Qt:信号和插槽错误:未定义对`vtable 的引用 [英] Qt: Signals and slots Error: undefined reference to `vtable for

问题描述

以下链接示例:http://developer.kde.org/documentation/books/kde-2.0-development/ch03lev1sec3.html

#include <QObject>
#include <QPushButton>
#include <iostream>
using namespace std;

class MyWindow : public QWidget
{
    Q_OBJECT  // Enable slots and signals
    public:
        MyWindow();
    private slots:
        void slotButton1();
        void slotButton2();
        void slotButtons();
    private:
        QPushButton *button1;
        QPushButton *button2;
};

MyWindow :: MyWindow() : QWidget()
{
    // Create button1 and connect button1->clicked() to this->slotButton1()
    button1 = new QPushButton("Button1", this);
    button1->setGeometry(10,10,100,40);
    button1->show();
    connect(button1, SIGNAL(clicked()), this, SLOT(slotButton1()));

    // Create button2 and connect button2->clicked() to this->slotButton2()
    button2 = new QPushButton("Button2", this);
    button2->setGeometry(110,10,100,40);
    button2->show();
    connect(button2, SIGNAL(clicked()), this, SLOT(slotButton2()));

    // When any button is clicked, call this->slotButtons()
    connect(button1, SIGNAL(clicked()), this, SLOT(slotButtons()));
    connect(button2, SIGNAL(clicked()), this, SLOT(slotButtons()));
}

// This slot is called when button1 is clicked.
void MyWindow::slotButton1()
{
    cout << "Button1 was clicked" << endl;
}

// This slot is called when button2 is clicked
void MyWindow::slotButton2()
{
    cout << "Button2 was clicked" << endl;
}

// This slot is called when any of the buttons were clicked
void MyWindow::slotButtons()
{
    cout << "A button was clicked" << endl;
}

int main ()
{
    MyWindow a;
}

结果:

    [13:14:34 Mon May 02] ~/junkPrograms/src/nonsense  $make
g++ -c -m64 -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/opt/qtsdk-2010.05/qt/mkspecs/linux-g++-64 -I. -I/opt/qtsdk-2010.05/qt/include/QtCore -I/opt/qtsdk-2010.05/qt/include/QtGui -I/opt/qtsdk-2010.05/qt/include -I. -I. -o signalsSlots.o signalsSlots.cpp
g++ -m64 -Wl,-O1 -Wl,-rpath,/opt/qtsdk-2010.05/qt/lib -o nonsense signalsSlots.o    -L/opt/qtsdk-2010.05/qt/lib -lQtGui -L/opt/qtsdk-2010.05/qt/lib -L/usr/X11R6/lib64 -lQtCore -lpthread
signalsSlots.o: In function `MyWindow::MyWindow()':
signalsSlots.cpp:(.text+0x1a2): undefined reference to `vtable for MyWindow'
signalsSlots.cpp:(.text+0x1aa): undefined reference to `vtable for MyWindow'
signalsSlots.o: In function `MyWindow::MyWindow()':
signalsSlots.cpp:(.text+0x3e2): undefined reference to `vtable for MyWindow'
signalsSlots.cpp:(.text+0x3ea): undefined reference to `vtable for MyWindow'
signalsSlots.o: In function `main':
signalsSlots.cpp:(.text+0x614): undefined reference to `vtable for MyWindow'
signalsSlots.o:signalsSlots.cpp:(.text+0x61d): more undefined references to `vtable for MyWindow' follow
collect2: ld returned 1 exit status
make: *** [nonsense] Error 1

vtable 是用于虚函数的，AFAIK，这里出错的原因是什么?

vtable is for virtual functions, AFAIK, what's the reason of error here?

推荐答案

看起来 moc 没有为您的 QObject 生成代码，因为您在 .cpp 中声明了它> 文件.解决此问题的最简单方法是将 MyWindow 的声明移动到标题中，并将标题添加到 .proHEADERS 列表中> 文件:

It looks like moc doesn't generate code for your QObject because you declare it in the .cpp file. The easiest way to fix that is to move the declaration of MyWindow to a header, and add the header to the HEADERS list, in the .pro file:

HEADERS += yourheader.h 

然后重新运行qmake.

(请注意，您所看的 KDE 2.0 书籍已经过时了)

(Please note that the KDE 2.0 book you look at is vastly outdated)

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