我写了一个小程序地址簿,联系人存储在xml文件中。这是代码
之外的部分void new_engine::main_window::write_to_db(const QString& n, const QString& s)
{
QFile m_db_file(m_db_path);
QString t("User");
m_db_file.open(QIODevice::Append);
QXmlStreamWriter wxml(&m_db_file);
wxml.setAutoFormatting(true);
if(m_size == 1)
{
wxml.writeStartDocument();
wxml.writeStartElement("Persons");
}
wxml.writeStartElement(t);
QString id = QString::number(m_size);
wxml.writeAttribute("id", id);
wxml.writeTextElement("Name", n);
wxml.writeTextElement("Surname", s);
wxml.writeEndElement();
wxml.writeEndDocument();
m_db_file.close();
}
,但问题是,在第一次接触的标签文件被关闭。以下是结果
<?xml version="1.0" encoding="UTF-8"?>
<Persons>
<User id="1">
<Name>das</Name>
<Surname>vcvx</Surname>
</User>
</Persons>
<User id="2">
<Name>eqwevxcv</Name>
<Surname>xcvxcx</Surname>
</User>
<User id="3">
<Name>das</Name>
<Surname>dasdasd</Surname>
</User>
但它必须如此
<Persons>
<User id="1">
<Name>das</Name>
<Surname>vcvx</Surname>
</User>
<User id="2">
<Name>eqwevxcv</Name>
<Surname>xcvxcx</Surname>
</User>
<User id="3">
<Name>das</Name>
<Surname>dasdasd</Surname>
</User>
</Persons>
我们如何做到这一点,之后每一个新的记录将不得不改变文档的结尾?
这是一个例子:
void write_to_db(QXmlStreamWriter& writer, QString id, QString name, QString surname)
{
writer.writeStartElement("User");
writer.writeAttribute(QXmlStreamAttribute("id", id));
writer.writeTextElement("Name", name);
writer.writeTextElement("Surname", surname);
writer.writeEndElement();
}
// This can be a file, or whatever iodevice your heart desires.
QString out;
QXmlStreamWriter writer(&out);
writer.writeStartDocument();
writer.writeStartElement("Persons");
write_to_db(writer, "1", "das", "vcvx");
write_to_db(writer, "2", "das", "vcvx");
write_to_db(writer, "3", "das", "vcvx");
writer.writeEndElement(); // Close <persons> tag
writer.writeEndDocument();
输出(使用QXmlStreamWriter::setAutoFormatting/缩进):
<?xml version="1.0"?>
<Persons>
<User id="1">
<Name>das</Name>
<Surname>vcvx</Surname>
</User>
<User id="2">
<Name>das</Name>
<Surname>vcvx</Surname>
</User>
<User id="3">
<Name>das</Name>
<Surname>vcvx</Surname>
</User>
</Persons>