1、DOM方式

寫xml檔案，以QDomText方式寫，程式碼如下

QFile file("d:/test.txt");
file.open(QIODevice::WriteOnly);

QDomDocument doc;
QDomProcessingInstruction instruction;

instruction = doc.createProcessingInstruction("xml", "version = \'1.0\'");
doc.appendChild(instruction);
QDomElement root = doc.createElement("html");
doc.appendChild(root);

QDomElement data;
QDomElement tmp;
QDomText text;

data = doc.createElement("title");
text = doc.createTextNode(QStringLiteral("多看"));
data.appendChild(text);
root.appendChild(data);

tmp = doc.createElement("book");
text = doc.createTextNode(QStringLiteral("小說"));
tmp.appendChild(text);
root.appendChild(tmp);


QTextStream out(&file);
doc.save(out, 4);

file.close();
 

讀程式碼為

QFile file("d:/test.txt");
file.open(QIODevice::ReadOnly);
QDomDocument doc;
doc.setContent(&file);
QDomElement root = doc.documentElement();
for (QDomNode node = root.firstChild(); !node.isNull(); node = node.nextSibling()) {
	QDomElement element = node.toElement();
	QString tagName = element.tagName();
	if (tagName == "title") {
		qDebug() << element.text();
	} else if (tagName == "book") {
		qDebug() << element.text();
	}
}
file.close();
 

以QDomAttr方式寫：

QFile file("d:/test.txt");
file.open(QIODevice::WriteOnly);

QDomDocument doc;
QDomProcessingInstruction instruction;

instruction = doc.createProcessingInstruction("xml", "version = \'1.0\'");
doc.appendChild(instruction);
QDomElement root = doc.createElement("html");
doc.appendChild(root);

QDomAttr data;
QDomAttr tmp;

data = doc.createAttribute("title");
data.setValue(QStringLiteral("多看"));
root.setAttributeNode(data);

tmp = doc.createAttribute("book");
tmp.setValue(QStringLiteral("小說"));
root.setAttributeNode(tmp);


QTextStream out(&file);
doc.save(out, 4);

file.close();
 

讀QDomAttr

QFile file("d:/test.txt");
file.open(QIODevice::ReadOnly);
QDomDocument doc;
doc.setContent(&file);
QDomElement root = doc.documentElement();

qDebug() << root.attribute("title");
qDebug() << root.attribute("book");

file.close();

寫檔案，設定相關聯的檔案，用writeStartDocument來開始，用writeEndDocument來結束

用writeStartElement和writeEndElement來表示元素的開始和結束，需要成對使用

<name>a</name>形式，用writeTextElement

<name a=""/>形式，用writeAttribute

QFile file("test.txt"); file.open(QIODevice::writeOnly);
QXmlStreamWriter xmlstreamwriter(&file);
xmlstreamwriter.setAutoFormatting(true);
xmlstreamwriter.writeStartDocument();
xmlstreamwriter.writeStartElement("xml");
xmlstreamwriter.writeStartElement("round");
xmlstreamwriter.writeAttribute("id", mRoundId);
xmlstreamwriter.writeAttribute("tableid", mTableId);
//player1
xmlstreamwriter.writeStartElement("player1");
xmlstreamwriter.writeAttribute("framescore", mPlayer1Frame);
xmlstreamwriter.writeAttribute("points", mPlayer1Point);
xmlstreamwriter.writeAttribute("break", mPlayer1ContinuePoint);
　　xmlstreamwriter.writeCharacters("Hello World");   //新增內容
xmlstreamwriter.writeEndElement();
//player2
xmlstreamwriter.writeStartElement("player2");
xmlstreamwriter.writeAttribute("framescore", mPlayer2Frame);
xmlstreamwriter.writeAttribute("points", mPlayer2Point);
xmlstreamwriter.writeAttribute("break", mPlayer2ContinuePoint);
xmlstreamwriter.writeEndElement();
xmlstreamwriter.writeEndElement();
xmlstreamwriter.writeEndElement();
xmlstreamwriter.writeEndDocument(); file.close();

<?xml version="1.0" encoding="UTF-8"?>
<xml>
    <round id="" tableid="1">
        <player1 framescore="" points="" break="">Hello World</player1>
        <player2 framescore="" points="" break=""/>
    </round>
</xml>

讀檔案時，用isStartElement來判斷標誌的起始

<name a=""></name>形式，用attributes().value("a")

<name>a</name>形式，用readElementText

在讀取時，是通過迴圈，while (!reader.atEnd()) {reader.readNext();.....;}

QFile file("test.txt");
file.open(QIODevice::ReadOnly);

QXmlStreamReader reader(&file);

while (!reader.atEnd()) {
	reader.readNext();
	if (reader.isStartElement()) {
		if (reader.name() == "round") {
			qDebug() << reader.attributes().value("id").toString();
			qDebug() << reader.attributes().value("tableid").toString();
		} else if (reader.name() == "player1") {
			qDebug() << reader.attributes().value("framescore").toString();
			qDebug() << reader.attributes().value("points").toString();
			qDebug() << reader.attributes().value("break").toString();
			qDebug() << reader.readElementText();
		} else if (reader.name() == "player2") {
			qDebug() << reader.attributes().value("framescore").toString();
			qDebug() << reader.attributes().value("points").toString();
			qDebug() << reader.attributes().value("break").toString();
			qDebug() << reader.readElementText();
		}
	}
}
file.close();

"" 
"1" 
"" 
"" 
"" 
"Hello World" 
"" 
"" 
"" 
""