Hello,

How do you stream a custom QVariant? I'm getting an error when using QDataStream to output to a binary file. Error is noted in code below.

Where does the type (i.e. QVariant::Type) get specified? Is this done automatically by Q_DECLARE_METATYPE? I was trying to declare my own value (beyond QVariant::UserType), but I couldn't see where to accomplish it. It appears to just be set by defualt to QVariant::UserType, but I need multiple custom types.

I'm hoping to leverage the Qt serialization capabilities ... handling byte-order, string length, etc.

Qt Code: 
  1. QDataStream & operator<<(QDataStream & out, const sStatePacket & record)
  2. {
  3.    QVariant variant;
  4.    variant.setValue(record);
  5.    out << variant;   // ERROR OCCURS HERE!!!
  6.    return out;
  7. }
  8.  
  9. QDataStream & operator>>(QDataStream & in, sStatePacket & record)
  10. {
  11.    QVariant variant;
  12.    in >> variant;
  13.    record.time = variant.value<sStatePacket>().time;
  14.    record.pos = variant.value<sStatePacket>().pos;
  15.    record.hpr = variant.value<sStatePacket>().hpr;
  16.    return in;
  17. }
  18.  
  19. struct sStatePacket
  20. {
  21.    float time;
  22.    sPosRecord pos;
  23.    sRotRecord hpr;
  24. };
  25. Q_DECLARE_METATYPE(sStatePacket)
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Thank you,
Ben