Progress Bar: Difference between revisions

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[[Category:HowTo]]<br />[[Category:Snippets]]<br />[[Category:Tutorial]]
[[Category:HowTo]]
[[Category:Snippets]]
[[Category:Tutorial]]


[toc align_right=&quot;yes&amp;quot; depth=&quot;3&amp;quot;]
[toc align_right="yes" depth="3"]


= Progress Bar =
= Progress Bar =


It is often necessary to display a progress bar while a long operation is happening. The case we are concerned about in this example is when there is no easy way to track the progress of the operation - all that is known is when it is done. There are many ways to do this. You could use a progressBar widget on your widget and run the operation in a different thread (using moveToThread()). This typically requires a special object to be created (a subclass of &quot;QObject&amp;quot;:http://developer.qt.nokia.com/doc/qt-4.8/qobject.html that runs the operation and then emits a finished() signal), which can be a pain if you need to do this for many different operations.
It is often necessary to display a progress bar while a long operation is happening. The case we are concerned about in this example is when there is no easy way to track the progress of the operation - all that is known is when it is done. There are many ways to do this. You could use a progressBar widget on your widget and run the operation in a different thread (using moveToThread()). This typically requires a special object to be created (a subclass of "QObject":http://developer.qt.nokia.com/doc/qt-4.8/qobject.html that runs the operation and then emits a finished() signal), which can be a pain if you need to do this for many different operations.


However, using &quot;QFutureWatcher&amp;quot;:http://developer.qt.nokia.com/doc/qt-4.8/qfuturewatcher.html and &quot;QtConcurrent::run()&quot;:http://developer.qt.nokia.com/doc/qt-4.8/qtconcurrentrun.html#run, this is extremely easy. Below we demonstrate how to use this technique with both a QProgressDialog and a QProgressBar.
However, using "QFutureWatcher":http://developer.qt.nokia.com/doc/qt-4.8/qfuturewatcher.html and "QtConcurrent::run()":http://developer.qt.nokia.com/doc/qt-4.8/qtconcurrentrun.html#run, this is extremely easy. Below we demonstrate how to use this technique with both a QProgressDialog and a QProgressBar.


== QProgressBar Example ==
== QProgressBar Example ==
Line 13: Line 15:
=== form.h ===
=== form.h ===


<code>#ifndef FORM_H<br />#define FORM_H
<code>#ifndef FORM_H
#define FORM_H


#include &quot;ui_form.h&amp;quot;
#include "ui_form.h"


#include &lt;QFutureWatcher&amp;gt;
#include <QFutureWatcher>


#include &quot;MyClass.h&amp;quot;
#include "MyClass.h"


class Form : public QWidget, private Ui::Form<br />{<br />Q_OBJECT
class Form : public QWidget, private Ui::Form
{
Q_OBJECT


public slots:
public slots:


void slot_finished();<br /> void on_pushButton_clicked();
void slot_finished();
void on_pushButton_clicked();


public:<br /> Form(QWidget *parent = 0);
public:
Form(QWidget *parent = 0);


private:<br /> QFutureWatcher&amp;lt;void&amp;gt; FutureWatcher;<br /> MyClass MyObject;<br />};
private:
QFutureWatcher<void> FutureWatcher;
MyClass MyObject;
};


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


=== form.cpp ===
=== form.cpp ===


<code><br />#include &lt;QtGui&amp;gt;<br />#include &lt;QImage&amp;gt;
<code>
#include <QtGui>
#include <QImage>


#include &quot;form.h&amp;quot;
#include "form.h"


#include &lt;iostream&amp;gt;
#include <iostream>


Form::Form(QWidget *parent)<br /> : QWidget(parent)<br />{<br /> setupUi(this);
Form::Form(QWidget *parent)
: QWidget(parent)
{
setupUi(this);


this-&gt;progressBar-&gt;setMinimum(0);<br /> this-&gt;progressBar-&gt;setMaximum(0);<br /> this-&gt;progressBar-&gt;hide();
this->progressBar->setMinimum(0);
this->progressBar->setMaximum(0);
this->progressBar->hide();


connect(&amp;this-&gt;FutureWatcher, SIGNAL (finished()), this, SLOT (slot_finished()));
connect(&amp;this->FutureWatcher, SIGNAL (finished()), this, SLOT (slot_finished()));


