QTimer class and timeout() signal and slot not connecting

[di_zou]

I have a widget:

//foo.h
#include <QTimer>
...
 
class foo : public QWidget
{
...
private slots:
     void on_timer_timeout();
...
private:
     QTimer *timer;
...
}

//foo.h
#include <QTimer>
...

class foo : public QWidget
{
...
private slots:
     void on_timer_timeout();
...
private:
     QTimer *timer;
...
}

To copy to clipboard, switch view to plain text mode 

and

//foo.cpp
#include "foo.h"
foo::foo(QWidget *parent)
	: QWidget(parent)
{
     ...
     timer = new QTimer(this);
     timer->start(5);
     ...
}
 
void foo::on_timer_timeout()
{
     //do stuff
}

//foo.cpp
#include "foo.h"
foo::foo(QWidget *parent)
	: QWidget(parent)
{
     ...
     timer = new QTimer(this);
     timer->start(5);
     ...
}

void foo::on_timer_timeout()
{
     //do stuff
}

To copy to clipboard, switch view to plain text mode 

When I run the program that creates the widget foo, I get the error:
QMetaObject::connectSlotsByName: No matching signal for on_timer_timeout().

What is the problem?

[Boron]

Don't you miss a line like this?

connect( timer, SIGNAL(timeout()), SLOT(on_timer_timeout()) );

connect( timer, SIGNAL(timeout()), SLOT(on_timer_timeout()) );

To copy to clipboard, switch view to plain text mode 

How shall the program know what to call when the signal timeout() is emitted?
And I have no idea what to do with you error message.

[faldzip]

the:

void on_xxx_yyy();

void on_xxx_yyy();

To copy to clipboard, switch view to plain text mode 

slots works fine but the xxx is not a C++ variable name but the object name (QObject::objectName(), QObject::setObjectName()), and didn't set any object name to your timer. So better do it in standard way, it means connect slot with signal manualy:

private slots:
    void myTimeoutSlot();
private:
    QTimer *timer;

private slots:
    void myTimeoutSlot();
private:
    QTimer *timer;

To copy to clipboard, switch view to plain text mode 

. . .
connect(timer, SIGNAL(timeout()), this, SLOT(myTimeoutSlot()));
. . .

. . .
connect(timer, SIGNAL(timeout()), this, SLOT(myTimeoutSlot()));
. . .

To copy to clipboard, switch view to plain text mode