Transfer of a QByteArray to main.cpp

[ChrisW67]

This line of main.cpp:

mainWidget w(const QUrl &Urlh);

mainWidget w(const QUrl &Urlh);

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is not what you think it is. This is a declaration of a function w() that takes a QUrl and returns a mainWidget (that function does not exist). What you are trying to do is construct a mainWidget object and provide its constructor with an argument (a QUrl value) thus:

mainWidget w(histUrl);
w.show();

mainWidget w(histUrl);
w.show();

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This is precisely the same sort of thing you do in the mainWidget constructor when you pass the QUrl value into the FileDownloader constructor.

What is at line 22 of filedownloader.h?

Edit: Answered my own question

Line 22 of filedownloader.h must be this one:

void DataA(m_DownloadedData);

void DataA(m_DownloadedData);

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The header is a declaration not an implementation. You are declaring a function DataA(...) that returns nothing and takes an argument. The stuff in the parentheses is the type (and optionally name) of the argument. What you have supplied is a name that is unknown as a type: hence the error. What you should be doing is:

void DataA(const QByteArray &someName);

void DataA(const QByteArray &someName);

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While this is a Qt signal, to C++ it is simply another function. The implementation of this function is provided by the Qt tools (moc), which is why you do not need/see this function implemented in filedownloader.cpp.


It seems that a lack of understanding of C++, not Qt, is a reasonable part of the problems here. Rather than run up a white flag perhaps taking a step back and doing some generic C++ tutorials would be useful.