}
}


void Form::slot_finished()<br />{<br /> this-&gt;progressBar-&gt;hide();<br />}
void Form::slot_finished()
{
this->progressBar->hide();
}


void Form::on_pushButton_clicked()<br />{<br /> this-&gt;progressBar-&gt;show();
void Form::on_pushButton_clicked()
{
this->progressBar->show();


// Start the computation.<br /> QFuture&amp;lt;void&amp;gt; future = QtConcurrent::run(&amp;this-&gt;MyObject, &amp;MyClass::LongFunction);<br /> this-&gt;FutureWatcher.setFuture(future);<br />}<br /></code>
// Start the computation.
QFuture<void> future = QtConcurrent::run(&amp;this->MyObject, &amp;MyClass::LongFunction);
this->FutureWatcher.setFuture(future);
}
</code>


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


<code><br />&amp;lt;?xml version=&quot;1.0&amp;quot; encoding=&quot;UTF-8&amp;quot;?&amp;gt;<br />&lt;ui version=&quot;4.0&amp;quot;&gt;<br /> &lt;class&amp;gt;Form&amp;lt;/class&amp;gt;<br /> &lt;widget class=&quot;QWidget&amp;quot; name=&quot;Form&amp;quot;&gt;<br /> &lt;property name=&quot;geometry&amp;quot;&gt;<br /> &lt;rect&amp;gt;<br /> &lt;x&amp;gt;0&amp;lt;/x&amp;gt;<br /> &lt;y&amp;gt;0&amp;lt;/y&amp;gt;<br /> &lt;width&amp;gt;400&amp;lt;/width&amp;gt;<br /> &lt;height&amp;gt;300&amp;lt;/height&amp;gt;<br /> &lt;/rect&amp;gt;<br /> &lt;/property&amp;gt;<br /> &lt;property name=&quot;windowTitle&amp;quot;&gt;<br /> &lt;string&amp;gt;Form&amp;lt;/string&amp;gt;<br /> &lt;/property&amp;gt;<br /> &lt;layout class=&quot;QVBoxLayout&amp;quot; name=&quot;verticalLayout&amp;quot;&gt;<br /> &lt;item&amp;gt;<br /> &lt;widget class=&quot;QPushButton&amp;quot; name=&quot;pushButton&amp;quot;&gt;<br /> &lt;property name=&quot;text&amp;quot;&gt;<br /> &lt;string&amp;gt;PushButton&amp;lt;/string&amp;gt;<br /> &lt;/property&amp;gt;<br /> &lt;/widget&amp;gt;<br /> &lt;/item&amp;gt;<br /> &lt;item&amp;gt;<br /> &lt;widget class=&quot;QLineEdit&amp;quot; name=&quot;lineEdit&amp;quot;/&amp;gt;<br /> &lt;/item&amp;gt;<br /> &lt;item&amp;gt;<br /> &lt;widget class=&quot;QProgressBar&amp;quot; name=&quot;progressBar&amp;quot;&gt;<br /> &lt;property name=&quot;value&amp;quot;&gt;<br /> &lt;number&amp;gt;24&amp;lt;/number&amp;gt;<br /> &lt;/property&amp;gt;<br /> &lt;/widget&amp;gt;<br /> &lt;/item&amp;gt;<br /> &lt;/layout&amp;gt;<br /> &lt;/widget&amp;gt;<br /> &lt;resources/&amp;gt;<br /> &lt;connections/&amp;gt;<br />&lt;/ui&amp;gt;<br /></code>
<code>
<?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>
<item>
<widget class="QLineEdit" name="lineEdit"/>
</item>
<item>
<widget class="QProgressBar" name="progressBar">
<property name="value">
<number>24</number>
</property>
</widget>
</item>
</layout>
</widget>
<resources/>
<connections/>
</ui>
</code>


=== FutureWatcher.cpp ===
=== FutureWatcher.cpp ===


<code>#include &lt;QApplication&amp;gt;<br />#include &lt;QObject&amp;gt;<br />#include &lt;QThread&amp;gt;
<code>#include <QApplication>
#include <QObject>
#include <QThread>


