Question

我想从命令行编译单个文件QT应用程序，以便快速测试一些功能。请参阅下面的文件代码。

我正在编译：

qmake -project && qmake && make

我得到了这个错误：

Togglebutton.o:Togglebutton.cpp:function ButtonDialog::ButtonDialog(QWidget*): error: undefined reference to 'vtable for ButtonDialog'
Togglebutton.o:Togglebutton.cpp:function ButtonDialog::ButtonDialog(QWidget*): error: undefined reference to 'vtable for ButtonDialog'
Togglebutton.o:Togglebutton.cpp:function ButtonDialog::~ButtonDialog(): error: undefined reference to 'vtable for ButtonDialog'
Togglebutton.o:Togglebutton.cpp:function ButtonDialog::~ButtonDialog(): error: undefined reference to 'vtable for ButtonDialog'

我不是c ++大师，我试图谷歌关于vtable的未定义引用，但我不会理解为什么我也会在一个文件中收到此错误..

有人可以帮我理解未定义的vtable错误吗？

/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
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 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <QPushButton>
#include <QHBoxLayout>
#include <QMessageBox>

#include <QApplication>
#include <QDialog>
class QPushButton;

class ButtonDialog : public QDialog
{
  Q_OBJECT

public:
  ButtonDialog( QWidget *parent=0 );

private slots:
  void buttonClicked();
  void buttonToggled();

private:
  QPushButton *clickButton;
  QPushButton *toggleButton;
};

ButtonDialog::ButtonDialog( QWidget *parent ) : QDialog( parent )
{
  clickButton = new QPushButton( "Click me!", this );
  toggleButton = new QPushButton( "Toggle me!", this );
  toggleButton->setCheckable( true );

  QHBoxLayout *layout = new QHBoxLayout( this );
  layout->addWidget( clickButton );
  layout->addWidget( toggleButton );

  connect( clickButton, SIGNAL(clicked()), this, SLOT(buttonClicked()) );
  connect( toggleButton, SIGNAL(clicked()), this, SLOT(buttonToggled()) );
}

void ButtonDialog::buttonClicked()
{
  QMessageBox::information( this, "Clicked!", "The button was clicked!" );
}

void ButtonDialog::buttonToggled()
{
  QMessageBox::information( this, "Toggled!", QString("The button is %1!").arg(toggleButton->isChecked()?"pressed":"released") );
}


int main( int argc, char **argv )
{
  QApplication app( argc, argv );

  ButtonDialog dlg;
  dlg.show();

  return app.exec();
}

Answer 1

当我在cpp文件中声明Q_OBJECT类时，我犯了同样的错误。创建一个标题并在那里移动类声明。

从命令行编译Qt单个文件：未定义引用到vtable

1 个答案: