QGroupBox does not fit into layouts

[pauledd]

Hi
I have a QDialog in which is a QTabWidget. In this widget should be some groups. One group is "Settings" that consists of a qlabel and a qlineedit per row. I will add more pairs later. I want to have a border arround this group so I thought qgroupbox might be proper. I simply dont get behind the qgroupbox magic... I dont know how to shrink the Settings-qgroupbox to the size of the label and the lineedit. I managed to shrink it vertically but it does not horizontally.
Here is an image how it looks current.
https://pauledd.files.wordpress.com/2016/08/pat.png

GeneralTab::GeneralTab(QWidget *parent)
	:QWidget(parent)
{	
	QLabel *videoDeviceLabel = new QLabel("Video Device:");
	QLineEdit *videoDeviceValueLabel = new QLineEdit("/dev/video0");
	QHBoxLayout *horizontalLayout = new QHBoxLayout;
	horizontalLayout->addWidget(videoDeviceLabel);
	horizontalLayout->addWidget(videoDeviceValueLabel);
	horizontalLayout->addStretch(1);
	QGroupBox *box = new QGroupBox("Settings");
	QVBoxLayout *mainLayout = new QVBoxLayout;
	mainLayout->addWidget(box);
	mainLayout->addStretch(1);
	box->setLayout(horizontalLayout);
	setLayout(mainLayout);
}

any ideas?

[VRonin]

it's not a problem of the groupbox but of the layout you put it in

change

    QVBoxLayout *mainLayout = new QVBoxLayout;
    mainLayout->addWidget(box);
    mainLayout->addStretch(1);

into

    QGridLayout *mainLayout = new QGridLayout ;
    mainLayout->addWidget(box,0,0);
    mainLayout->additem(new QSpacerItem(10,10,QSizePolicy::Expanding,QSizePolicy::Preferred),0,1);
mainLayout->additem(new QSpacerItem(10,10,QSizePolicy::Preferred,QSizePolicy::Expanding),1,0);

[pauledd]

Ok, now I get this:
https://pauledd.files.wordpress.com/2016/08/pat2.png
The GroupBox seems to horizontally take half of the dialog but does not shrink to the end
of the qlineedit.

[pauledd]

I just tried a new project and just by using the form editor and that was so easy:
https://pauledd.files.wordpress.com/2016/08/pat3.png

Its just a button and a lineedit in a horizontal layout in a group box. Why cant I do this programmatically?

[SGaist]

Hi,

Since you want a QLabel + QLineEdit, why not use QFromLayout ?

That should also simplify size handling.

Hope it helps

[VRonin]

remove horizontalLayout->addStretch(1); that is what is taking space after the line edit

[pauledd]

@SGaist thank you, I took QFormLayout into account.
@VRonin also thank you!
I can not believe that it would take so much code to get this done...
After starting over and over again I came up with this:

GeneralTab::GeneralTab(QWidget *parent)
	:QWidget(parent)
{	
			QLineEdit *lineEdit = new QLineEdit("/dev/video0");
			QGroupBox *groupBox = new QGroupBox("Settings",this);
			groupBox->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
			QFormLayout *formLayout = new QFormLayout(groupBox);
			formLayout->addRow("Video Device: ",lineEdit);
}

and this looks exactly what I wanted, two widgets with a nice group box border sized to minimal space usage:
https://pauledd.files.wordpress.com/2016/08/pat4.png
I dont really know If this code is correct or might produce trouble but at least I dont find any errors at the moment.