QFile file("damusercam.xml");
file.open(QFile::ReadWrite | QFile::Text);
QString errorStr;
int errorLine;
int errorColumn;
QDomDocument doc;
doc.setContent(&file, false, &errorStr, &errorLine,&errorColumn);
QDomNode root = doc.documentElement();
QDomNode child = root.firstChild();
child.toElement().setAttribute("eye_0", "-800");
QTextStream out(&file);
doc.save(out, 3);
运行发现，原来
<p>
……
<viewpoint name = "p1"
eye_0 = "-822.315" eye_1 = "-595.152" eye_2= "353.516"
center_0 = "-821.513" center_1 = "-594.555" center_2 = "353.511"
up_0 = "-0.0333913" up_1 = "0.0524172" up_2 = "0.998067">
</viewpoint>
……
</p>
变成了
<p>
……
<viewpoint name = "p1"
eye_0 = "-822.315" eye_1 = "-595.152" eye_2= "353.516"
center_0 = "-821.513" center_1 = "-594.555" center_2 = "353.511"
up_0 = "-0.0333913" up_1 = "0.0524172" up_2 = "0.998067">
</viewpoint>
……
</p>
<p>
……
<viewpoint name = "p1"
eye_0 = "-800" eye_1 = "-595.152" eye_2= "353.516"
center_0 = "-821.513" center_1 = "-594.555" center_2 = "353.511"
up_0 = "-0.0333913" up_1 = "0.0524172" up_2 = "0.998067">
</viewpoint>
……
</p>
修改后的内容只是添加在原内容的尾部，怎么才能只修改原文件？
