[英]QT5 Radio button signal not compatible with function, even though it should be
根據QT5文檔,QRadioButton繼承了QAbstractButton的4個信號 ,其中包括單擊的信號。 clicked(bool checked = false)
它的模板clicked(bool checked = false)
所以我感到困惑,為什么這段代碼返回一個很長的錯誤消息,其中一部分是error: static assertion failed: Signal and slot arguments are not compatible
。
代碼(簡體,可能包含不屬於原始代碼的錯誤):
#include <QApplication>
#include <QMainWindow>
#include <QRadioButton>
#include <iostream>
class front_end : public QWidget
{
Q_OBJECT
public:
void load()
{
auto *rbtn_0 = new QRadioButton(tr("Reference"), this);
rbtn_0->setChecked(true);
QObject::connect(rbtn_0, &QRadioButton::clicked, this, SLOT(rbtn_toggle(bool)));
}
public slots:
void rbtn_toggle(bool arg_0)
{
std::cout << "Toggle\n";
}
};
int main(int argc, char *argv[]) {
QApplication app(argc, argv);
front_end FrontEnd;
FrontEnd.load();
return app.exec();
}
編譯:
qmake -project -norecursive -Wall -Wparser -o main.pro;
echo "QT += widgets" >> main.pro;
echo "CONFIG += c++11" >> main.pro;
qmake -norecursive main.pro;
make;
錯誤信息:
g++ -c -m64 -pipe -O2 -std=c++0x -Wall -W -D_REENTRANT -fPIE -DQT_NO_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++-64 -I. -I. -I/usr/include/qt5 -I/usr/include/qt5/QtWidgets -I/usr/include/qt5/QtGui -I/usr/include/qt5/QtCore -I. -o main.o main.cpp
main.cpp:21:8: warning: unused parameter ‘arg_0’ [-Wunused-parameter]
void rbtn_toggle(bool arg_0)
^
In file included from /usr/include/qt5/QtCore/qcoreapplication.h:48:0,
from /usr/include/qt5/QtWidgets/qapplication.h:45,
from /usr/include/qt5/QtWidgets/QApplication:1,
from main.cpp:1:
/usr/include/qt5/QtCore/qobject.h: In instantiation of ‘static typename QtPrivate::QEnableIf<(QtPrivate::FunctionPointer<Func2>::ArgumentCount == (-1)), QMetaObject::Connection>::Type QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, const QObject*, Func2, Qt::ConnectionType) [with Func1 = void (QAbstractButton::*)(bool); Func2 = const char*; typename QtPrivate::QEnableIf<(QtPrivate::FunctionPointer<Func2>::ArgumentCount == (-1)), QMetaObject::Connection>::Type = QMetaObject::Connection; typename QtPrivate::FunctionPointer<Func>::Object = QAbstractButton]’:
main.cpp:17:83: required from here
/usr/include/qt5/QtCore/qobject.h:300:122: warning: overflow in implicit constant conversion [-Woverflow]
const int FunctorArgumentCount = QtPrivate::ComputeFunctorArgumentCount<Func2 , typename SignalType::Arguments>::Value;
^
In file included from /usr/include/qt5/QtCore/qcoreapplication.h:45:0,
from /usr/include/qt5/QtWidgets/qapplication.h:45,
from /usr/include/qt5/QtWidgets/QApplication:1,
from main.cpp:1:
/usr/include/qt5/QtCore/qglobal.h:669:47: error: static assertion failed: Signal and slot arguments are not compatible.
#define Q_STATIC_ASSERT_X(Condition, Message) static_assert(bool(Condition), Message)
^
/usr/include/qt5/QtCore/qobject.h:302:9: note: in expansion of macro ‘Q_STATIC_ASSERT_X’
Q_STATIC_ASSERT_X((FunctorArgumentCount >= 0),
^
In file included from /usr/include/qt5/QtCore/qobjectdefs.h:47:0,
from /usr/include/qt5/QtCore/qobject.h:48,
from /usr/include/qt5/QtCore/qcoreapplication.h:48,
from /usr/include/qt5/QtWidgets/qapplication.h:45,
from /usr/include/qt5/QtWidgets/QApplication:1,
from main.cpp:1:
/usr/include/qt5/QtCore/qobjectdefs_impl.h: In instantiation of ‘struct QtPrivate::FunctorReturnType<const char*, QtPrivate::List<> >’:
/usr/include/qt5/QtCore/qobject.h:305:158: required from ‘static typename QtPrivate::QEnableIf<(QtPrivate::FunctionPointer<Func2>::ArgumentCount == (-1)), QMetaObject::Connection>::Type QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, const QObject*, Func2, Qt::ConnectionType) [with Func1 = void (QAbstractButton::*)(bool); Func2 = const char*; typename QtPrivate::QEnableIf<(QtPrivate::FunctionPointer<Func2>::ArgumentCount == (-1)), QMetaObject::Connection>::Type = QMetaObject::Connection; typename QtPrivate::FunctionPointer<Func>::Object = QAbstractButton]’
main.cpp:17:83: required from here
/usr/include/qt5/QtCore/qobjectdefs_impl.h:633:78: error: request for member ‘operator()’ in ‘QtPrivate::FunctorReturnType<Functor, QtPrivate::List<Tail ...> >::dummy<const char*>()’, which is of non-class type ‘const char*’
typedef decltype(dummy<Functor>().operator()((dummy<ArgList>())...)) Value;
是的,我知道將信號語法更改為QT4標准“ SIGNAL(clicked(bool))”會解決該問題,但是我正試圖擺脫該語法,更重要的是,理解問題所在。
您正在混合舊語法和新語法。 每個呼叫選擇一個以連接/斷開連接。 對於重載的信號/插槽,在使用新語法的情況下,您需要將函數指針轉換為正確的類型
我在stackoverflow上搜索了這種類型的問題,但沒有找到任何東西,直到Silicomancer指出了一篇非常出色的文章 -Part / Rule 5。
閱讀此內容后,解決方案很簡單:
QObject::connect(rbtn_0, &QRadioButton::clicked, this, &front_end::rbtn_toggle);
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.