __init__(self, parent=None):
        super(PythonHighlighter, self).__init__(parent)
        keywordFormat = QTextCharFormat()
        keywordFormat.setForeground(QColor(200, 111, 0))
        keywordFormat.setFontWeight(QFont.Bold)
        keywords = ["False", "None", "True", "and", "as", "assert", "async",
                    "await", "break", "class", "continue", "def", "del", "elif",
                    "else", "except", "finally", "for", "from", "global", "if",
                    "import", "in", "is", "lambda", "nonlocal", "not", "or",
                    "pass", "raise", "return", "try", "while", "with", "yield"]
        self.highlightingRules = [(QRegExp("\\b" + keyword + "\\b"), keywordFormat)
                                  for keyword in keywords]
        self.numberFormat = QTextCharFormat()
        self.numberFormat.setForeground(QColor(255, 0, 0))
        self.highlightingRules.append((QRegExp("\\b[0-9]+\\b"), self.numberFormat))
        self.stringFormat = QTextCharFormat()
        self.stringFormat.setForeground(QColor(0, 128, 0))
        self.highlightingRules.append((QRegExp("\".*\""), self.stringFormat))
        self.highlightingRules.append((QRegExp("\'.*\'"), self.stringFormat))

    def highlightBlock(self, text):
        for pattern, format in self.highlightingRules:
            expression = QRegExp(pattern)
            index = expression.indexIn(text)
            while index >= 0:
                length = expression.matchedLength()
                self.setFormat(index, length, format)
                index = expression.indexIn(text, index + length)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = QWidget()
    layout = QVBoxLayout(window)
    editor = QTextEdit()
    layout.addWidget(editor)
    highlighter = PythonHighlighter(editor.document())
    window.show()
    sys.exit(app.exec_())

在这个例子中，我们继承了`QSyntaxHighlighter`类，并在`highlightBlock()`函数中定义了一些高亮显示规则。例如，我们使用`QRegExp`匹配关键字、数字和字符串，并使用不同的颜色和字体格式来显示它们。

在主函数中，我们创建了一个`QTextEdit`控件并将其添加到布局中。然后，我们创建了一个`PythonHighlighter`对象，并将其附加到编辑器的文档中。

运行这个例子，你将看到一个简单的文本编辑器，它可以高亮显示Python代码的关键字、数字和字符串。