layout set and widget as parent...

[1XU7]

Hello!

is this....

QWidget* wdg = new QWidget(this);
QHBoxLayout* lay = new QHBoxLayout(wdg); //does internally applies layout to wdg parent?
QPushButton* pbt = new QPushButton(wdg); //does internally layout applied to wdg add the button?

the same to this?

QWidget* wdg = new QWidget(this);
QHBoxLayout* lay = new QHBoxLayout;
wdg->setLayout(lay);
QPushButton* pbt = new QPushButton;
lay->addWidget(pbt);

[Christian Ehrlicher]

@1XU7 said in layout set and widget as parent...:

i tought by setting wdg as parent to button, and wdg has lay as layout, the layout would add button automatically...

No and I don't see any evidence that a QObject-based parent-child relationship should have something to do with a layout.
The other way round is correct - when you add a widget to another widgets layout then the other widget is becoming the parent of the child because otherwise parent-child stuff like e.g. event propagation would not work. So no, no need to set a parent in your code but it will also not hurt and makes it more obvious what you're trying to do.

[Christian Ehrlicher]

According to the documentation, yes - at least for the Q

I misread your post - since you don't add pbt to a layout it will look different. Layouts and parent are two different concepts.

[1XU7]

@Christian-Ehrlicher

i tought by setting wdg as parent to button, and wdg has lay as layout, the layout would add button automatically... but you mean that is not made.. i need to manually add button to layout:

QWidget* wdg = new QWidget(this);
QHBoxLayout* lay = new QHBoxLayout(wdg);
QPushButton* pbt = new QPushButton(wdg);  //it is necesary to set wdg as parent here?
lay->addWidget(pbt);

[Christian Ehrlicher]

@1XU7 said in layout set and widget as parent...:

i tought by setting wdg as parent to button, and wdg has lay as layout, the layout would add button automatically...

No and I don't see any evidence that a QObject-based parent-child relationship should have something to do with a layout.
The other way round is correct - when you add a widget to another widgets layout then the other widget is becoming the parent of the child because otherwise parent-child stuff like e.g. event propagation would not work. So no, no need to set a parent in your code but it will also not hurt and makes it more obvious what you're trying to do.