#include &lt;iostream&amp;gt;
#include <iostream>


#include &quot;form.h&amp;quot;
#include "form.h"


int main(int argc, char*argv[])<br />{<br /> QApplication app(argc, argv);
int main(int argc, char*argv[])
{
QApplication app(argc, argv);


Form form;
Form form;
Line 73: Line 143:
form.show();
form.show();


return app.exec&amp;amp;#40;&amp;#41;;<br />}</code>
return app.exec();
}</code>


=== MyClass.h ===
=== MyClass.h ===


<code><br />#ifndef MyClass_H<br />#define MyClass_H
<code>
#ifndef MyClass_H
#define MyClass_H


#include &lt;iostream&amp;gt;
#include <iostream>


class MyClass<br />{<br />public:
class MyClass
{
public:


void LongFunction()<br /> {<br /> for( int count = 0; count &lt; 5; count++ )<br /> {<br /> sleep( 1 );<br /> std::cout &lt;&lt; &quot;Ping long!&quot; &lt;&lt; std::endl;<br /> }<br /> }<br />};
void LongFunction()
{
for( int count = 0; count < 5; count++ )
{
sleep( 1 );
std::cout << "Ping long!" << std::endl;
}
}
};


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


=== CMakeLists.txt ===
=== CMakeLists.txt ===


<code><br />cmake_minimum_required(VERSION 2.6)
<code>
cmake_minimum_required(VERSION 2.6)


PROJECT (FutureWatcher)
PROJECT (FutureWatcher)


FIND_PACKAGE(Qt4 REQUIRED)<br />INCLUDE ($&amp;#123;QT_USE_FILE&amp;#125;)
FIND_PACKAGE(Qt4 REQUIRED)
INCLUDE (${QT_USE_FILE})


QT4_WRAP_CPP(MOCSrcs form.h)<br />QT4_WRAP_UI(UISrcs form.ui)
QT4_WRAP_CPP(MOCSrcs form.h)
QT4_WRAP_UI(UISrcs form.ui)


include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})
include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})


ADD_EXECUTABLE(FutureWatcher FutureWatcher.cpp MyClass.cpp form.cpp ${MOCSrcs} ${UISrcs})<br />TARGET_LINK_LIBRARIES(FutureWatcher ${QT_LIBRARIES})<br /></code>
ADD_EXECUTABLE(FutureWatcher FutureWatcher.cpp MyClass.cpp form.cpp ${MOCSrcs} ${UISrcs})
TARGET_LINK_LIBRARIES(FutureWatcher ${QT_LIBRARIES})
</code>


== QProgressDialog Example ==
== QProgressDialog Example ==
Line 105: Line 194:
=== form.h ===
=== form.h ===


<code><br />#ifndef FORM_H<br />#define FORM_H
<code>
#ifndef FORM_H
#define FORM_H


#include &quot;ui_form.h&amp;quot;
#include "ui_form.h"


#include &lt;QFutureWatcher&amp;gt;
#include <QFutureWatcher>


#include &quot;MyClass.h&amp;quot;
#include "MyClass.h"


class QProgressDialog;
class QProgressDialog;


class Form : public QWidget, private Ui::Form<br />{<br />Q_OBJECT
class Form : public QWidget, private Ui::Form
{
Q_OBJECT


public slots:
public slots:


void slot_finished();<br /> void on_pushButton_clicked();
void slot_finished();
void on_pushButton_clicked();


public:<br /> Form(QWidget '''parent = 0);
public:
<br />private:<br /> QFutureWatcher&amp;lt;void&amp;gt; FutureWatcher;<br /> MyClass MyObject;<br /> QProgressDialog''' ProgressDialog;<br />};
Form(QWidget '''parent = 0);


#endif<br /></code>
private:
QFutureWatcher<void> FutureWatcher;
MyClass MyObject;
QProgressDialog''' ProgressDialog;
};
 
#endif
</code>


=== form.cpp ===
=== form.cpp ===


<code><br />#include &lt;QtGui&amp;gt;<br />#include &lt;QImage&amp;gt;
<code>
#include <QtGui>
#include <QImage>


#include &quot;form.h&amp;quot;
#include "form.h"


