unexpected result in parsing nested json in qt (array does not exist) - c++

Question

I am new in qt and I also searched in stack overflow but I can't get my answer so this not a duplicated post because all similar post have array [] but in this code i have not any array
I want to parse this complex JSON file:
{
"query": {
"lang": "en-US",
"results": {
"channel": {
"units": {
"distance": "mi",
"pressure": "in"
},
"ttl": "60",
"location": {
"city": "city",
"country": "not important",
"region": " kkk"
},
"wind": {
"chill": "99",
"direction": "180",
"speed": "14"
}
}
...(more code)
i want to get chill data but out put is " " , please help me to print chill data in qt
its a part of my code:
QNetworkAccessManager manager;
QNetworkReply *response = manager.get(QNetworkRequest(QUrl(url)));
QEventLoop event;
connect(response, SIGNAL(finished()), &event, SLOT(quit()));
event.exec();
json = response->readAll();
QJsonDocument doc = QJsonDocument::fromJson(json.toUtf8());
QJsonObject jsonObj = doc.object();
foreach (const QJsonValue &value, jsonObj) {
QJsonObject jsonobj = value.toObject();
qDebug() << jsonobj["chill"].toString();
}
output of qDebug()<<doc.object(); is
D/libuntitled7.so(13258): : ** QJsonObject({"query":{"count":1,"created":"2017-07-06T21:21:16Z","lang":"en-US","results":{"channel":{"astronomy":{"sunrise":"5:48 am","sunset":"8:15 pm"},"atmosphere":{"humidity":"16","pressure":"875.0","rising":"0","visibility":"16.1"},"description":"Yahoo! Weather","image":{"height":"18","link":"http://weather.yahoo.com","title":"Yahoo! Weather","url":"http://l.yimg.com/a/i/brand/purplelogo//uh/us/news-wea.gif","width":"142"},"item":{"condition":{"code":"31","date":"Fri, 07 Jul 2017 12:30 AM IRDT","temp":"85","text":"Clear"},"description":"<![CDATA[<img src=\"http://l.yimg.com/a/i/us/we/52/31.gif\"/>\n<BR/>\n<b>Forecast:</b>\n<BR /> Fri - Sunny. High: 97Low: 78\n<BR /> Sat - Sunny. High: 100Low: 79\n<BR /> Sun - Sunny. High: 101Low: 81\n<BR /> Mon - Sunny. High: 100Low: 81\n<BR /> Tue - Mostly
D/libuntitled7.so(13258): ..\untitled7\dialog2.cpp:84 (void Dialog2::on_pushButton_clicked()):
and next out put is 86

Answer 1

As I comment #MohammedB.B. a way is to manually search through the keys, another way is to create a function that searches through the keys, in this case I present the second form:
QJsonObject findObject(QString key, QJsonObject object){
if(object.isEmpty())
return QJsonObject();
if(object.keys().contains(key)){
return object;
}
else{
for(const QString& _key: object.keys()){
if(object[_key].isObject()){
const QJsonObject& result = findObject(key, object[_key].toObject());
if(!result.isEmpty()){
return result;
}
}
}
}
return QJsonObject();
}
QJsonValue findValuebyKey(QString key, QJsonDocument doc){
QJsonObject obj_key = findObject(key, doc.object());
return obj_key[key];
}
Example:
QJsonDocument doc = QJsonDocument::fromJson(json.toUtf8());
qDebug()<<findValuebyKey("chill", doc).toString();
Output:
"99"
Note:If you generate problems the "for" enable c ++ 11, you can do this by adding CONFIG += c++11 to your .pro

Answer 2

You need to iterate in your channels array too. Easy solution:
const QJsonDocument doc = QJsonDocument::fromJson(response->readAll().toUtf8());
// Access to "query"
const QJsonObject queryObject = doc.object();
// Access to "results"
const QJsonObject resultsObject = queryObject.value("results").toObject();
// Access to "chanels"
const QJsonObject channelsObject = resultsObject.value("channels").toObject();
// Access to "wind"
const QJsonObject windObject = channelsObject.value("wind").toObject();
// And then access to "chill"
const QJsonValue chill = windObject.value("chill");
Best practice its to create a recursive function to parse the JSON recursively.