Update XML file in QT

Question

I have Xml file ``` ``` in the above XML how can I update `RName` to `RN` and `CName` to `CN` using QT. I am using `QDomDocument` but not able to do required thing.

Accepted Answer

It would help if you share information how you are using QDomDocument and which part exactly is tricky. But here how it goes in general:

file is being read from a file system;

file is being parsed into QDomDocument;

content of document is being modified;

data is being saved back to the file.

In the Qt code:

```
// Open file
QDomDocument doc("mydocument");
QFile file("mydocument.xml");
if (!file.open(QIODevice::ReadOnly)) {
    qError("Cannot open the file");
    return;
}
// Parse file
if (!doc.setContent(&file)) {
   qError("Cannot parse the content");
   file.close();
   return;
}
file.close();

// Modify content
QDomNodeList roots = elementsByTagName("root");
if (roots.size() < 1) {
   qError("Cannot find root");
   return;
}
QDomElement root = roots.at(0).toElement();
root.setAttribute("rootname", "RN");
// Then do the same thing for somechild
...

// Save content back to the file
if (!file.open(QIODevice::Truncate | QIODevice::WriteOnly)) {
    qError("Basically, now we lost content of a file");
    return;
}
QByteArray xml = doc.toByteArray();
file.write(xml);
file.close();
```

Note, in real life applications you will want to save data to another file, ensure save was successful and then replace original file with a copy.

Update XML file in QT

Solution

Problem