[Qt-interest] Passing a variable back from a form

[Scott Aron Bloom]

Don't over think this one :)

I would use a QSignalMapper

It allows you map the clicked of multiple QPushButtons to a signal with
a value.. Very straight forward...

Have a slot inside the dialog that gets the number from the signal
stores it in the dialog, and calls accept() on the dialog..

Then query the dialog for the value clicked....

Scott


-----Original Message-----
From: qt-interest-bounces+scott.bloom=onshorecs.com at qt.nokia.com
[mailto:qt-interest-bounces+scott.bloom=onshorecs.com at qt.nokia.com] On
Behalf Of Robert Wood
Sent: Tuesday, March 22, 2011 4:33 PM
To: qt-interest at qt.nokia.com
Subject: Re: [Qt-interest] Passing a variable back from a form

Hi and thanks for the reply. I don't understand how this would work. If
I connect the clicked signal to closed slot in the Signals/Slot editor,
it does close the dialogue down. What I am not clear is where the emit
would be put and also I don't follow how the calling form would receive
the value.

I have had a look at this:

http://doc.qt.nokia.com/latest/signalsandslots.html

After searching Google for Qt emit.

Also looked at various other pages that reference emit, but I can't
follow them and they seem different to my situation.

I need each button to return a different and unique value to the calling
form which the calling form will then use.

I probably have a blindness to this after spending several hours on it
so am maybe missing something obvious.

I've done this several times before with just one button closing the
form and sending a value back, but it's this whole thing of multiple
buttons closing the form and sending different values back that is
stumping me.

The pointer thing would work if I could make the passed pointer global
within the called dialogue or if I knew how to make that pointer
accessible to each of the buttons' slots.

Thanks again for your help. :~)

On 22/03/11 22:27, NoRulez wrote:
> Hi,
>
> you could connect the buttons to the dialogs close() slot and emit a 
> signal with your value (e.g. emit buttonValue(42); )
>
> Best Regards
>
> Am 22.03.2011 um 23:12 schrieb Robert
Wood<robert.wood at apostrophe.co.uk>:
>
>> I am trying to create a pop-up window that has a load of JPEGs on it.
>> When one of the JPEGs (which is put on a push button) is clicked, I 
>> want the form to close and a value dependent on which button is 
>> pressed passed back to the calling form.
>>
>> I have tried a few things such as making it a dialogue box, but this 
>> doesn't work as you seem to need to press the OK button. I tried this

>> (using a naughty global variable!):
>>
>>
>> // This routine does return the value and close the form
>> quint16 config_dialogue::returnConfig(void)
>> {
>>
>>      return RetVal;
>>
>> }
>>
>> // This is one of the JPEG buttons; it does set the RetVal to 42 // 
>> but it does not shut the form down and pass the value back
>> quint16 config_dialogue::nineGroups(void) {
>>
>>      RetVal = 42;
>>      returnConfig();
>>
>> }
>>
>> Then used this from the calling from:
>>
>>     config_dialogue dialogue(this);
>>
>>     if (dialogue.exec() == QDialog::Accepted)
>>         {
>>         ConfigNumber = dialogue.returnConfig();
>>         ui->label->setText("Number returned" +
QString::number(ConfigNumber));
>>         }
>>
>> And although I do get 42 back. I still have to press the OK button.
>>
>> So, is there a way to have a load of buttons on a form and whichever 
>> button you press it passes a unique number back to the calling form 
>> please? It doesn't have to be a dialogue, just a normal form will be
fine.
>>
>> I did try passing a pointer to a variable to the dialogue/form and 
>> making the dialogue modal, but the scope of it is only within the  
>> class constructor. I guess there might be a way of having this 
>> pointer accessible within the rest of the class, but this would be a 
>> weakness in my C++ knowledge. (Yes I know this isn't a C++ tutorial 
>> forum, so if this question offends please just ignore me!).
>>
>> Thanks!
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