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Qt: QList QButtonGroup

Hey! I am trying to do the following

    QList<QButtonGroup*> groups;
    for (int i=0; i<nGroup; i++)
    {
        QButtonGroup *objects = new QButtonGroup(this);
        objects->setExclusive(false);
        for (int j=0; j<nObject; j++)
        {
            Led *tempLed = new Led();
            tempLed->setAutoExclusive(false);
            layout->addWidget(tempLed,j,i,Qt::AlignLeft);
            objects->addButton(tempLed);
        }
        groups.append(objects);
    }

And then try doing something like this:

groups.at(1)->button(2)->setChecked(true);

Compiles your code, but throws an unhandled exception at runtime. What am I doing wrong? Any better way to create a QButtonGroup?

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3 answers


The QButtonGroup :: button function returns the button for a specific ID, but you didn't use the ID when you added the button to the buttongroup. QButtonGroup :: button returns 0 in your example, which results in a null pointer access exception.

...
objects->addButton(tempLed);
...

If you change your code to



...
objects->addButton(tempLed, j );
...

your original code will work.

I prefer QList :: at over QList :: operator [] because you don't want to change the value (== pointer) in the list.

+3


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I think the problem is with the at function . It returns a const element and you call a non-const function on it.



Use operator [] instead .

+1


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OK, I solved it this way:

QButtonGroup *bG;
bG = groups[gr];
QAbstractButton *aB = bG->buttons()[obj];
aB->setChecked(command);

Didn't understand what the problem is.

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