#include &lt;iostream&amp;gt;
#include <iostream>


Form::Form(QWidget *parent)<br /> : QWidget(parent)<br />{<br /> setupUi(this);
Form::Form(QWidget *parent)
: QWidget(parent)
{
setupUi(this);


this-&gt;ProgressDialog = new QProgressDialog(this);
this->ProgressDialog = new QProgressDialog(this);


connect(&amp;this-&gt;FutureWatcher, SIGNAL (finished()), this, SLOT (slot_finished()));<br /> connect(&amp;this-&gt;FutureWatcher, SIGNAL (finished()), this-&gt;ProgressDialog , SLOT (cancel()));
connect(&amp;this->FutureWatcher, SIGNAL (finished()), this, SLOT (slot_finished()));
connect(&amp;this->FutureWatcher, SIGNAL (finished()), this->ProgressDialog , SLOT (cancel()));


}
}


void Form::slot_finished()<br />{<br /> std::cout &lt;&lt; &quot;Finshed&amp;quot; &lt;&lt; std::endl;<br />}
void Form::slot_finished()
{
std::cout << "Finshed" << std::endl;
}


void Form::on_pushButton_clicked()<br />{<br /> // Start the computation.<br /> QFuture&amp;lt;void&amp;gt; future = QtConcurrent::run(&amp;this-&gt;MyObject, &amp;MyClass::LongFunction);<br /> this-&gt;FutureWatcher.setFuture(future);
void Form::on_pushButton_clicked()
{
// Start the computation.
QFuture<void> future = QtConcurrent::run(&amp;this->MyObject, &amp;MyClass::LongFunction);
this->FutureWatcher.setFuture(future);


this-&gt;ProgressDialog-&gt;setMinimum(0);<br /> this-&gt;ProgressDialog-&gt;setMaximum(0);<br /> this-&gt;ProgressDialog-&gt;setWindowModality(Qt::WindowModal);<br /> this-&gt;ProgressDialog-&gt;exec&amp;amp;#40;&amp;#41;;
this->ProgressDialog->setMinimum(0);
this->ProgressDialog->setMaximum(0);
this->ProgressDialog->setWindowModality(Qt::WindowModal);
this->ProgressDialog->exec();


}<br /></code>
}
</code>


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


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


MyClass.h<br /><code><br />#ifndef MyClass_H<br />#define MyClass_H
MyClass.h
<code>
#ifndef MyClass_H
#define MyClass_H


#include &lt;iostream&amp;gt;
#include <iostream>


class MyClass<br />{<br />public:
class MyClass
{
public:


void LongFunction()<br /> {<br /> for( int count = 0; count &lt; 5; count++ )<br /> {<br /> sleep( 1 );<br /> std::cout &lt;&lt; &quot;Ping long!&quot; &lt;&lt; std::endl;<br /> }<br /> }<br />};
void LongFunction()
{
for( int count = 0; count < 5; count++ )
{
sleep( 1 );
std::cout << "Ping long!" << std::endl;
}
}
};


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


=== FutureWatcherProgressDialog.cpp ===
=== FutureWatcherProgressDialog.cpp ===


<code>#include &lt;QApplication&amp;gt;<br />#include &lt;QObject&amp;gt;<br />#include &lt;QThread&amp;gt;
<code>#include <QApplication>
#include <QObject>
#include <QThread>


#include &lt;iostream&amp;gt;
#include <iostream>


#include &quot;form.h&amp;quot;
#include "form.h"


int main(int argc, char*argv[])<br />{<br /> QApplication app(argc, argv);
int main(int argc, char*argv[])
{
QApplication app(argc, argv);


Form form;
Form form;
Line 178: Line 343:
form.show();
form.show();


return app.exec&amp;amp;#40;&amp;#41;;
return app.exec();

Revision as of 08:46, 25 February 2015


[toc align_right="yes" depth="3"]

Progress Bar

It is often necessary to display a progress bar while a long operation is happening. The case we are concerned about in this example is when there is no easy way to track the progress of the operation - all that is known is when it is done. There are many ways to do this. You could use a progressBar widget on your widget and run the operation in a different thread (using moveToThread()). This typically requires a special object to be created (a subclass of "QObject":http://developer.qt.nokia.com/doc/qt-4.8/qobject.html that runs the operation and then emits a finished() signal), which can be a pain if you need to do this for many different operations.

