XML 元素指的是從（且包括）開始標籤直到（且包括）結束標籤的部分。
屬性通常提供不屬於數據組成部分的信息。
命名空間，使用前綴來避免命名衝突
<h:table>
<h:tr>
<h:td>Apples</h:td>
<h:td>Bananas</h:td>
</h:tr>
</h:table>
XML Namespace (xmlns) 屬性
XML 命名空間屬性被放置於元素的開始標籤之中，並使用以下的語法：
xmlns:namespace-prefix=“namespaceURI”
xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”，
告知XML解析器根據某個 schema 來驗證此文檔
XSD （xml Schema Definition）
[signal] void QTreeWidget::itemActivated(QTreeWidgetItem *item, int column)
This signal is emitted when the user activates an item by single- or double-clicking (depending on the platform, i.e. on the QStyle::SH_ItemView_ActivateItemOnSingleClick style hint) or pressing a special key (e.g., Enter).
void QXmlStreamReader::setDevice(QIODevice *device)
Sets the current device to device. Setting the device resets the stream to its initial state.
QXmlStreamReader::TokenType QXmlStreamReader::readNext()
Reads the next token and returns its type.
bool QXmlStreamReader::atEnd() const
Returns true if the reader has read until the end of the XML document,
QStringRef QXmlStreamReader::name() const
Returns the local name of a StartElement, EndElement, or an EntityReference.
QXmlStreamAttributes QXmlStreamReader::attributes() const
Returns the attributes of a StartElement.
QStringRef QXmlStreamAttributes::value(const QString &namespaceUri, const QString &name) const
Returns the value of the attribute name in the namespace described with namespaceUri,
QString QXmlStreamReader::readElementText(QXmlStreamReader::ReadElementTextBehaviour behaviour = ErrorOnUnexpectedElement)
Convenience function to be called in case a StartElement was read. Reads until the corresponding EndElement and returns all
text in-between.