qt的高亮显示主要是使用qsyntaxhighlighter类,由于qsyntaxhighlighter是抽象基类,所以需要继承并自己实现

//头文件

#ifndef MARKDOWN_HIGHLIGHTER_H

#define MARKDOWN_HIGHLIGHTER_H

#include <QSyntaxHighlighter>

#include <qtextedit.h>

#include <qtextdocument.h>

#include <QTextCharFormat>

#include <qtextcursor.h>

#include <qhash.h>

#include <qvector.h>

#include <qregexp.h>

#include <qcolor.h>

#include <qstring.h>

class markdown_highlighter : public QSyntaxHighlighter

{

public:

    markdown_highlighter(QTextEdit *parent = 0);

    void highlightBlock(const QString &text);

    void SetColorText(const QString &str, const QColor &color);

    void clearRules();

private:

     struct HighlightingRule

      {

          QRegExp pattern;

          QTextCharFormat format;

      };

      QVector<HighlightingRule> highlightingRules;

};

#endif // MARKDOWN_HIGHLIGHTER_H

//cpp文件

#include "markdown_highlighter.h"

markdown_highlighter::markdown_highlighter(QTextEdit *parent)

    : QSyntaxHighlighter(parent)

{

    highlightingRules.clear();

}

void markdown_highlighter::highlightBlock(const QString &text)

{

    foreach (HighlightingRule rule, highlightingRules)

    {

        QRegExp expression(rule.pattern);

        int index = text.indexOf(expression);

        while (index >= 0)

        {

            int length = expression.matchedLength();

            setFormat(index, length, rule.format);

            index = text.indexOf(expression, index + length);

        }

    }

}

void markdown_highlighter::SetColorText(const QString &str, const QColor &color)

{

    HighlightingRule rule;

    rule.pattern = QRegExp(str);

    QTextCharFormat format;

    format.setForeground(color);

    rule.format = format;

    highlightingRules.append(rule);

}

void markdown_highlighter::clearRules()

{

    highlightingRules.clear();

}

然后在你需要高亮的地方即可

    md_high = new markdown_highlighter(ui->textEdit);

    md_high->SetColorText("##",Qt::green);

qt关键字高亮