How to parse Json array object? - json

Question

I am trying to parse a Json file in Qt application but i am stuck at a point.
I have a json file which contains arrays with properties. Now i have a Category class which has a items as member variable. Now i would like to parse the properties and create a unique category object and under this object i would like to add the properties.
I have achieved this by hardcoding:
auto vehicle = std::make_unique<Item>("Coordinates");
vehicle->addEntry(std::make_unique<PropertyItem>("TODO", "x", PropertyType::FLOAT, false, *vehicle.get()));
categories.emplace_back(std::move(vehicle));
void Model::loadItemsFromJson() {
// Vehicle
QJsonObject obj = loadJsonFile(":/jsonfiles/vehicle.json");
QJsonArray properties = obj["properties"].toArray();
/// No idea here how to achive
}
Should i change the Json for better handling or could this be achieved easily?
Thank you
--------------------------EDIT---------------------
Now my json looks like this:
{
"General": [{
"Address": "TODO",
"Readonly": false
},
],
"Coordinates": [{
"Address": "TODO",
"Readonly": false
}
]
]
}
and my implementation:
QJsonObject obj = loadJsonFile(":/jsonfiles/vehicle.json");
QVariantMap map = obj.toVariantMap();
for (auto& m : map.keys()) {
// How to create objects??
}

Answer 1

If you structure your JSON like your objects, e.g.
{
"Categories" : {
"General" : [{
"Address" : "TODO",
"Name" : "Name",
"Type" : "string",
"ReadOnly" : "true"
}, ...],
"World Coordinates" : [...]
}
Then you just parse out each CategoryItem and ScenarioPropertyItem
PropertyType toPropertyType(QJsonValue value); // forward declare
void ScenarioPropertiesModel::loadItemsFromJson() {
// Vehicle
QJsonObject obj = loadJsonFile(":/jsonfiles/vehicle.json")["Categories"].toObject();
for (auto & cat : obj)
{
auto category = std::make_unique<CategoryItem>(cat.name());
for (auto & prop : cat.value().toArray())
{
auto address = prop["Address"].toString();
auto name = prop["Name"].toString();
auto type = toPropertyType(prop["Type"]);
auto readonly = prop["Readonly"].toBool();
category->addEntry(std::make_unique<ScenarioPropertyItem>(address, name, type, readonly));
}
categories.emplace_back(std::move(category));
}
}
PropertyType toPropertyType(QJsonValue value)
{
static std::map<QString, PropertyType> propertyTypes =
{
{ "float", PropertyType::FLOAT },
{ "string", PropertyType::String },
// etc
}
return propertyTypes[value.toString()];
}