QtConcurrent-run-inherited-member-function: Difference between revisions

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[[Category:snippets]]
[[Category:HowTo]]
 
[toc align_right="yes" depth="3"]
 
To call an inherited member function of an object using QtConcurrent::run, you must cast the member function address to the subclass type.
To call an inherited member function of an object using QtConcurrent::run, you must cast the member function address to the subclass type.


Line 12: Line 9:


#include "ui_form.h"
#include "ui_form.h"
#include "MyClass.h"
#include "MyClass.h"


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public slots:
public slots:
 
void slot_finished();
void slot_finished();
  void on_pushButton_clicked();
  void on_pushButton_clicked();


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private:
private:
  ChildClass MyObject;
  ChildClass MyObject;
};
};


#endif
#endif
</code>
</code>


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#include <iostream>
#include <iostream>


Form::Form(QWidget '''parent)
Form::Form(QWidget *parent)
  : QWidget(parent)
  : QWidget(parent)
{
{
  setupUi(this);
  setupUi(this);
}
}


void Form::on_pushButton_clicked()
void Form::on_pushButton_clicked()
{
{
  QFuture<void> future = QtConcurrent::run(&amp;this->MyObject, static_cast<void(ChildClass::''')()>(&amp;ChildClass::LongFunction));// works
  QFuture<void> future = QtConcurrent::run(&this->MyObject, static_cast<void(ChildClass::*)()>(&ChildClass::LongFunction));
}
}
</code>
</code>


== form.ui ==
== form.ui ==


<code>
<code lang="xml">
<?xml version="1.0" encoding="UTF-8"?>
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<ui version="4.0">
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  <connections/>
  <connections/>
</ui>
</ui>
</code>
</code>


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{
{
public:
public:
 
virtual void LongFunction() {
virtual void LongFunction()
  for( int count = 0; count < 5; count++ ) {
{
  sleep( 1 );
for( int count = 0; count < 5; count++ )
  std::cout << "Ping long!" << std::endl;
{
  }
sleep( 1 );
std::cout << "Ping long!" << std::endl;
}
  }
  }
};
};
Line 120: Line 107:
{
{
public:
public:
 
void LongFunction() {
void LongFunction()
  for( int count = 0; count < 5; count++ ) {
{
  sleep( 1 );
for( int count = 0; count < 5; count++ )
  std::cout << "Ping long!" << std::endl;
{
  }
sleep( 1 );
std::cout << "Ping long!" << std::endl;
}
  }
  }
};
};


#endif
#endif
</code>
</code>


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#include <QObject>
#include <QObject>
#include <QThread>
#include <QThread>
#include <iostream>
#include <iostream>


#include "form.h"
#include "form.h"


int main(int argc, char*argv[])
int main(int argc, char*argv[]) {
{
  QApplication app(argc, argv);
  QApplication app(argc, argv);
 
Form form;
Form form;
form.show();
 
return app.exec();
form.show();
 
return app.exec();
}
}
</code>

Latest revision as of 02:22, 18 May 2017

To call an inherited member function of an object using QtConcurrent::run, you must cast the member function address to the subclass type.

form.h

#ifndef FORM_H
#define FORM_H

#include "ui_form.h"
#include "MyClass.h"

class Form : public QWidget, private Ui::Form
{
Q_OBJECT

public slots:
 void slot_finished();
 void on_pushButton_clicked();

public:
 Form(QWidget *parent = 0);

private:
 ChildClass MyObject;
};

#endif

form.cpp

#include <QtGui>
#include <QImage>

#include "form.h"
#include "MyClass.h"

#include <iostream>

Form::Form(QWidget *parent)
 : QWidget(parent)
{
 setupUi(this);
}

void Form::on_pushButton_clicked()
{
 QFuture<void> future = QtConcurrent::run(&this->MyObject, static_cast<void(ChildClass::*)()>(&ChildClass::LongFunction));
}

form.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>Form</class>
 <widget class="QWidget" name="Form">
 <property name="geometry">
 <rect>
 <x>0</x>
 <y>0</y>
 <width>400</width>
 <height>300</height>
 </rect>
 </property>
 <property name="windowTitle">
 <string>Form</string>
 </property>
 <layout class="QVBoxLayout" name="verticalLayout">
 <item>
 <widget class="QPushButton" name="pushButton">
 <property name="text">
 <string>PushButton</string>
 </property>
 </widget>
 </item>
 </layout>
 </widget>
 <resources/>
 <connections/>
</ui>

MyClass.h

#ifndef MyClass_H
#define MyClass_H

#include <iostream>

class ParentClass
{
public:
 virtual void LongFunction() {
  for( int count = 0; count < 5; count++ ) {
   sleep( 1 );
   std::cout << "Ping long!" << std::endl;
  }
 }
};

class ChildClass : public ParentClass
{
public:
 void LongFunction() {
  for( int count = 0; count < 5; count++ ) {
   sleep( 1 );
   std::cout << "Ping long!" << std::endl;
  }
 }
};

#endif

main.cpp

#include <QApplication>
#include <QObject>
#include <QThread>
#include <iostream>

#include "form.h"

int main(int argc, char*argv[]) {
 QApplication app(argc, argv);
 Form form;
 form.show();
 return app.exec();
}