[Qt-interest] problem with signal/slot

[Andre Somers]

Op Di, 21 december, 2010 1:47 pm, schreef prashant bhutani:

>> > this is my code :
>> >
>> > class CustomScene : public QGraphicsScene
>> > {
>> >
>> >     Q_OBJECT
>> >     public:
>> >         CustomScene()
>> >         {
>> >               alphaSlider = new QSlider(Qt::Horizontal);
>> >             alphaSlider->setTickInterval(1);
>> >             alphaSlider->setRange(0,255);
>> >             alphaSlider->setMinimumSize(105,20);
>> >             alphaSlider->move(6,222);
>> >             alphaSlider->setToolTip("Opacity");
>> >             connect( alphaSlider, SIGNAL(valueChanged(int)),
>> > SLOT(updateAlphaValue()) );
>>
> Sorry but shouldn't this connect method refer to second object?
> like connect(&obj1, signal, &obj2, slot)

No, that is not really needed. There are overloaded versions of connect.
If you ommit the second object reference, it will refer to this.
These two statements are equivalent:
connect(obj1Ptr, SIGNAL(theSignal()), this, SLOT(theSlot()));
connect(obj1Ptr, SIGNAL(theSignal()), SLOT(theSlot()));

André