我的环境:Qt5.5 + QtCreator3.5 + OSX10.11
我知道qt5和qt4中的connect函数的语法是不同的,并且查找文档以弄清楚如何在qt5中使用connect()处理信号/插槽函数的重载。
我按照建议进行操作,但仍然无法正常工作。
报纸
signals:
// overload function
void newPaper(const QString &name) const;
void newPaper(const QString &name, const QDate &date) const;
读者
//overload function
void receiveNewspaper(const QString &name) const
{
qDebug() << "overload(name): Receives Newspaper: " << name;
}
//overload function
void receiveNewspaper(const QString &name, const QDate &date) const
{
qDebug() << "overload(name, date): Receives Newspaper: " << name << "\tDate:" << date;
}
main.cpp
//connect for overload signal,slot function
QObject::connect(&newspaper,
static_cast<void (Newspaper:: *)(const QString &)>(&Newspaper::newPaper),
&reader,
static_cast<void (Reader:: *)(const QString &)>(&Reader::receiveNewspaper) );
但是它得到如下错误
./2_16_SignalSlotDeep/main.cpp:16:22: error: address of overloaded function 'newPaper' cannot be static_cast to type 'void (Newspaper::*)(const QString &)'
static_cast<void (Newspaper::*)(const QString &)>(&Newspaper::newPaper),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../2_16_SignalSlotDeep/newspaper.h:28:10: note: candidate function
void newPaper(const QString &name) const;
^
../2_16_SignalSlotDeep/newspaper.h:29:10: note: candidate function
void newPaper(const QString &name, const QDate &date) const;
^
../2_16_SignalSlotDeep/main.cpp:18:22: error: address of overloaded function 'receiveNewspaper' cannot be static_cast to type 'void (Reader::*)(const QString &)'
static_cast<void (Reader::*)(const QString &)>(&Reader::receiveNewspaper) );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../2_16_SignalSlotDeep/reader.h:16:10: note: candidate function
void receiveNewspaper(const QString &name) const
^
../2_16_SignalSlotDeep/reader.h:21:10: note: candidate function
void receiveNewspaper(const QString &name, const QDate &date) const
我已经搜索了其他对我没有帮助的问题。如何解决?您的建议将不胜感激。
您不能使用static_cast丢弃信号的“常量”。尝试删除信号背后的“常量”。
通常,信号不需要是常量,因为它们通常以非常量方法发出。
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