Create Qt layout with fixed height

问题:

I want to create a Qt window that contains two layouts, one fixed height that contains a list of buttons at the top and one that fills the remaning space with a layout that centers a widget vertically and horizontally as per the image below.

How should i be laying out my layouts/widgets. Ive tried a few options with nested horizontal and vertical layouts to no avail

回答1:

Try making the pink box a QWidget with a QHBoxLayout (rather than just making it a layout). The reason is that QLayouts don't provide functionality to make fixed sizes, but QWidgets do.

// first create the four widgets at the top left,
// and use QWidget::setFixedWidth() on each of them.

// then set up the top widget (composed of the four smaller widgets):
QWidget *topWidget = new QWidget;
QHBoxLayout *topWidgetLayout = new QHBoxLayout(topWidget);
topWidgetLayout->addWidget(widget1);
topWidgetLayout->addWidget(widget2);
topWidgetLayout->addWidget(widget3);
topWidgetLayout->addWidget(widget4);
topWidgetLayout->addStretch(1); // add the stretch
topWidget->setFixedHeight(50);

// now put the bottom (centered) widget into its own QHBoxLayout
QHBoxLayout *hLayout = new QHBoxLayout;
hLayout->addStretch(1);
hLayout->addWidget(bottomWidget);
hLayout->addStretch(1);
bottomWidget->setFixedSize(QSize(50, 50));

// now use a QVBoxLayout to lay everything out
QVBoxLayout *mainLayout = new QVBoxLayout;
mainLayout->addWidget(topWidget);
mainLayout->addStretch(1);
mainLayout->addLayout(hLayout);
mainLayout->addStretch(1);

If you really want to have two separate layouts--one for the pink box and one for the blue box--the idea is basically the same except you'd make the blue box into its own QVBoxLayout, and then use:

mainLayout->addWidget(topWidget);
mainLayout->addLayout(bottomLayout);