c++ - QSyntaxHighlighter 不创建 QTextFragments

Question

我正在使用 Qt 开发语法荧光笔，我想在其上添加单元测试以检查格式是否得到了很好的应用。但我没能按格式划分块。我使用 QTextBlock 和 QTextFragment 但它在 QTextFragment 的文档时不起作用说:

A text fragment describes a piece of text that is stored with a single character format.

这是可运行的 main.cpp 文件中的代码:

#include <QApplication>
#include <QTextEdit>
#include <QSyntaxHighlighter>
#include <QRegularExpression>
#include <QDebug>

class Highlighter : public QSyntaxHighlighter
{
public:

    Highlighter(QTextDocument *parent)
        : QSyntaxHighlighter(parent)
    {}

protected:

    void highlightBlock(const QString& text) override
    {
        QTextCharFormat classFormat;
        classFormat.setFontWeight(QFont::Bold);

        QRegularExpression pattern { "\\bclass\\b" };

        QRegularExpressionMatchIterator matchIterator = pattern.globalMatch(text);
        while (matchIterator.hasNext())
        {
            QRegularExpressionMatch match = matchIterator.next();
            setFormat(match.capturedStart(), match.capturedLength(), classFormat);
        }


        // ==== TESTS ==== //

        qDebug() << "--------------------------------";
        QTextDocument *doc = document();

        QTextBlock currentBlock = doc->firstBlock();

        while (currentBlock.isValid()) {
            qDebug() << "BLOCK" << currentBlock.text();

            QTextBlockFormat blockFormat = currentBlock.blockFormat();
            QTextCharFormat charFormat = currentBlock.charFormat();
            QFont font = charFormat.font();

            // each QTextBlock holds multiple fragments of text, so iterate over it:
            QTextBlock::iterator it;
            for (it = currentBlock.begin(); !(it.atEnd()); ++it) {
                QTextFragment currentFragment = it.fragment();
                if (currentFragment.isValid()) {
                    // a text fragment also has a char format with font:
                    QTextCharFormat fragmentCharFormat = currentFragment.charFormat();
                    QFont fragmentFont = fragmentCharFormat.font();

                    qDebug() << "FRAGMENT" << currentFragment.text();
                }
            }

            currentBlock = currentBlock.next();
        }
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    auto *textEdit = new QTextEdit;
    auto *highlighter = new Highlighter(textEdit->document());
    Q_UNUSED(highlighter);

    textEdit->setText("a class for test");

    textEdit->show();

    return a.exec();
}

并且它只输出一个 block “a class for test”和一种格式“a class for test”，而 class 关键字以粗体显示。

感谢您的帮助!

Answer 1

好的，我从 QSyntaxHighlighter::setFormat 的文档中找到了这个:

Note that the document itself remains unmodified by the format set through this function.

语法高亮器应用的格式不存储在 QTextBlock::charFormat 中，而是存储在附加格式中:

QVector<QTextLayout::FormatRange> formats = textEdit->textCursor().block().layout()->formats();