[SOLVED] Calling Slots with value/parameter?

MrNoway

so hi again,

I need to call a SLOT with a parameter/value.
how to do this, if i set up like this, the slot is not called

@for (int i=0; i< value_x; i++){

   connect (push_button_here[i], SIGNAL(clicked()), this, SLOT(do_this(i)));

} @

how can this be fixed?
just tried solving this like forever.

thank you already

Jake007

Hi!

"QSignalMapper":http://doc.qt.digia.com/qt/qsignalmapper.html should do the trick.

Regards,
Jake

MrNoway

thanks but you could provide little bit of code,

i dont really understand how to get this run

where should i write my own "do_this(i)" function?

that example doesnt really help me

mlong

Something like this should work, assuming you have a slot do_this(int) in your code.

@
QSignalMapper *signalMapper = new QSignalMapper(this);

for (int i = 0; i < value_x; ++i) {
connect(push_button_here[i], SIGNAL(clicked()), signalMapper, SLOT(map()));
signalMapper->setMapping(push_button_here[i], i);
}

connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(do_this(int)));
@
Brain to keyboard, YMMV

Jake007

I can't find a project in which I played with QSignalMapper, but based on docs, it should be something like this:

@
QSignalMapper *mapper = new QSignalMapper(this);

for(int i=0; i<0; i<value_x; i++)
{
connect(push_button_here[i], SIGNAL(clicked()), mapper, SLOT(map()));
mapper->setMapping(push_button_here[i], i);
}

connect(mapper, SIGNAL(mapped(int)), this, SLOT(do_this(int)));@

Note: Not tested!

MrNoway

[quote author="mlong" date="1354648588"]Something like this should work, assuming you have a slot do_this(int) in your code.

@
QSignalMapper *signalMapper = new QSignalMapper(this);

for (int i = 0; i < value_x; ++i) {
connect(push_button_here[i], SIGNAL(clicked()), signalMapper, SLOT(map()));
signalMapper->setMapping(push_button_here[i], i);
}

connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(do_this(int)));
@
Brain to keyboard, YMMV[/quote]

WOW Thats amazing!

great working!

thanks a lot

Jake007

Don't forget to mark as solved.

And mlong, you were faster :) . I had to read all the docs first.

Regards,
Jake

mlong

Glad it's working :)

And Jake007, I like how our code is very much the same, though. Almost as if we both were modifying the example code.

Jake007

Well... I did modify the example code :) .

Oh and one more solution I forgot to mention.

You could use sender() method ( in do_this(), without parameters), which returns QObject *. You can then cast it to QPushButton * or whatever widget you have. But I wouldn't recommend using it, as there might be problems if you call method directly or is accidentally called with signal from object with different type.
But might come in handy in a few lazy cases ;) .