我可以为 QObject 的子类设置复制构造函数吗? [英] Could I have copy constructor for subclass of QObject?

问题描述

这里 我们可以读到没有复制构造和复制赋值运算符可评估.但是这里我们可以读到qRegisterMetaType 和 Q_DECLARE_METATYPE 必须有公共默认构造函数、公共复制构造函数和公共析构函数.问题是:谁在说谎?还是我没有正确理解?

Here we can read that no copy construct and copy assignment operator evaluable. But here we can read that qRegisterMetaType and Q_DECLARE_METATYPE have to have public default constructor, public copy constructor and public destructor. The question is: who is telling a lie? Or I did not understand it correctly?

推荐答案

一切都是真的:
1.QObject不能被复制，它的所有后代也不能被复制.
2. Q_DECLARE_METATYPE 接受带有公共构造函数、复制构造函数和析构函数的对象.

Everything is true:
1. QObject can't be copied and all its descendants can't be copied also.
2. Q_DECLARE_METATYPE accepts objects with public constructor, copy constructor and destructor.

没有矛盾，因为你不能用Q_DECLARE_METATYPE注册QObject后代.

There is no contradiction, because you can't register QObject descendants with Q_DECLARE_METATYPE.

当您将类转换为 QVariant 时，它使用复制构造函数来复制您的对象:

When you convert your class to QVariant it uses a copy constructor to make a copy of your object:

 void *ptr = QMetaType::construct(x->type, copy);

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