[Solved] QXmlQuery returns null item

[johnlubest]

Hi, I'm using a code probed to work with others xquery files, but in this case my code is not working.

Here is xml file i'm using:
@<comandos>
<comando servicio="plafones" on=true id="1">2cp0021\n\r</comando>
<comando servicio="plafones" on=true id="2">2cp0023\n\r</comando>
<comando servicio="plafones" on=true id="3">2cp0025\n\r</comando>
<comando servicio="plafones" on=false id="1">2cp0022\n\r</comando>
<comando servicio="plafones" on=false id="2">2cp0024\n\r</comando>
<comando servicio="plafones" on=false id="3">2cp0026\n\r</comando>
</comandos>@

Note: true and false are between double quotes in real file, I had to delete in here because on parameter got erased in the post.

Here is xquery file:
@declare variable $inputDocument external;
declare variable $servicio external;
declare variable $on external;
declare variable $id external;

doc($inputDocument)//comandos/comando[@servicio=xs:string($servicio) and @on=xs:boolean($on) and @id=xs:integer($id)]/string()@

xmlpatterns console command returns the correct string as result:
@$ xmlpatterns -param inputDocument=comando.xml -param servicio=plafones -param on=true -param id=1 comando.xq
2cp0021\n\r@

And here is the piece of code that uses all this stuff:
@QString ConfigSistema::getComando(QString servicio, bool on, int id)
{
QString comando = "null";
QFile instanceFile(getXMLPrincipal());
instanceFile.open(QIODevice::ReadOnly);

QFile xq(":/xquery/xml/xquery/comando.xq");
xq.open(QIODevice::ReadOnly);

QXmlQuery query;
query.bindVariable("inputDocument", &instanceFile);
query.bindVariable("servicio", QXmlItem(QVariant(servicio)));
query.bindVariable("on", QXmlItem(QVariant(on)));
query.bindVariable("id", QXmlItem(QVariant(id)));

if(xq.isOpen()){
query.setQuery(&xq, QUrl::fromLocalFile(xq.fileName()));

QXmlResultItems res;
query.evaluateTo(&res);
QXmlItem item(res.next());
while (!item.isNull()) {
  if (item.isAtomicValue()) {
    QVariant v = item.toAtomicValue();
    if(v.type() == QVariant::String){
      comando = v.toString();
      qDebug() << "getComando()" << comando;
    }
  }
  item = res.next();
}

} else
qDebug() << "not opened" << xq.fileName();

xq.close();
instanceFile.close();

return comando;
}@

After running this method, item is always null when it is supossed to be atomic value containing the expected string.

[johnlubest]

I found the problem, I was giving an incorrect file name for the xml to be processed.

I changed this line:
@QFile instanceFile(getXMLPrincipal());@

I put another fuction as parameter to get the path to the correct file and I got it working.