Converting a list/array to JSON - performance issue.

Mathan M

Hi,

I want to pass the PortalSearchItems list to be passed from qml to Cpp. Eventhough, I can get the result, app got just killed, when this code executes. I assume performance issue.

Code Snippet: main.qml

var varidPortalSearchItemsCount = idPortalSearchItems.totalResults;

var vartextJson = "";

for (var ii = 0; ii <= varidPortalSearchItemsCount -1 ;ii++)
{
vartextJson += '{"title":"'+ idPortalSearchItems.results[ii].title +'"
,"owner":"'+ idPortalSearchItems.results[ii].owner +'"
,"url":"'+ idPortalSearchItems.results[ii].url +'"
,"itemId":"'+ idPortalSearchItems.results[ii].itemId +'"
}' + ',';
}


vartextJson = vartextJson.substring(0, vartextJson.length-1) + ']';
vartextJson = '[' + vartextJson;
var varJsonString =JSON.parse(vartextJson);
objHomeController.eveWriteXML(varJsonString);

HomeController.h

Q_INVOKABLE bool eveWriteXML(const QJsonObject &pqvarPortalItemResult);

HomeController.cpp

bool HomeController::eveWriteXML(const QJsonObject &pqvarPortalItemResult)
{

QVariantMap jsonQVariantMap = pqvarPortalItemResult.toVariantMap();



for(QVariantMap::const_iterator iter = jsonQVariantMap.begin(); iter != jsonQVariantMap.end(); ++iter) {

QVariant objQVariant = iter.key();
QVariant objQVariant1 = iter.value();

QString strTitleValue = objQVariant1.toMap().values("title").value(0).toSt ring();
QString strUrlValue = objQVariant1.toMap().values("url").value(0).toStri ng();
QString strOwnerValue = objQVariant1.toMap().values("owner").value(0).toSt ring();
QString strItemIdValue = objQVariant1.toMap().values("itemId").value(0).toS tring();

}

Thanks In advance.

p3c0

@Mathan-M
Not sure about the performance issues but the way you are trying to extract JSON values seems to be wrong. iter.value() is going to return a QVariant of QString's because
idPortalSearchItems.results[ii].title, idPortalSearchItems.results[ii].owner ... are all strings.
So it should be replaced as:

QVariant v = iter.value();
QString strTitleValue = v.toString();
...

SGaist

Hi,

What does a run through the debugger tell you ?

p3c0

@Mathan-M
Not sure about the performance issues but the way you are trying to extract JSON values seems to be wrong. iter.value() is going to return a QVariant of QString's because
idPortalSearchItems.results[ii].title, idPortalSearchItems.results[ii].owner ... are all strings.
So it should be replaced as:

QVariant v = iter.value();
QString strTitleValue = v.toString();
...

Mathan M

Re: Converting a list/array to JSON - performance issue.

Hi p3c0,

Thanks for Help.

Mathan