SLOT not being called

[steg90]

Hi,

I have the following code :

m_pSliderMapper->setMapping( m_pSlider[0], 0 );
	connect( m_pSlider[0], SIGNAL(valueChanged(int)),m_pSliderMapper,SLOT(map()));
	connect( m_pSliderMapper, SIGNAL(mapped(int)),this,SLOT(ChangeTheTimer(int,int)) );

m_pSliderMapper->setMapping( m_pSlider[0], 0 );
	connect( m_pSlider[0], SIGNAL(valueChanged(int)),m_pSliderMapper,SLOT(map()));
	connect( m_pSliderMapper, SIGNAL(mapped(int)),this,SLOT(ChangeTheTimer(int,int)) );

To copy to clipboard, switch view to plain text mode 

Where m_pSliderMapper is QSignalMapper and m_pSlider is QSlider. Can anyone see a reason why the ChangeTheTimer slot is not being called when I move the slider?

Regards,
Steve

[jpn]

This is an incorrect signal slot connection

connect( m_pSliderMapper, SIGNAL(mapped(int)),this,SLOT(ChangeTheTimer(int,int)) );

connect( m_pSliderMapper, SIGNAL(mapped(int)),this,SLOT(ChangeTheTimer(int,int)) );

To copy to clipboard, switch view to plain text mode 

You can't connect a signal with one parameter to a slot with two parameters.

With given information I can't be sure if this fits your problem, but perhaps you could work it around by giving the second parameter a default value:

void ChangeTheTimer(int foo, int bar = 1234);

void ChangeTheTimer(int foo, int bar = 1234);

To copy to clipboard, switch view to plain text mode 

Then, drop the additional parameter from the connect-statement:

connect( m_pSliderMapper, SIGNAL(mapped(int)),this,SLOT(ChangeTheTimer(int)) );

connect( m_pSliderMapper, SIGNAL(mapped(int)),this,SLOT(ChangeTheTimer(int)) );

To copy to clipboard, switch view to plain text mode 

[steg90]

Thanks as always JPN.

I just use one parameter and get around it in the SLOT.

m_pSliderMapper->setMapping( m_pSlider[0], 0 );
	connect( m_pSlider[0], SIGNAL(valueChanged(int)),m_pSliderMapper,SLOT(map()));
	connect( m_pSliderMapper, SIGNAL(mapped(int)),this,SLOT(ChangeTheTimer(int)) );

m_pSliderMapper->setMapping( m_pSlider[0], 0 );
	connect( m_pSlider[0], SIGNAL(valueChanged(int)),m_pSliderMapper,SLOT(map()));
	connect( m_pSliderMapper, SIGNAL(mapped(int)),this,SLOT(ChangeTheTimer(int)) );

To copy to clipboard, switch view to plain text mode 

void CSendMessage::ChangeTheTimer( int val)
{
	if( m_pSlider[val] )
	{
		int value = m_pSlider[val]->value();
		if( m_pThread[val] )
		{
			m_pThread[val]->m_nTimer = value * 10;
		}
	}
}

void CSendMessage::ChangeTheTimer( int val)
{
	if( m_pSlider[val] )
	{
		int value = m_pSlider[val]->value();
		if( m_pThread[val] )
		{
			m_pThread[val]->m_nTimer = value * 10;
		}
	}
}

To copy to clipboard, switch view to plain text mode 

Regards,
Steve

[ChristianEhrlicher]

How should this work:

connect( m_pSlider[0], SIGNAL(valueChanged(int)),m_pSliderMapper,SLOT(map ()));

?

[jogeshwarakundi]

Actually, if the slot has lesser number of parameters than the signal, Qt just ignores the remaining parameters. It is a perfectly valid scenario right? you are interested only in the event, but not values. but an invocation of a slot with more parameters than the signal would mean that the slot has to be invoked with invalid parameters (in theory) so Qt doesn't accept that. I guess it should have shown some printf about the 2nd conn being wrong at runtime!!!