QJsonDocument, array method to create QJsonArray?

[SPlatten]

I have created an instance of QJsonDocument:

    QJsonDocument docJSON = QJsonDocument::fromJson(cpszJSON);

I can see the docJSON has a method array, how do I extract the array from it and convert to an instance of QJsonArray.

I've tried using it to initialise an instance of QJsonArray, but there are syntax errors.

I want to get the number of elements in the array and pass each element.

[Christian Ehrlicher]

https://doc.qt.io/qt-5/qtcore-serialization-savegame-example.html

[JonB]

@SPlatten
If your JSON source has arrays in it, your QJsonDocument::fromJson()-generated document should have QJsonArrays in it? And you walk/find them like any other JSON element.

Use the QJsonDocument QJsonDocument::fromJson(const QByteArray &json, QJsonParseError *error = nullptr) to pass in a &error to get clues about syntax errors.

[SPlatten]

@SPlatten said in QJsonDocument, array method to create QJsonArray?:

stance of QJsonArray, but there are syntax errors.

Is there any good example on how to extract the array from the document?

[Christian Ehrlicher]

https://doc.qt.io/qt-5/qtcore-serialization-savegame-example.html

[SPlatten]

Thank you, I see that there are functions isArray and toArray, what is the array function, I cannot see how to use that?

[SGaist]

Hi,

Do you mean the QJsonDocument::array method ?

As the documentation says, it returns the array contained in the document.

[SPlatten]

Yes, I get that but you cannot assign the array the function returns to a QJsonArray.

[JonB]

@SPlatten
I don't understand. It returns the QJsonArray if the (top-level of) the QJsonDocument is a QJsonArray . Why do you want to assign that to a QJsonArray? If you really want to, there are things like QJsonArray::QJsonArray(const QJsonArray &other) or QJsonDocument::setArray(const QJsonArray &array), but not sure what you are trying to achieve.

[SPlatten]

Try it yourself, I have, you can't there is a problem:

    calling 'array' with incomplete return type 'QJsonArray'  variable has incomplete type 'QJsonArray'.

[SGaist]

You forgot

#include <QJsonArray>

in the file where you use that method.