However, using "QFutureWatcher":http://developer.qt.nokia.com/doc/qt-4.8/qfuturewatcher.html and "QtConcurrent::run()":http://developer.qt.nokia.com/doc/qt-4.8/qtconcurrentrun.html#run, this is extremely easy. Below we demonstrate how to use this technique with both a QProgressDialog and a QProgressBar.

QProgressBar Example

form.h

#ifndef FORM_H
#define FORM_H

#include "ui_form.h"

#include <QFutureWatcher>

#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:
 QFutureWatcher<void> FutureWatcher;
 MyClass MyObject;
};

#endif

form.cpp

#include <QtGui>
#include <QImage>

#include "form.h"

#include <iostream>

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

this->progressBar->setMinimum(0);
 this->progressBar->setMaximum(0);
 this->progressBar->hide();

connect(&amp;this->FutureWatcher, SIGNAL (finished()), this, SLOT (slot_finished()));

}

void Form::slot_finished()
{
 this->progressBar->hide();
}

void Form::on_pushButton_clicked()
{
 this->progressBar->show();

// Start the computation.
 QFuture<void> future = QtConcurrent::run(&amp;this->MyObject, &amp;MyClass::LongFunction);
 this->FutureWatcher.setFuture(future);
}

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>
 <item>
 <widget class="QLineEdit" name="lineEdit"/>
 </item>
 <item>
 <widget class="QProgressBar" name="progressBar">
 <property name="value">
 <number>24</number>
 </property>
 </widget>
 </item>
 </layout>
 </widget>
 <resources/>
 <connections/>
</ui>

FutureWatcher.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();
}

MyClass.h

#ifndef MyClass_H
#define MyClass_H

#include <iostream>

class MyClass
{
public:

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

#endif

CMakeLists.txt

cmake_minimum_required(VERSION 2.6)

PROJECT (FutureWatcher)

FIND_PACKAGE(Qt4 REQUIRED)
INCLUDE (${QT_USE_FILE})

QT4_WRAP_CPP(MOCSrcs form.h)
QT4_WRAP_UI(UISrcs form.ui)

include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})

ADD_EXECUTABLE(FutureWatcher FutureWatcher.cpp MyClass.cpp form.cpp ${MOCSrcs} ${UISrcs})
TARGET_LINK_LIBRARIES(FutureWatcher ${QT_LIBRARIES})

QProgressDialog Example

form.h

#ifndef FORM_H
#define FORM_H

#include "ui_form.h"

#include <QFutureWatcher>

#include "MyClass.h"

class QProgressDialog;

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

public slots:

void slot_finished();
 void on_pushButton_clicked();

public:
 Form(QWidget '''parent = 0);

private:
 QFutureWatcher<void> FutureWatcher;
 MyClass MyObject;
 QProgressDialog''' ProgressDialog;
};

#endif

form.cpp

#include <QtGui>
#include <QImage>

#include "form.h"

#include <iostream>

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

this->ProgressDialog = new QProgressDialog(this);

connect(&amp;this->FutureWatcher, SIGNAL (finished()), this, SLOT (slot_finished()));
 connect(&amp;this->FutureWatcher, SIGNAL (finished()), this->ProgressDialog , SLOT (cancel()));

}

void Form::slot_finished()
{
 std::cout << "Finshed" << std::endl;
}

void Form::on_pushButton_clicked()
{
 // Start the computation.
 QFuture<void> future = QtConcurrent::run(&amp;this->MyObject, &amp;MyClass::LongFunction);
 this->FutureWatcher.setFuture(future);

this->ProgressDialog->setMinimum(0);
 this->ProgressDialog->setMaximum(0);
 this->ProgressDialog->setWindowModality(Qt::WindowModal);
 this->ProgressDialog->exec();

}

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 MyClass
{
public:

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

#endif

FutureWatcherProgressDialog.cpp

#include <QApplication>

  1. include <QObject>
  2. include <QThread>
  1. include <iostream>
  1. include "form.h"

int main(int argc, char*argv[]) {

QApplication app(argc, argv);

Form form;

form.show();

return app.exec();