QLayout attempting to add qlayout

gully

My hierarchy is the following.
A Dialog contains Vertical Layout
Vertical Layout contains a Tab Widget and a Horizontal Layout
The Horizontal Layout contains a label and a textbox.

My goal is to ensure that right parenting is done to the controls and the layouts so that I donot have to clean-up objects/garbage collect the controls created with

new

The code is of the following
    dialog = new QDialog();
    dialog_vertical_layout = new QVBoxLayout(dialog);
    tabWidget = new QTabWidget(dialog);

    executeMetadataLayout=new QHBoxLayout(dialog);
    execute_button=new QPushButton(dialog);
    execute_button->setText(QString("Execute"));

    dialog_vertical_layout->addWidget(tabWidget);
    dialog_vertical_layout->addLayout(executeMetadataLayout);

    dialog->setAttribute(Qt::WA_DeleteOnClose);
    dialog->show();

I am getting warnings with QLayout attempting to add qlayout what is going wrong?
Also to achieve my goals am I in the right direction?

Christian Ehrlicher

@gully said in QLayout attempting to add qlayout:

executeMetadataLayout=new QHBoxLayout(dialog);

You're creating a second layout with dialog as parent. Since this ctor automatically adds the layout to the widget you'll get an error because there is already a layout set.
I don't see a reason for the second layout since you've only two widgets which perfectly fit into the first QVBoxLayout.
Also I would use Qt designer instead creating the ui elements by hand.

gully

@Christian-Ehrlicher I am setting the parent so that I donot have to do garbage collection separately. The parent child relationship ensures that the child objects (created with new especially) are deleted once the parent is destroyed.

How can I in this case maintain automatic garbage collection and set the layouts at the same time?

Christian Ehrlicher

You can only set one layout to one widget at the same time (therefore the warning). As I said - I don't see what's the second layout is for in your example. Simply use the Qt designer for such stuff and you're fine.

gully

@Christian-Ehrlicher using QT designer is just going to help me run away from this problem rather than solving it. I have my reasons not to use QT Designer.

I understand where I am going wrong. I know how to solve it as well. What I donot understand is how can I create layout as well as maintain the parent-child relationship so that automatic garbage collection is ensured

Christian Ehrlicher

Since a widget can't have two layouts I don't see a reason why you need a second layout with this widget as parent. Just use the widget where the layout is used for (which is done implicit in the ctor or with widget->setLayout())

gully

@Christian-Ehrlicher just looking for your confirmation/rejection here , if I do setWidget() or setLayout does these function automatically set parent child relationship- so that the objects created on heap are not required to be garbage collection manually/writing code for it ?

aha_1980

@gully just use the help: http://doc.qt.io/qt-5/qlayout.html#addItem which is called from addWidget, takes ownership of the added widget. Thats what you want.