Read access violation

ikuris

Hello,

I have a list of checkbox ,

QCheckBox* cblist[6];

I am initializing that list in consturctor after setUI method

    ui->setupUi(this);
    cblist[0] = ui->checkBox;
    cblist[1] = ui->checkBox_2;
    cblist[2] = ui->checkBox_3;
    cblist[3] = ui->checkBox_4;
    cblist[4] = ui->checkBox_5;
    cblist[5] = ui->checkBox_6;

I am changing their check state and color style in another slot function

    ui->checkBox->setChecked(true);
    ui->checkBox_2->setChecked(false);
    ui->checkBox_3->setChecked(true);
    ui->checkBox_4->setChecked(false);
    ui->checkBox_5->setChecked(true);
    ui->checkBox_6->setChecked(false);

    for(auto cbIndex = 0; cbIndex < 6; ++cbIndex)
    {
        if(cblist[cbIndex]->isChecked())
        {
            cblist[cbIndex]->setStyleSheet("QCheckBox { color : #55FF77; }");
        }
        else
        {
            cblist[cbIndex]->setStyleSheet("QCheckBox { color : #FF2222; }");
        }
    }

The strange thing is when I am adding another widget from creator it does give me a error (0xC0000005: Access violation reading location). I am certain that I am not deleting or modifying that cblist array and I dont have a logical example or explanation, but I couldnt find anything and it does keep going like that.

Thank you for your time and help.

Christian Ehrlicher

@ikuris said in Read access violation:

I am certain that I am not deleting or modifying that cblist array

Don't be certain - check it by yourself by e.g. printing out the pointer values.

Kent-Dorfman

@ikuris said in Read access violation:

I am changing their check state and color style in another slot function

It looks ok but the thing that I'd suspect is that you are calling your slot function BEFORE the constructor is executed.

Something else to think about: modern c++ standards.

the more modern paradigm for handling arrays like you are creating is something like:

std::vector<QCheckBox*> clist; // in class definition

clist = { ui->cb1, ui->cb2, ui->cb3, ui-cb4 }; // in constructor

and then your loops are controlled by clist.size();

In this way you've removed the need for a MAX_INDEX value of checkboxes: a potential source of error.

Here's another shortcut

setStyleSheet(isChecked ? "true style" : "false style");

Gerhard

@ikuris said in Read access violation:

for(auto cbIndex = 0; cbIndex < 6; cbIndex++)

Kent-Dorfman

@Gerhard

pre or post increment makes no difference because the incrementing of loop variant is done at the bottom of the loop, not the top.