QPushButton will not update/repaint after button press

jaramos2409

alt text

I have three stacks represented as QPushButtons. What I want to do is, when you click on the second pole, the first pole loses it's top disk, and that disk is stacked onto the empty second pole.

The problem I am having is that, after I click on the second pole, the first pole repaints and loses it's top disk, but the second pole does not gain the lost disk. I have tried forcing it to do so with repaint(), but I have had no luck.

Each pole is represented in an inherited QWidget class. Each pole contains a stack of disks (which themselves are represented as an inherited QWidget class). I initialize the poles like so at the programs launch:

    poles[0] = new pole(0, ui->spinBox->value(), ui->stack_one);
    poles[1] = new pole(1, 0, ui->stack_two);
    poles[2] = new pole(2, 0, ui->stack_three);

...
//pole constructor
    this->resize(parent->geometry().width(), parent->geometry().height());
    n = num;
    numDisks = count;

    int j = numDisks;
    for (int i = 0; i < numDisks; i++)
    {
        stack.push_back(new disk(j, i, this, parent));
        j--;
    }

When the second pole is clicked, it triggers it's slot function and proceeds to call function after function to move the disk.

void TowerOfHanoi::on_stack_two_clicked()
{
    move.moveToStack(poles[1]);
}
...
void moveHandler::moveToStack(pole* toStack)
{
    toStack->put(activePole->take());
}
...
disk* pole::take()
{
    disk* topDisk = NULL;

    if (!stack.empty())
    {
        topDisk = stack.back();
        stack.pop_back();
    }

    return topDisk;
}
...
bool pole::put(disk* d)
{
    bool success = false;

    if (stack.empty() || stack.back()->Size() > d->Size())
    {
        d->setPolePos(this, stack.capacity());
        d->setParent(this->parentWidget());
        stack.push_back(d);
        d->repaint();
        d->parentWidget()->repaint();
        d->parentWidget()->parentWidget()->repaint();
        success = true;
    }


    return success;
}

After debugging thoroughly, I'm confident the taken disk is put into the second pole's stack of disks. What I find weird is that, using QDebug, I found that only the paintEvent()'s of the disks on top of the first pole are triggered automatically after

  d->setParent(this->parentWidget());

but not the disk on the second pole.

Could someone help me figure out why or how to repaint the other pole's? I'm new to Qt so I apologize if the answer if obvious.

mrjj

hi and welcome
The code looks fine and well structured so I assume the stack part is working as intended. Nothing obvious :)

If you from start give pole 2 some disks, they are painted as expected?

To test if its a repaint issue, try cover the app with another window and
remove it again. that should trigger some updates.

jaramos2409

@mrjj

If I add disks from the beginning, they do paint:

    poles[0] = new pole(0, ui->spinBox->value(), ui->stack_one);
    poles[1] = new pole(1, 4, ui->stack_two);
    poles[2] = new pole(2, 6, ui->stack_three);

alt text

Covering up the window with other windows does not seem to paint the disks on the pole.

Edit: I think it's worth mentioning that I have the following piece of code in disk's overriden paintEvent:

qDebug() << "Disk paintEvent triggered " << on->parentWidget()->accessibleName() << size;

and the output I get for the default launch is :

Disk paintEvent triggered  "s1" 8
...
Disk paintEvent triggered  "s1" 1

and when I fill up the other two poles at startup:

Disk paintEvent triggered  "s2" 4
...
Disk paintEvent triggered  "s2" 1
Disk paintEvent triggered  "s3" 6
...
Disk paintEvent triggered  "s3" 1
...
Disk paintEvent triggered  "s1" 1

so the paintEvents are being triggered for disks on on other pole's at startup.

jaramos2409

Ah I managed to fix it!

The problem was that, after setting a new parent for the disk, it turns the Widget invisible and all I had to do was use show() to make it reappear again. I have to be more attentive with the documentation next time.

Thanks for trying to help me!

mrjj

@jaramos2409
hehe good found
I was about to ask about show as normally
widget->update()/repaint() is enough for it to redraw