When are widgets deleted in Qt (QVBoxLayout class)? - c++

Question

I have some simple code to create a new widget using Qt:
Dock::Dock() : QDockWidget() {
label = new QLabel(QLatin1String("TEST"));
QVBoxLayout* layout = new QVBoxLayout();
layout->addWidget(label, 0, Qt::AlignTop);
layout->addStretch(-1);
QWidget* multiWidget = new QWidget();
multiWidget->setLayout(layout);
setWidget(multiWidget);
}
Where label is a private member QLabel* label. My question is: am I responsible for deleting label in Dock's destructor?
I tried changing the code so that label is a std::shared_ptr<QLabel>:
Dock::Dock() : QDockWidget() {
label = std::make_shared<QLabel>(QLatin1String("TEST"));
QVBoxLayout* layout = new QVBoxLayout();
layout->addWidget(label.get(), 0, Qt::AlignTop);
layout->addStretch(-1);
QWidget* multiWidget = new QWidget();
multiWidget->setLayout(layout);
setWidget(multiWidget);
}
So that it is deleted automatically when `Dock' is destroyed but I get an error when I close the program.

Answer 1

In order to properly set up the objects tree you need to do the following:
Create the container widget first,
Create child widget and set it's parent,
Create layout of the container widget,
Add widget to the layout.
Here is the code that demonstrates the mentioned approach:
Dock::Dock()
:
QDockWidget()
{
QWidget* multiWidget = new QWidget;
label = new QLabel(QLatin1String("TEST"), multiWidget); // Set parent
QVBoxLayout* layout = new QVBoxLayout(multiWidget); // Sets layout
layout->addWidget(label, 0, Qt::AlignTop);
layout->addStretch(-1);
setWidget(multiWidget);
}