Inaccessible conversion in QObject

Question

Here is my sample code:

class hoho : public QObject {     Q_OBJECT public:     hoho()      {         httpFetch = new HttpFetch(QUrl("http://www.google.com/"));         connect(httpFetch, SIGNAL(Fetched()), this, SLOT(PrintData(QByteArray)));     }      void PrintData(QByteArray http)     {         qDebug()<<http;     }      HttpFetch *httpFetch; }; 

When I try to compile this, following error pops up

1>main.cpp(15): error C2243: 'type cast' : conversion from 'HttpFetch *' to 'const QObject *' exists, but is inaccessible 

This error comes as the class is derived from QObject (which is necessary for signal and slot mechanism).

Can anyone tell me how to fix this?

Answer 1

You probably did not derive HttpFetch publicly, but privately from QObject. So just change

class HttpFetch : QObject { // ... 

to

class HttpFetch : public QObject { // ... 

and it should work.

Answer 2

If your design requires to make the inheritance non-public (I had this requirement because I inherited from a QWidget for a multithreading purpose and didn't want to expose all functions to the user), you can do this:

class FilesQueueQList : protected QWidget {     Q_OBJECT  public:     using QWidget::QObject; //This is the solution! //... } 

Now the members of QWidget are private/protected, but QObject is accessible as public.