QJsonArray, type question

SPlatten

I am working with the QJson classes and putting together a descriptive string using the methods available. One such method is type(). I see in the debugger that if I test a QJsonValue for it's type using isArray() it returns true which is correct in the case I'm testing, but what I don't understand is when I then use:

QMetaType::typeName(jsonValue.type());

What I'm seeing returned for an array is:

qlonglong

Why? Is this a bug? Shouldn't it be array?

The other types seem correct.

Here is the code that creates the object:

QJsonArray aryTest;
QJsonObject objTest;
QJsonObject test;
aryTest.insert(0, QJsonValue("a"));
aryTest.insert(1, QJsonValue("b"));
aryTest.insert(2, QJsonValue("c"));
test.insert("aryTest", aryTest);
objTest.insert("a", QJsonValue("d"));
objTest.insert("b", QJsonValue("e"));
objTest.insert("c", QJsonValue("f"));
test.insert("objTest", objTest);

Something is clearly wrong, when I single step through this object, for the first element and the QJsonValue("a"), I'm actually getting:

0 for the index which is correct, but "uint" for the type which isn't correct, the value is "a" which is also correct.

On searching for a solution it seems that the only supported types are:

QJsonValue::Null	Empty QVariant
QJsonValue::Bool	QMetaType::Bool
QJsonValue::Double	QMetaType::Double
QJsonValue::String	QString
QJsonValue::Array	QVariantList
QJsonValue::Object	QVariantMap
QJsonValue::Undefined	Empty QVariant

And it looks like I will need to revert back to my original method which was a QStringList of types.

SPlatten

My solution, static array of types, values obtained from https://doc.qt.io/qt-5/qjsonvalue.html#Type-enum:

QString clsScriptHelper::strType(QJsonValue::Type type) {
    static const uint8_t scuint8Undefined = 0x80
                        ,scuint8UndefinedIdx = 6;
    static const char* scpszTypes[] = {"Null"       /*0*/
                                      ,"Bool"       /*1*/
                                      ,"Double"     /*2*/
                                      ,"String"     /*3*/
                                      ,"Array"      /*4*/
                                      ,"Object"     /*5*/
                                      ,"Undefined"  /*6*/
                                        };
    uint8_t uint8Idx = scuint8Undefined;

    if ( type != scuint8Undefined ) {
        uint8Idx = static_cast<uint8_t>(type);
    }
    if ( uint8Idx >= scuint8Undefined ) {
        uint8Idx = scuint8UndefinedIdx;
    }
    return scpszTypes[uint8Idx];
}```

Christian Ehrlicher

Please provide some compilable code - I don't understand the problem or where you call jsonValue.type() or the problem with the first element.

SPlatten

@Christian-Ehrlicher I think it was pretty obvious, the QJson classes have a ::type function that returns a numeric representation of the type, there isn't a function that translates this into a string.

That's what I wanted.

Christian Ehrlicher

It returns a QMetaType so you should take a look for such a function there and not in the json classes.