Qt的语法高亮类（注释方式）

  1 //语法高亮---QSyntaxHighlighter
  2 //highlighter.h
  3 class Highlighter : public QSyntaxHighlighter    //定义一个类继承自QSyntaxHightliaghter
  4 {
  5     Q_OBJECT                                         //Qt宏定义，使用Qt元编程
  6
  7 public:
  8     Highlighter(QTextDocument *parent = 0);      //构造函数，传递一个QTextDocument对象给其父类
  9
 10 protected:
 11     void highlightBlock(const QString &text) Q_DECL_OVERRIDE;    //块高亮使用的函数，自动调用
 12
 13 private:
 14     struct HighlightingRule                    //语法规则结构体，包含正则表达式模式串和匹配的样式
 15     {
 16         QRegExp pattern;
 17         QTextCharFormat format;
 18     };
 19     QVector<HighlightingRule> highlightingRules;    //规则的集合，可以定义多个高亮规则
 20
 21     QRegExp commentStartExpression;                //注释的高亮，使用highliangBlock()匹配，下文提到
 22     QRegExp commentEndExpression;
 23
 24     QTextCharFormat keywordFormat;                //高亮样式，关键词，一下顾名思义
 25     QTextCharFormat classFormat;
 26     QTextCharFormat singleLineCommentFormat;
 27     QTextCharFormat multiLineCommentFormat;
 28     QTextCharFormat quotationFormat;
 29     QTextCharFormat functionFormat;
 30 };
 31
 32 //highlighter.c
 33 #include "highlighter.h"
 34
 35 Highlighter::Highlighter(QTextDocument *parent)    //构造函数，主要是对词语的高亮
 36     : QSyntaxHighlighter(parent)
 37 {
 38     HighlightingRule rule;                            //高亮规则
 39
 40     keywordFormat.setForeground(Qt::darkBlue);    //设定关键词的高亮样式
 41     keywordFormat.setFontWeight(QFont::Bold);
 42     QStringList keywordPatterns;                    //关键词集合,关键都以正则表达式表示
 43     keywordPatterns << "\\bchar\\b" << "\\bclass\\b" << "\\bconst\\b"
 44                     << "\\bdouble\\b" << "\\benum\\b" << "\\bexplicit\\b"
 45                     << "\\bfriend\\b" << "\\binline\\b" << "\\bint\\b"
 46                     << "\\blong\\b" << "\\bnamespace\\b" << "\\boperator\\b"
 47                     << "\\bprivate\\b" << "\\bprotected\\b" << "\\bpublic\\b"
 48                     << "\\bshort\\b" << "\\bsignals\\b" << "\\bsigned\\b"
 49                     << "\\bslots\\b" << "\\bstatic\\b" << "\\bstruct\\b"
 50                     << "\\btemplate\\b" << "\\btypedef\\b" << "\\btypename\\b"
 51                     << "\\bunion\\b" << "\\bunsigned\\b" << "\\bvirtual\\b"
 52                     << "\\bvoid\\b" << "\\bvolatile\\b";
 53     foreach (const QString &pattern, keywordPatterns) {    //添加各个关键词到高亮规则中
 54         rule.pattern = QRegExp(pattern);
 55         rule.format = keywordFormat;
 56         highlightingRules.append(rule);
 57     }
 58
 59     classFormat.setFontWeight(QFont::Bold);        //添加Qt的类到高亮规则中
 60     classFormat.setForeground(Qt::darkMagenta);
 61     rule.pattern = QRegExp("\\bQ[A-Za-z]+\\b");
 62     rule.format = classFormat;
 63     highlightingRules.append(rule);
 64
 65     singleLineCommentFormat.setForeground(Qt::red);    //单行注释
 66     rule.pattern = QRegExp("//[^\n]*");
 67     rule.format = singleLineCommentFormat;
 68     highlightingRules.append(rule);
 69
 70     multiLineCommentFormat.setForeground(Qt::red);    //多行注释，只设定了样式，具体匹配在highlightBlock中设置
 71
 72
 73     quotationFormat.setForeground(Qt::darkGreen);    //字符串
 74     rule.pattern = QRegExp("\".*\"");
 75     rule.format = quotationFormat;
 76     highlightingRules.append(rule);
 77
 78
 79     functionFormat.setFontItalic(true);        //函数
 80     functionFormat.setForeground(Qt::blue);
 81     rule.pattern = QRegExp("\\b[A-Za-z0-9_]+(?=\\()");
 82     rule.format = functionFormat;
 83     highlightingRules.append(rule);
 84
 85
 86     commentStartExpression = QRegExp("/\\*");        //多行注释的匹配正则表达式
 87     commentEndExpression = QRegExp("\\*/");
 88 }
 89
 90
 91 void Highlighter::highlightBlock(const QString &text)    //应用高亮规则，也用于区块的高亮，比如多行注释
 92 {
 93     foreach (const HighlightingRule &rule, highlightingRules) {    //文本采用高亮规则
 94         QRegExp expression(rule.pattern);
 95         int index = expression.indexIn(text);
 96         while (index >= 0) {
 97             int length = expression.matchedLength();
 98             setFormat(index, length, rule.format);
 99             index = expression.indexIn(text, index + length);
100         }
101     }
102
103     setCurrentBlockState(0);        //以下是多行注释的匹配
104
105     int startIndex = 0;
106     if (previousBlockState() != 1)
107         startIndex = commentStartExpression.indexIn(text);
108
109     while (startIndex >= 0) {
110         int endIndex = commentEndExpression.indexIn(text, startIndex);
111         int commentLength;
112         if (endIndex == -1) {
113             setCurrentBlockState(1);
114             commentLength = text.length() - startIndex;
115         } else {
116             commentLength = endIndex - startIndex
117                             + commentEndExpression.matchedLength();
118         }
119         setFormat(startIndex, commentLength, multiLineCommentFormat);
120         startIndex = commentStartExpression.indexIn(text, startIndex + commentLength);
121     }
122 }
123 //used in editor
124 void MainWindow::setupEditor()
125 {
126     QFont font;
127     font.setFamily("Courier");
128     font.setFixedPitch(true);
129     font.setPointSize(10);
130
131     editor = new QTextEdit;
132     editor->setFont(font);
133
134     highlighter = new Highlighter(editor->document());   //调用方法，新建对象并传递document
135
136     QFile file("mainwindow.h");
137     if (file.open(QFile::ReadOnly | QFile::Text))
138         editor->setPlainText(file.readAll());
139 }

效果：