Qt以QXmlStreamReader 遍历.ts文件的C++代码，查找所有source为abc的字段，修改其translation字段为123，并写入保存文件

下面是代码示例：

#include <QtCore/QCoreApplication>
#include <QtCore/QFile>
#include <QtCore/QXmlStreamReader>
#include <QtCore/QXmlStreamWriter>

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

    QString fileName = "example.ts";
    QFile file(fileName);
    if (!file.open(QFile::ReadOnly | QFile::Text)) {
        qDebug() << "Failed to open file.";
        return -1;
    }

    QXmlStreamReader xmlReader(&file);
    xmlReader.setNamespaceProcessing(false);

    QFile outputFile("modified.ts");
    if (!outputFile.open(QFile::WriteOnly | QFile::Text)) {
        qDebug() << "Failed to open output file.";
        return -1;
    }

    QXmlStreamWriter xmlWriter(&outputFile);
    xmlWriter.setAutoFormatting(true);
    xmlWriter.writeStartDocument();
    xmlWriter.writeStartElement("TS");

    while (!xmlReader.atEnd()) {
        xmlReader.readNext();
        if (xmlReader.isStartElement() && xmlReader.name() == "context") {
            xmlReader.readNext();
            while (!(xmlReader.isEndElement() && xmlReader.name() == "context")) {
                if (xmlReader.isStartElement() && xmlReader.name() == "message") {
                    QString source;
                    QString translation;
                    bool found = false;
                    xmlReader.readNext();
                    while (!(xmlReader.isEndElement() && xmlReader.name() == "message")) {
                        if (xmlReader.isStartElement() && xmlReader.name() == "source") {
                            source = xmlReader.readElementText();
                        } else if (xmlReader.isStartElement() && xmlReader.name() == "translation") {
                            translation = xmlReader.readElementText();
                        }
                        if (source == "abc" && !translation.isEmpty()) {
                            found = true;
                            translation = "123";
                        }
                        xmlReader.readNext();
                    }
                    if (found) {
                        xmlWriter.writeStartElement("message");
                        xmlWriter.writeStartElement("source");
                        xmlWriter.writeCharacters(source);
                        xmlWriter.writeEndElement();
                        xmlWriter.writeStartElement("translation");
                        xmlWriter.writeCharacters(translation);
                        xmlWriter.writeEndElement();
                        xmlWriter.writeEndElement();
                    }
                }
                xmlReader.readNext();
            }
        }
    }

    xmlWriter.writeEndElement();
    xmlWriter.writeEndDocument();

    return a.exec();
}

这段代码使用 `QXmlStreamReader` 解析 `.ts` 文件，并且使用 `QXmlStreamWriter` 写入修改后的 `.ts` 文件。对于每个 `context`，它会遍历所有的 `message`，并且查找 `source` 为 `abc` 的字段，如果找到了，就将其 `translation` 字段修改为 `123` 并且写入 `.ts` 文件。注意，这个代码没有处理错误情况，实际使用时可能需要加入相关的错误处理代码。