Correct way to remove content from layout?

[SPlatten]

I'm using Qt 5.9.2 on Windows 10 with MSVC2015. I have a function:

void MyClass::removeContent(QLayout* pLayout) {
    if ( pLayout == nullptr ) {
        return;
    }
    while( QLayoutItem* pItem = pLayout->takeAt(0) ) {
        if ( QWidget* pWidget = pItem->widget() ) {
            pWidget->deleteLater();
        } else if ( QLayout* pChildLayout = pItem->layout() ) {
            removeContent(pChildLayout);
            pChildLayout->deleteLater();
        }
    }
}

I am seeing:

QFormLayout::takeAt: Invalid index 0

Is there anything I can do to prevent this message from occurring?

I've modified the initial if condition to:

    if ( pLayout == nullptr || pLayout->children().size() == 0  ) {

[Edit], changed again to:

    if ( pLayout == nullptr || pLayout->count() == 0  ) {

Still seeing the same thing.

[J.Hilk]

@SPlatten what about

while(  pLayout->count() ) {
        QLayoutItem* pItem = pLayout->takeAt(0);
        if ( QWidget* pWidget = pItem->widget() ) {
            pWidget->deleteLater();
        } else if ( QLayout* pChildLayout = pItem->layout() ) {
            removeContent(pChildLayout);
            pChildLayout->deleteLater();
        }
    }

[raven-worx]

@SPlatten
pLayout->children().size() should rather be pLayout->count()

[SPlatten]

@raven-worx thank you, just tried that, same result.

[jsulm]

@SPlatten said in Correct way to remove content from layout?:

QFormLayout::takeAt: Invalid index 0

Well, on last iteration you will get this warning as there is nothing to take from the layout anymore. Replace your while() loop with a for().

[J.Hilk]

@SPlatten what about

while(  pLayout->count() ) {
        QLayoutItem* pItem = pLayout->takeAt(0);
        if ( QWidget* pWidget = pItem->widget() ) {
            pWidget->deleteLater();
        } else if ( QLayout* pChildLayout = pItem->layout() ) {
            removeContent(pChildLayout);
            pChildLayout->deleteLater();
        }
    }

[mrjj]

Hi

I was wondering if

while( pLayout->count && QLayoutItem* pItem = pLayout->takeAt(0) )

would do it ?

ps. I like @J-Hilk version better as we don't have to rely on lazy evaluation from the compiler

[SPlatten]

@J-Hilk , perfect, thank you!